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linux/fs/io-wq.c

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io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
// SPDX-License-Identifier: GPL-2.0
/*
* Basic worker thread pool for io_uring
*
* Copyright (C) 2019 Jens Axboe
*
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/sched/signal.h>
#include <linux/mm.h>
#include <linux/mmu_context.h>
#include <linux/sched/mm.h>
#include <linux/percpu.h>
#include <linux/slab.h>
#include <linux/kthread.h>
#include <linux/rculist_nulls.h>
#include "io-wq.h"
#define WORKER_IDLE_TIMEOUT (5 * HZ)
enum {
IO_WORKER_F_UP = 1, /* up and active */
IO_WORKER_F_RUNNING = 2, /* account as running */
IO_WORKER_F_FREE = 4, /* worker on free list */
IO_WORKER_F_EXITING = 8, /* worker exiting */
IO_WORKER_F_FIXED = 16, /* static idle worker */
io-wq: add support for bounded vs unbunded work io_uring supports request types that basically have two different lifetimes: 1) Bounded completion time. These are requests like disk reads or writes, which we know will finish in a finite amount of time. 2) Unbounded completion time. These are generally networked IO, where we have no idea how long they will take to complete. Another example is POLL commands. This patch provides support for io-wq to handle these differently, so we don't starve bounded requests by tying up workers for too long. By default all work is bounded, unless otherwise specified in the work item. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08 02:41:16 +08:00
IO_WORKER_F_BOUND = 32, /* is doing bounded work */
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
};
enum {
IO_WQ_BIT_EXIT = 0, /* wq exiting */
IO_WQ_BIT_CANCEL = 1, /* cancel work on list */
io-wq: wait for io_wq_create() to setup necessary workers We currently have a race where if setup is really slow, we can be calling io_wq_destroy() before we're done setting up. This will cause the caller to get stuck waiting for the manager to set things up, but the manager already exited. Fix this by doing a sync setup of the manager. This also fixes the case where if we failed creating workers, we'd also get stuck. In practice this race window was really small, as we already wait for the manager to start. Hence someone would have to call io_wq_destroy() after the task has started, but before it started the first loop. The reported test case forked tons of these, which is why it became an issue. Reported-by: syzbot+0f1cc17f85154f400465@syzkaller.appspotmail.com Fixes: 771b53d033e8 ("io-wq: small threadpool implementation for io_uring") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-19 23:37:07 +08:00
IO_WQ_BIT_ERROR = 2, /* error on setup */
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
};
enum {
IO_WQE_FLAG_STALLED = 1, /* stalled on hash */
};
/*
* One for each thread in a wqe pool
*/
struct io_worker {
refcount_t ref;
unsigned flags;
struct hlist_nulls_node nulls_node;
io-wq: ensure free/busy list browsing see all items We have two lists for workers in io-wq, a busy and a free list. For certain operations we want to browse all workers, and we currently do that by browsing the two separate lists. But since these lists are RCU protected, we can potentially miss workers if they move between the two lists while we're browsing them. Add a third list, all_list, that simply holds all workers. A worker is added to that list when it starts, and removed when it exits. This makes the worker iteration cleaner, too. Reported-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-14 04:54:49 +08:00
struct list_head all_list;
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
struct task_struct *task;
wait_queue_head_t wait;
struct io_wqe *wqe;
io-wq: ensure we have a stable view of ->cur_work for cancellations worker->cur_work is currently protected by the lock of the wqe that the worker belongs to. When we send a signal to a worker, we need a stable view of ->cur_work, so we need to hold that lock. But this doesn't work so well, since we have the opposite order potentially on queueing work. If POLL_ADD is used with a signalfd, then io_poll_wake() is called with the signal lock, and that sometimes needs to insert work items. Add a specific worker lock that protects the current work item. Then we can guarantee that the task we're sending a signal is currently processing the exact work we think it is. Reported-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-14 00:43:34 +08:00
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
struct io_wq_work *cur_work;
io-wq: ensure we have a stable view of ->cur_work for cancellations worker->cur_work is currently protected by the lock of the wqe that the worker belongs to. When we send a signal to a worker, we need a stable view of ->cur_work, so we need to hold that lock. But this doesn't work so well, since we have the opposite order potentially on queueing work. If POLL_ADD is used with a signalfd, then io_poll_wake() is called with the signal lock, and that sometimes needs to insert work items. Add a specific worker lock that protects the current work item. Then we can guarantee that the task we're sending a signal is currently processing the exact work we think it is. Reported-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-14 00:43:34 +08:00
spinlock_t lock;
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
struct rcu_head rcu;
struct mm_struct *mm;
io_uring: async workers should inherit the user creds If we don't inherit the original task creds, then we can confuse users like fuse that pass creds in the request header. See link below on identical aio issue. Link: https://lore.kernel.org/linux-fsdevel/26f0d78e-99ca-2f1b-78b9-433088053a61@scylladb.com/T/#u Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-25 23:52:30 +08:00
const struct cred *creds;
io_uring: io_uring: add support for async work inheriting files This is in preparation for adding opcodes that need to add new files in a process file table, system calls like open(2) or accept4(2). If an opcode needs this, it must set IO_WQ_WORK_NEEDS_FILES in the work item. If work that needs to get punted to async context have this set, the async worker will assume the original task file table before executing the work. Note that opcodes that need access to the current files of an application cannot be done through IORING_SETUP_SQPOLL. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-25 02:39:47 +08:00
struct files_struct *restore_files;
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
};
#if BITS_PER_LONG == 64
#define IO_WQ_HASH_ORDER 6
#else
#define IO_WQ_HASH_ORDER 5
#endif
io-wq: add support for bounded vs unbunded work io_uring supports request types that basically have two different lifetimes: 1) Bounded completion time. These are requests like disk reads or writes, which we know will finish in a finite amount of time. 2) Unbounded completion time. These are generally networked IO, where we have no idea how long they will take to complete. Another example is POLL commands. This patch provides support for io-wq to handle these differently, so we don't starve bounded requests by tying up workers for too long. By default all work is bounded, unless otherwise specified in the work item. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08 02:41:16 +08:00
struct io_wqe_acct {
unsigned nr_workers;
unsigned max_workers;
atomic_t nr_running;
};
enum {
IO_WQ_ACCT_BOUND,
IO_WQ_ACCT_UNBOUND,
};
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
/*
* Per-node worker thread pool
*/
struct io_wqe {
struct {
spinlock_t lock;
io-wq: shrink io_wq_work a bit Currently we're using 40 bytes for the io_wq_work structure, and 16 of those is the doubly link list node. We don't need doubly linked lists, we always add to tail to keep things ordered, and any other use case is list traversal with deletion. For the deletion case, we can easily support any node deletion by keeping track of the previous entry. This shrinks io_wq_work to 32 bytes, and subsequently io_kiock from io_uring to 216 to 208 bytes. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27 02:59:32 +08:00
struct io_wq_work_list work_list;
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
unsigned long hash_map;
unsigned flags;
} ____cacheline_aligned_in_smp;
int node;
io-wq: add support for bounded vs unbunded work io_uring supports request types that basically have two different lifetimes: 1) Bounded completion time. These are requests like disk reads or writes, which we know will finish in a finite amount of time. 2) Unbounded completion time. These are generally networked IO, where we have no idea how long they will take to complete. Another example is POLL commands. This patch provides support for io-wq to handle these differently, so we don't starve bounded requests by tying up workers for too long. By default all work is bounded, unless otherwise specified in the work item. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08 02:41:16 +08:00
struct io_wqe_acct acct[2];
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
io-wq: remove now redundant struct io_wq_nulls_list Since we don't iterate these lists anymore after commit: e61df66c69b1 ("io-wq: ensure free/busy list browsing see all items") we don't need to retain the nulls value we use for them. That means it's pretty pointless to wrap the hlist_nulls_head in a structure, so get rid of it. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-14 23:00:41 +08:00
struct hlist_nulls_head free_list;
struct hlist_nulls_head busy_list;
io-wq: ensure free/busy list browsing see all items We have two lists for workers in io-wq, a busy and a free list. For certain operations we want to browse all workers, and we currently do that by browsing the two separate lists. But since these lists are RCU protected, we can potentially miss workers if they move between the two lists while we're browsing them. Add a third list, all_list, that simply holds all workers. A worker is added to that list when it starts, and removed when it exits. This makes the worker iteration cleaner, too. Reported-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-14 04:54:49 +08:00
struct list_head all_list;
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
struct io_wq *wq;
};
/*
* Per io_wq state
*/
struct io_wq {
struct io_wqe **wqes;
unsigned long state;
io_wq: add get/put_work handlers to io_wq_create() For cancellation, we need to ensure that the work item stays valid for as long as ->cur_work is valid. Right now we can't safely dereference the work item even under the wqe->lock, because while the ->cur_work pointer will remain valid, the work could be completing and be freed in parallel. Only invoke ->get/put_work() on items we know that the caller queued themselves. Add IO_WQ_WORK_INTERNAL for io-wq to use, which is needed when we're queueing a flush item, for instance. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-13 13:31:31 +08:00
get_work_fn *get_work;
put_work_fn *put_work;
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
struct task_struct *manager;
io-wq: add support for bounded vs unbunded work io_uring supports request types that basically have two different lifetimes: 1) Bounded completion time. These are requests like disk reads or writes, which we know will finish in a finite amount of time. 2) Unbounded completion time. These are generally networked IO, where we have no idea how long they will take to complete. Another example is POLL commands. This patch provides support for io-wq to handle these differently, so we don't starve bounded requests by tying up workers for too long. By default all work is bounded, unless otherwise specified in the work item. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08 02:41:16 +08:00
struct user_struct *user;
io_uring: use current task creds instead of allocating a new one syzbot reports: kasan: CONFIG_KASAN_INLINE enabled kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 9217 Comm: io_uring-sq Not tainted 5.4.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:creds_are_invalid kernel/cred.c:792 [inline] RIP: 0010:__validate_creds include/linux/cred.h:187 [inline] RIP: 0010:override_creds+0x9f/0x170 kernel/cred.c:550 Code: ac 25 00 81 fb 64 65 73 43 0f 85 a3 37 00 00 e8 17 ab 25 00 49 8d 7c 24 10 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 96 00 00 00 41 8b 5c 24 10 bf RSP: 0018:ffff88809c45fda0 EFLAGS: 00010202 RAX: dffffc0000000000 RBX: 0000000043736564 RCX: ffffffff814f3318 RDX: 0000000000000002 RSI: ffffffff814f3329 RDI: 0000000000000010 RBP: ffff88809c45fdb8 R08: ffff8880a3aac240 R09: ffffed1014755849 R10: ffffed1014755848 R11: ffff8880a3aac247 R12: 0000000000000000 R13: ffff888098ab1600 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffd51c40664 CR3: 0000000092641000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: io_sq_thread+0x1c7/0xa20 fs/io_uring.c:3274 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Modules linked in: ---[ end trace f2e1a4307fbe2245 ]--- RIP: 0010:creds_are_invalid kernel/cred.c:792 [inline] RIP: 0010:__validate_creds include/linux/cred.h:187 [inline] RIP: 0010:override_creds+0x9f/0x170 kernel/cred.c:550 Code: ac 25 00 81 fb 64 65 73 43 0f 85 a3 37 00 00 e8 17 ab 25 00 49 8d 7c 24 10 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 96 00 00 00 41 8b 5c 24 10 bf RSP: 0018:ffff88809c45fda0 EFLAGS: 00010202 RAX: dffffc0000000000 RBX: 0000000043736564 RCX: ffffffff814f3318 RDX: 0000000000000002 RSI: ffffffff814f3329 RDI: 0000000000000010 RBP: ffff88809c45fdb8 R08: ffff8880a3aac240 R09: ffffed1014755849 R10: ffffed1014755848 R11: ffff8880a3aac247 R12: 0000000000000000 R13: ffff888098ab1600 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffd51c40664 CR3: 0000000092641000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 which is caused by slab fault injection triggering a failure in prepare_creds(). We don't actually need to create a copy of the creds as we're not modifying it, we just need a reference on the current task creds. This avoids the failure case as well, and propagates the const throughout the stack. Fixes: 181e448d8709 ("io_uring: async workers should inherit the user creds") Reported-by: syzbot+5320383e16029ba057ff@syzkaller.appspotmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-12-02 23:50:00 +08:00
const struct cred *creds;
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
struct mm_struct *mm;
refcount_t refs;
struct completion done;
};
static bool io_worker_get(struct io_worker *worker)
{
return refcount_inc_not_zero(&worker->ref);
}
static void io_worker_release(struct io_worker *worker)
{
if (refcount_dec_and_test(&worker->ref))
wake_up_process(worker->task);
}
/*
* Note: drops the wqe->lock if returning true! The caller must re-acquire
* the lock in that case. Some callers need to restart handling if this
* happens, so we can't just re-acquire the lock on behalf of the caller.
*/
static bool __io_worker_unuse(struct io_wqe *wqe, struct io_worker *worker)
{
io_uring: io_uring: add support for async work inheriting files This is in preparation for adding opcodes that need to add new files in a process file table, system calls like open(2) or accept4(2). If an opcode needs this, it must set IO_WQ_WORK_NEEDS_FILES in the work item. If work that needs to get punted to async context have this set, the async worker will assume the original task file table before executing the work. Note that opcodes that need access to the current files of an application cannot be done through IORING_SETUP_SQPOLL. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-25 02:39:47 +08:00
bool dropped_lock = false;
io_uring: async workers should inherit the user creds If we don't inherit the original task creds, then we can confuse users like fuse that pass creds in the request header. See link below on identical aio issue. Link: https://lore.kernel.org/linux-fsdevel/26f0d78e-99ca-2f1b-78b9-433088053a61@scylladb.com/T/#u Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-25 23:52:30 +08:00
if (worker->creds) {
revert_creds(worker->creds);
worker->creds = NULL;
}
io_uring: io_uring: add support for async work inheriting files This is in preparation for adding opcodes that need to add new files in a process file table, system calls like open(2) or accept4(2). If an opcode needs this, it must set IO_WQ_WORK_NEEDS_FILES in the work item. If work that needs to get punted to async context have this set, the async worker will assume the original task file table before executing the work. Note that opcodes that need access to the current files of an application cannot be done through IORING_SETUP_SQPOLL. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-25 02:39:47 +08:00
if (current->files != worker->restore_files) {
__acquire(&wqe->lock);
spin_unlock_irq(&wqe->lock);
dropped_lock = true;
task_lock(current);
current->files = worker->restore_files;
task_unlock(current);
}
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
/*
* If we have an active mm, we need to drop the wq lock before unusing
* it. If we do, return true and let the caller retry the idle loop.
*/
if (worker->mm) {
io_uring: io_uring: add support for async work inheriting files This is in preparation for adding opcodes that need to add new files in a process file table, system calls like open(2) or accept4(2). If an opcode needs this, it must set IO_WQ_WORK_NEEDS_FILES in the work item. If work that needs to get punted to async context have this set, the async worker will assume the original task file table before executing the work. Note that opcodes that need access to the current files of an application cannot be done through IORING_SETUP_SQPOLL. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-25 02:39:47 +08:00
if (!dropped_lock) {
__acquire(&wqe->lock);
spin_unlock_irq(&wqe->lock);
dropped_lock = true;
}
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
__set_current_state(TASK_RUNNING);
set_fs(KERNEL_DS);
unuse_mm(worker->mm);
mmput(worker->mm);
worker->mm = NULL;
}
io_uring: io_uring: add support for async work inheriting files This is in preparation for adding opcodes that need to add new files in a process file table, system calls like open(2) or accept4(2). If an opcode needs this, it must set IO_WQ_WORK_NEEDS_FILES in the work item. If work that needs to get punted to async context have this set, the async worker will assume the original task file table before executing the work. Note that opcodes that need access to the current files of an application cannot be done through IORING_SETUP_SQPOLL. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-25 02:39:47 +08:00
return dropped_lock;
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
}
io-wq: add support for bounded vs unbunded work io_uring supports request types that basically have two different lifetimes: 1) Bounded completion time. These are requests like disk reads or writes, which we know will finish in a finite amount of time. 2) Unbounded completion time. These are generally networked IO, where we have no idea how long they will take to complete. Another example is POLL commands. This patch provides support for io-wq to handle these differently, so we don't starve bounded requests by tying up workers for too long. By default all work is bounded, unless otherwise specified in the work item. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08 02:41:16 +08:00
static inline struct io_wqe_acct *io_work_get_acct(struct io_wqe *wqe,
struct io_wq_work *work)
{
if (work->flags & IO_WQ_WORK_UNBOUND)
return &wqe->acct[IO_WQ_ACCT_UNBOUND];
return &wqe->acct[IO_WQ_ACCT_BOUND];
}
static inline struct io_wqe_acct *io_wqe_get_acct(struct io_wqe *wqe,
struct io_worker *worker)
{
if (worker->flags & IO_WORKER_F_BOUND)
return &wqe->acct[IO_WQ_ACCT_BOUND];
return &wqe->acct[IO_WQ_ACCT_UNBOUND];
}
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
static void io_worker_exit(struct io_worker *worker)
{
struct io_wqe *wqe = worker->wqe;
io-wq: add support for bounded vs unbunded work io_uring supports request types that basically have two different lifetimes: 1) Bounded completion time. These are requests like disk reads or writes, which we know will finish in a finite amount of time. 2) Unbounded completion time. These are generally networked IO, where we have no idea how long they will take to complete. Another example is POLL commands. This patch provides support for io-wq to handle these differently, so we don't starve bounded requests by tying up workers for too long. By default all work is bounded, unless otherwise specified in the work item. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08 02:41:16 +08:00
struct io_wqe_acct *acct = io_wqe_get_acct(wqe, worker);
unsigned nr_workers;
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
/*
* If we're not at zero, someone else is holding a brief reference
* to the worker. Wait for that to go away.
*/
set_current_state(TASK_INTERRUPTIBLE);
if (!refcount_dec_and_test(&worker->ref))
schedule();
__set_current_state(TASK_RUNNING);
preempt_disable();
current->flags &= ~PF_IO_WORKER;
if (worker->flags & IO_WORKER_F_RUNNING)
io-wq: add support for bounded vs unbunded work io_uring supports request types that basically have two different lifetimes: 1) Bounded completion time. These are requests like disk reads or writes, which we know will finish in a finite amount of time. 2) Unbounded completion time. These are generally networked IO, where we have no idea how long they will take to complete. Another example is POLL commands. This patch provides support for io-wq to handle these differently, so we don't starve bounded requests by tying up workers for too long. By default all work is bounded, unless otherwise specified in the work item. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08 02:41:16 +08:00
atomic_dec(&acct->nr_running);
if (!(worker->flags & IO_WORKER_F_BOUND))
atomic_dec(&wqe->wq->user->processes);
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
worker->flags = 0;
preempt_enable();
spin_lock_irq(&wqe->lock);
hlist_nulls_del_rcu(&worker->nulls_node);
io-wq: ensure free/busy list browsing see all items We have two lists for workers in io-wq, a busy and a free list. For certain operations we want to browse all workers, and we currently do that by browsing the two separate lists. But since these lists are RCU protected, we can potentially miss workers if they move between the two lists while we're browsing them. Add a third list, all_list, that simply holds all workers. A worker is added to that list when it starts, and removed when it exits. This makes the worker iteration cleaner, too. Reported-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-14 04:54:49 +08:00
list_del_rcu(&worker->all_list);
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
if (__io_worker_unuse(wqe, worker)) {
__release(&wqe->lock);
spin_lock_irq(&wqe->lock);
}
io-wq: add support for bounded vs unbunded work io_uring supports request types that basically have two different lifetimes: 1) Bounded completion time. These are requests like disk reads or writes, which we know will finish in a finite amount of time. 2) Unbounded completion time. These are generally networked IO, where we have no idea how long they will take to complete. Another example is POLL commands. This patch provides support for io-wq to handle these differently, so we don't starve bounded requests by tying up workers for too long. By default all work is bounded, unless otherwise specified in the work item. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08 02:41:16 +08:00
acct->nr_workers--;
nr_workers = wqe->acct[IO_WQ_ACCT_BOUND].nr_workers +
wqe->acct[IO_WQ_ACCT_UNBOUND].nr_workers;
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
spin_unlock_irq(&wqe->lock);
/* all workers gone, wq exit can proceed */
io-wq: add support for bounded vs unbunded work io_uring supports request types that basically have two different lifetimes: 1) Bounded completion time. These are requests like disk reads or writes, which we know will finish in a finite amount of time. 2) Unbounded completion time. These are generally networked IO, where we have no idea how long they will take to complete. Another example is POLL commands. This patch provides support for io-wq to handle these differently, so we don't starve bounded requests by tying up workers for too long. By default all work is bounded, unless otherwise specified in the work item. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08 02:41:16 +08:00
if (!nr_workers && refcount_dec_and_test(&wqe->wq->refs))
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
complete(&wqe->wq->done);
io-wq: use kfree_rcu() to simplify the code The callback function of call_rcu() just calls kfree(), so we can use kfree_rcu() instead of call_rcu() + callback function. Signed-off-by: YueHaibing <yuehaibing@huawei.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-02 15:55:01 +08:00
kfree_rcu(worker, rcu);
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
}
io-wq: add support for bounded vs unbunded work io_uring supports request types that basically have two different lifetimes: 1) Bounded completion time. These are requests like disk reads or writes, which we know will finish in a finite amount of time. 2) Unbounded completion time. These are generally networked IO, where we have no idea how long they will take to complete. Another example is POLL commands. This patch provides support for io-wq to handle these differently, so we don't starve bounded requests by tying up workers for too long. By default all work is bounded, unless otherwise specified in the work item. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08 02:41:16 +08:00
static inline bool io_wqe_run_queue(struct io_wqe *wqe)
__must_hold(wqe->lock)
{
io-wq: shrink io_wq_work a bit Currently we're using 40 bytes for the io_wq_work structure, and 16 of those is the doubly link list node. We don't need doubly linked lists, we always add to tail to keep things ordered, and any other use case is list traversal with deletion. For the deletion case, we can easily support any node deletion by keeping track of the previous entry. This shrinks io_wq_work to 32 bytes, and subsequently io_kiock from io_uring to 216 to 208 bytes. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27 02:59:32 +08:00
if (!wq_list_empty(&wqe->work_list) &&
!(wqe->flags & IO_WQE_FLAG_STALLED))
io-wq: add support for bounded vs unbunded work io_uring supports request types that basically have two different lifetimes: 1) Bounded completion time. These are requests like disk reads or writes, which we know will finish in a finite amount of time. 2) Unbounded completion time. These are generally networked IO, where we have no idea how long they will take to complete. Another example is POLL commands. This patch provides support for io-wq to handle these differently, so we don't starve bounded requests by tying up workers for too long. By default all work is bounded, unless otherwise specified in the work item. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08 02:41:16 +08:00
return true;
return false;
}
/*
* Check head of free list for an available worker. If one isn't available,
* caller must wake up the wq manager to create one.
*/
static bool io_wqe_activate_free_worker(struct io_wqe *wqe)
__must_hold(RCU)
{
struct hlist_nulls_node *n;
struct io_worker *worker;
io-wq: remove now redundant struct io_wq_nulls_list Since we don't iterate these lists anymore after commit: e61df66c69b1 ("io-wq: ensure free/busy list browsing see all items") we don't need to retain the nulls value we use for them. That means it's pretty pointless to wrap the hlist_nulls_head in a structure, so get rid of it. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-14 23:00:41 +08:00
n = rcu_dereference(hlist_nulls_first_rcu(&wqe->free_list));
io-wq: add support for bounded vs unbunded work io_uring supports request types that basically have two different lifetimes: 1) Bounded completion time. These are requests like disk reads or writes, which we know will finish in a finite amount of time. 2) Unbounded completion time. These are generally networked IO, where we have no idea how long they will take to complete. Another example is POLL commands. This patch provides support for io-wq to handle these differently, so we don't starve bounded requests by tying up workers for too long. By default all work is bounded, unless otherwise specified in the work item. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08 02:41:16 +08:00
if (is_a_nulls(n))
return false;
worker = hlist_nulls_entry(n, struct io_worker, nulls_node);
if (io_worker_get(worker)) {
wake_up(&worker->wait);
io_worker_release(worker);
return true;
}
return false;
}
/*
* We need a worker. If we find a free one, we're good. If not, and we're
* below the max number of workers, wake up the manager to create one.
*/
static void io_wqe_wake_worker(struct io_wqe *wqe, struct io_wqe_acct *acct)
{
bool ret;
/*
* Most likely an attempt to queue unbounded work on an io_wq that
* wasn't setup with any unbounded workers.
*/
WARN_ON_ONCE(!acct->max_workers);
rcu_read_lock();
ret = io_wqe_activate_free_worker(wqe);
rcu_read_unlock();
if (!ret && acct->nr_workers < acct->max_workers)
wake_up_process(wqe->wq->manager);
}
static void io_wqe_inc_running(struct io_wqe *wqe, struct io_worker *worker)
{
struct io_wqe_acct *acct = io_wqe_get_acct(wqe, worker);
atomic_inc(&acct->nr_running);
}
static void io_wqe_dec_running(struct io_wqe *wqe, struct io_worker *worker)
__must_hold(wqe->lock)
{
struct io_wqe_acct *acct = io_wqe_get_acct(wqe, worker);
if (atomic_dec_and_test(&acct->nr_running) && io_wqe_run_queue(wqe))
io_wqe_wake_worker(wqe, acct);
}
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
static void io_worker_start(struct io_wqe *wqe, struct io_worker *worker)
{
allow_kernel_signal(SIGINT);
current->flags |= PF_IO_WORKER;
worker->flags |= (IO_WORKER_F_UP | IO_WORKER_F_RUNNING);
io_uring: io_uring: add support for async work inheriting files This is in preparation for adding opcodes that need to add new files in a process file table, system calls like open(2) or accept4(2). If an opcode needs this, it must set IO_WQ_WORK_NEEDS_FILES in the work item. If work that needs to get punted to async context have this set, the async worker will assume the original task file table before executing the work. Note that opcodes that need access to the current files of an application cannot be done through IORING_SETUP_SQPOLL. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-25 02:39:47 +08:00
worker->restore_files = current->files;
io-wq: add support for bounded vs unbunded work io_uring supports request types that basically have two different lifetimes: 1) Bounded completion time. These are requests like disk reads or writes, which we know will finish in a finite amount of time. 2) Unbounded completion time. These are generally networked IO, where we have no idea how long they will take to complete. Another example is POLL commands. This patch provides support for io-wq to handle these differently, so we don't starve bounded requests by tying up workers for too long. By default all work is bounded, unless otherwise specified in the work item. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08 02:41:16 +08:00
io_wqe_inc_running(wqe, worker);
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
}
/*
* Worker will start processing some work. Move it to the busy list, if
* it's currently on the freelist
*/
static void __io_worker_busy(struct io_wqe *wqe, struct io_worker *worker,
struct io_wq_work *work)
__must_hold(wqe->lock)
{
io-wq: add support for bounded vs unbunded work io_uring supports request types that basically have two different lifetimes: 1) Bounded completion time. These are requests like disk reads or writes, which we know will finish in a finite amount of time. 2) Unbounded completion time. These are generally networked IO, where we have no idea how long they will take to complete. Another example is POLL commands. This patch provides support for io-wq to handle these differently, so we don't starve bounded requests by tying up workers for too long. By default all work is bounded, unless otherwise specified in the work item. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08 02:41:16 +08:00
bool worker_bound, work_bound;
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
if (worker->flags & IO_WORKER_F_FREE) {
worker->flags &= ~IO_WORKER_F_FREE;
hlist_nulls_del_init_rcu(&worker->nulls_node);
io-wq: remove now redundant struct io_wq_nulls_list Since we don't iterate these lists anymore after commit: e61df66c69b1 ("io-wq: ensure free/busy list browsing see all items") we don't need to retain the nulls value we use for them. That means it's pretty pointless to wrap the hlist_nulls_head in a structure, so get rid of it. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-14 23:00:41 +08:00
hlist_nulls_add_head_rcu(&worker->nulls_node, &wqe->busy_list);
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
}
io-wq: add support for bounded vs unbunded work io_uring supports request types that basically have two different lifetimes: 1) Bounded completion time. These are requests like disk reads or writes, which we know will finish in a finite amount of time. 2) Unbounded completion time. These are generally networked IO, where we have no idea how long they will take to complete. Another example is POLL commands. This patch provides support for io-wq to handle these differently, so we don't starve bounded requests by tying up workers for too long. By default all work is bounded, unless otherwise specified in the work item. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08 02:41:16 +08:00
/*
* If worker is moving from bound to unbound (or vice versa), then
* ensure we update the running accounting.
*/
io-wq: remove extra space characters These lines are indented an extra space character. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-19 14:22:16 +08:00
worker_bound = (worker->flags & IO_WORKER_F_BOUND) != 0;
work_bound = (work->flags & IO_WQ_WORK_UNBOUND) == 0;
if (worker_bound != work_bound) {
io-wq: add support for bounded vs unbunded work io_uring supports request types that basically have two different lifetimes: 1) Bounded completion time. These are requests like disk reads or writes, which we know will finish in a finite amount of time. 2) Unbounded completion time. These are generally networked IO, where we have no idea how long they will take to complete. Another example is POLL commands. This patch provides support for io-wq to handle these differently, so we don't starve bounded requests by tying up workers for too long. By default all work is bounded, unless otherwise specified in the work item. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08 02:41:16 +08:00
io_wqe_dec_running(wqe, worker);
if (work_bound) {
worker->flags |= IO_WORKER_F_BOUND;
wqe->acct[IO_WQ_ACCT_UNBOUND].nr_workers--;
wqe->acct[IO_WQ_ACCT_BOUND].nr_workers++;
atomic_dec(&wqe->wq->user->processes);
} else {
worker->flags &= ~IO_WORKER_F_BOUND;
wqe->acct[IO_WQ_ACCT_UNBOUND].nr_workers++;
wqe->acct[IO_WQ_ACCT_BOUND].nr_workers--;
atomic_inc(&wqe->wq->user->processes);
}
io_wqe_inc_running(wqe, worker);
}
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
}
/*
* No work, worker going to sleep. Move to freelist, and unuse mm if we
* have one attached. Dropping the mm may potentially sleep, so we drop
* the lock in that case and return success. Since the caller has to
* retry the loop in that case (we changed task state), we don't regrab
* the lock if we return success.
*/
static bool __io_worker_idle(struct io_wqe *wqe, struct io_worker *worker)
__must_hold(wqe->lock)
{
if (!(worker->flags & IO_WORKER_F_FREE)) {
worker->flags |= IO_WORKER_F_FREE;
hlist_nulls_del_init_rcu(&worker->nulls_node);
io-wq: remove now redundant struct io_wq_nulls_list Since we don't iterate these lists anymore after commit: e61df66c69b1 ("io-wq: ensure free/busy list browsing see all items") we don't need to retain the nulls value we use for them. That means it's pretty pointless to wrap the hlist_nulls_head in a structure, so get rid of it. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-14 23:00:41 +08:00
hlist_nulls_add_head_rcu(&worker->nulls_node, &wqe->free_list);
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
}
return __io_worker_unuse(wqe, worker);
}
static struct io_wq_work *io_get_next_work(struct io_wqe *wqe, unsigned *hash)
__must_hold(wqe->lock)
{
io-wq: shrink io_wq_work a bit Currently we're using 40 bytes for the io_wq_work structure, and 16 of those is the doubly link list node. We don't need doubly linked lists, we always add to tail to keep things ordered, and any other use case is list traversal with deletion. For the deletion case, we can easily support any node deletion by keeping track of the previous entry. This shrinks io_wq_work to 32 bytes, and subsequently io_kiock from io_uring to 216 to 208 bytes. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27 02:59:32 +08:00
struct io_wq_work_node *node, *prev;
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
struct io_wq_work *work;
io-wq: shrink io_wq_work a bit Currently we're using 40 bytes for the io_wq_work structure, and 16 of those is the doubly link list node. We don't need doubly linked lists, we always add to tail to keep things ordered, and any other use case is list traversal with deletion. For the deletion case, we can easily support any node deletion by keeping track of the previous entry. This shrinks io_wq_work to 32 bytes, and subsequently io_kiock from io_uring to 216 to 208 bytes. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27 02:59:32 +08:00
wq_list_for_each(node, prev, &wqe->work_list) {
work = container_of(node, struct io_wq_work, list);
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
/* not hashed, can run anytime */
if (!(work->flags & IO_WQ_WORK_HASHED)) {
io-wq: shrink io_wq_work a bit Currently we're using 40 bytes for the io_wq_work structure, and 16 of those is the doubly link list node. We don't need doubly linked lists, we always add to tail to keep things ordered, and any other use case is list traversal with deletion. For the deletion case, we can easily support any node deletion by keeping track of the previous entry. This shrinks io_wq_work to 32 bytes, and subsequently io_kiock from io_uring to 216 to 208 bytes. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27 02:59:32 +08:00
wq_node_del(&wqe->work_list, node, prev);
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
return work;
}
/* hashed, can run if not already running */
*hash = work->flags >> IO_WQ_HASH_SHIFT;
if (!(wqe->hash_map & BIT_ULL(*hash))) {
wqe->hash_map |= BIT_ULL(*hash);
io-wq: shrink io_wq_work a bit Currently we're using 40 bytes for the io_wq_work structure, and 16 of those is the doubly link list node. We don't need doubly linked lists, we always add to tail to keep things ordered, and any other use case is list traversal with deletion. For the deletion case, we can easily support any node deletion by keeping track of the previous entry. This shrinks io_wq_work to 32 bytes, and subsequently io_kiock from io_uring to 216 to 208 bytes. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27 02:59:32 +08:00
wq_node_del(&wqe->work_list, node, prev);
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
return work;
}
}
return NULL;
}
static void io_worker_handle_work(struct io_worker *worker)
__releases(wqe->lock)
{
io_wq: add get/put_work handlers to io_wq_create() For cancellation, we need to ensure that the work item stays valid for as long as ->cur_work is valid. Right now we can't safely dereference the work item even under the wqe->lock, because while the ->cur_work pointer will remain valid, the work could be completing and be freed in parallel. Only invoke ->get/put_work() on items we know that the caller queued themselves. Add IO_WQ_WORK_INTERNAL for io-wq to use, which is needed when we're queueing a flush item, for instance. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-13 13:31:31 +08:00
struct io_wq_work *work, *old_work = NULL, *put_work = NULL;
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
struct io_wqe *wqe = worker->wqe;
struct io_wq *wq = wqe->wq;
do {
unsigned hash = -1U;
/*
* If we got some work, mark us as busy. If we didn't, but
* the list isn't empty, it means we stalled on hashed work.
* Mark us stalled so we don't keep looking for work when we
* can't make progress, any work completion or insertion will
* clear the stalled flag.
*/
work = io_get_next_work(wqe, &hash);
if (work)
__io_worker_busy(wqe, worker, work);
io-wq: shrink io_wq_work a bit Currently we're using 40 bytes for the io_wq_work structure, and 16 of those is the doubly link list node. We don't need doubly linked lists, we always add to tail to keep things ordered, and any other use case is list traversal with deletion. For the deletion case, we can easily support any node deletion by keeping track of the previous entry. This shrinks io_wq_work to 32 bytes, and subsequently io_kiock from io_uring to 216 to 208 bytes. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27 02:59:32 +08:00
else if (!wq_list_empty(&wqe->work_list))
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
wqe->flags |= IO_WQE_FLAG_STALLED;
spin_unlock_irq(&wqe->lock);
io_wq: add get/put_work handlers to io_wq_create() For cancellation, we need to ensure that the work item stays valid for as long as ->cur_work is valid. Right now we can't safely dereference the work item even under the wqe->lock, because while the ->cur_work pointer will remain valid, the work could be completing and be freed in parallel. Only invoke ->get/put_work() on items we know that the caller queued themselves. Add IO_WQ_WORK_INTERNAL for io-wq to use, which is needed when we're queueing a flush item, for instance. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-13 13:31:31 +08:00
if (put_work && wq->put_work)
wq->put_work(old_work);
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
if (!work)
break;
next:
io-wq: ensure we have a stable view of ->cur_work for cancellations worker->cur_work is currently protected by the lock of the wqe that the worker belongs to. When we send a signal to a worker, we need a stable view of ->cur_work, so we need to hold that lock. But this doesn't work so well, since we have the opposite order potentially on queueing work. If POLL_ADD is used with a signalfd, then io_poll_wake() is called with the signal lock, and that sometimes needs to insert work items. Add a specific worker lock that protects the current work item. Then we can guarantee that the task we're sending a signal is currently processing the exact work we think it is. Reported-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-14 00:43:34 +08:00
/* flush any pending signals before assigning new work */
if (signal_pending(current))
flush_signals(current);
spin_lock_irq(&worker->lock);
worker->cur_work = work;
spin_unlock_irq(&worker->lock);
io_uring: close lookup gap for dependent next work When we find new work to process within the work handler, we queue the linked timeout before we have issued the new work. This can be problematic for very short timeouts, as we have a window where the new work isn't visible. Allow the work handler to store a callback function for this in the work item, and flag it with IO_WQ_WORK_CB if the caller has done so. If that is set, then io-wq will call the callback when it has setup the new work item. Reported-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-21 04:05:32 +08:00
if (work->flags & IO_WQ_WORK_CB)
work->func(&work);
io_uring: io_uring: add support for async work inheriting files This is in preparation for adding opcodes that need to add new files in a process file table, system calls like open(2) or accept4(2). If an opcode needs this, it must set IO_WQ_WORK_NEEDS_FILES in the work item. If work that needs to get punted to async context have this set, the async worker will assume the original task file table before executing the work. Note that opcodes that need access to the current files of an application cannot be done through IORING_SETUP_SQPOLL. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-25 02:39:47 +08:00
if ((work->flags & IO_WQ_WORK_NEEDS_FILES) &&
current->files != work->files) {
task_lock(current);
current->files = work->files;
task_unlock(current);
}
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
if ((work->flags & IO_WQ_WORK_NEEDS_USER) && !worker->mm &&
wq->mm && mmget_not_zero(wq->mm)) {
use_mm(wq->mm);
set_fs(USER_DS);
worker->mm = wq->mm;
}
io_uring: async workers should inherit the user creds If we don't inherit the original task creds, then we can confuse users like fuse that pass creds in the request header. See link below on identical aio issue. Link: https://lore.kernel.org/linux-fsdevel/26f0d78e-99ca-2f1b-78b9-433088053a61@scylladb.com/T/#u Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-25 23:52:30 +08:00
if (!worker->creds)
worker->creds = override_creds(wq->creds);
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
if (test_bit(IO_WQ_BIT_CANCEL, &wq->state))
work->flags |= IO_WQ_WORK_CANCEL;
if (worker->mm)
work->flags |= IO_WQ_WORK_HAS_MM;
io_wq: add get/put_work handlers to io_wq_create() For cancellation, we need to ensure that the work item stays valid for as long as ->cur_work is valid. Right now we can't safely dereference the work item even under the wqe->lock, because while the ->cur_work pointer will remain valid, the work could be completing and be freed in parallel. Only invoke ->get/put_work() on items we know that the caller queued themselves. Add IO_WQ_WORK_INTERNAL for io-wq to use, which is needed when we're queueing a flush item, for instance. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-13 13:31:31 +08:00
if (wq->get_work && !(work->flags & IO_WQ_WORK_INTERNAL)) {
put_work = work;
wq->get_work(work);
}
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
old_work = work;
work->func(&work);
io-wq: ensure we have a stable view of ->cur_work for cancellations worker->cur_work is currently protected by the lock of the wqe that the worker belongs to. When we send a signal to a worker, we need a stable view of ->cur_work, so we need to hold that lock. But this doesn't work so well, since we have the opposite order potentially on queueing work. If POLL_ADD is used with a signalfd, then io_poll_wake() is called with the signal lock, and that sometimes needs to insert work items. Add a specific worker lock that protects the current work item. Then we can guarantee that the task we're sending a signal is currently processing the exact work we think it is. Reported-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-14 00:43:34 +08:00
spin_lock_irq(&worker->lock);
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
worker->cur_work = NULL;
io-wq: ensure we have a stable view of ->cur_work for cancellations worker->cur_work is currently protected by the lock of the wqe that the worker belongs to. When we send a signal to a worker, we need a stable view of ->cur_work, so we need to hold that lock. But this doesn't work so well, since we have the opposite order potentially on queueing work. If POLL_ADD is used with a signalfd, then io_poll_wake() is called with the signal lock, and that sometimes needs to insert work items. Add a specific worker lock that protects the current work item. Then we can guarantee that the task we're sending a signal is currently processing the exact work we think it is. Reported-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-14 00:43:34 +08:00
spin_unlock_irq(&worker->lock);
spin_lock_irq(&wqe->lock);
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
if (hash != -1U) {
wqe->hash_map &= ~BIT_ULL(hash);
wqe->flags &= ~IO_WQE_FLAG_STALLED;
}
if (work && work != old_work) {
spin_unlock_irq(&wqe->lock);
io_wq: add get/put_work handlers to io_wq_create() For cancellation, we need to ensure that the work item stays valid for as long as ->cur_work is valid. Right now we can't safely dereference the work item even under the wqe->lock, because while the ->cur_work pointer will remain valid, the work could be completing and be freed in parallel. Only invoke ->get/put_work() on items we know that the caller queued themselves. Add IO_WQ_WORK_INTERNAL for io-wq to use, which is needed when we're queueing a flush item, for instance. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-13 13:31:31 +08:00
if (put_work && wq->put_work) {
wq->put_work(put_work);
put_work = NULL;
}
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
/* dependent work not hashed */
hash = -1U;
goto next;
}
} while (1);
}
static int io_wqe_worker(void *data)
{
struct io_worker *worker = data;
struct io_wqe *wqe = worker->wqe;
struct io_wq *wq = wqe->wq;
DEFINE_WAIT(wait);
io_worker_start(wqe, worker);
while (!test_bit(IO_WQ_BIT_EXIT, &wq->state)) {
prepare_to_wait(&worker->wait, &wait, TASK_INTERRUPTIBLE);
spin_lock_irq(&wqe->lock);
if (io_wqe_run_queue(wqe)) {
__set_current_state(TASK_RUNNING);
io_worker_handle_work(worker);
continue;
}
/* drops the lock on success, retry */
if (__io_worker_idle(wqe, worker)) {
__release(&wqe->lock);
continue;
}
spin_unlock_irq(&wqe->lock);
if (signal_pending(current))
flush_signals(current);
if (schedule_timeout(WORKER_IDLE_TIMEOUT))
continue;
/* timed out, exit unless we're the fixed worker */
if (test_bit(IO_WQ_BIT_EXIT, &wq->state) ||
!(worker->flags & IO_WORKER_F_FIXED))
break;
}
finish_wait(&worker->wait, &wait);
if (test_bit(IO_WQ_BIT_EXIT, &wq->state)) {
spin_lock_irq(&wqe->lock);
io-wq: shrink io_wq_work a bit Currently we're using 40 bytes for the io_wq_work structure, and 16 of those is the doubly link list node. We don't need doubly linked lists, we always add to tail to keep things ordered, and any other use case is list traversal with deletion. For the deletion case, we can easily support any node deletion by keeping track of the previous entry. This shrinks io_wq_work to 32 bytes, and subsequently io_kiock from io_uring to 216 to 208 bytes. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27 02:59:32 +08:00
if (!wq_list_empty(&wqe->work_list))
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
io_worker_handle_work(worker);
else
spin_unlock_irq(&wqe->lock);
}
io_worker_exit(worker);
return 0;
}
/*
* Called when a worker is scheduled in. Mark us as currently running.
*/
void io_wq_worker_running(struct task_struct *tsk)
{
struct io_worker *worker = kthread_data(tsk);
struct io_wqe *wqe = worker->wqe;
if (!(worker->flags & IO_WORKER_F_UP))
return;
if (worker->flags & IO_WORKER_F_RUNNING)
return;
worker->flags |= IO_WORKER_F_RUNNING;
io-wq: add support for bounded vs unbunded work io_uring supports request types that basically have two different lifetimes: 1) Bounded completion time. These are requests like disk reads or writes, which we know will finish in a finite amount of time. 2) Unbounded completion time. These are generally networked IO, where we have no idea how long they will take to complete. Another example is POLL commands. This patch provides support for io-wq to handle these differently, so we don't starve bounded requests by tying up workers for too long. By default all work is bounded, unless otherwise specified in the work item. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08 02:41:16 +08:00
io_wqe_inc_running(wqe, worker);
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
}
/*
* Called when worker is going to sleep. If there are no workers currently
* running and we have work pending, wake up a free one or have the manager
* set one up.
*/
void io_wq_worker_sleeping(struct task_struct *tsk)
{
struct io_worker *worker = kthread_data(tsk);
struct io_wqe *wqe = worker->wqe;
if (!(worker->flags & IO_WORKER_F_UP))
return;
if (!(worker->flags & IO_WORKER_F_RUNNING))
return;
worker->flags &= ~IO_WORKER_F_RUNNING;
spin_lock_irq(&wqe->lock);
io-wq: add support for bounded vs unbunded work io_uring supports request types that basically have two different lifetimes: 1) Bounded completion time. These are requests like disk reads or writes, which we know will finish in a finite amount of time. 2) Unbounded completion time. These are generally networked IO, where we have no idea how long they will take to complete. Another example is POLL commands. This patch provides support for io-wq to handle these differently, so we don't starve bounded requests by tying up workers for too long. By default all work is bounded, unless otherwise specified in the work item. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08 02:41:16 +08:00
io_wqe_dec_running(wqe, worker);
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
spin_unlock_irq(&wqe->lock);
}
io-wq: wait for io_wq_create() to setup necessary workers We currently have a race where if setup is really slow, we can be calling io_wq_destroy() before we're done setting up. This will cause the caller to get stuck waiting for the manager to set things up, but the manager already exited. Fix this by doing a sync setup of the manager. This also fixes the case where if we failed creating workers, we'd also get stuck. In practice this race window was really small, as we already wait for the manager to start. Hence someone would have to call io_wq_destroy() after the task has started, but before it started the first loop. The reported test case forked tons of these, which is why it became an issue. Reported-by: syzbot+0f1cc17f85154f400465@syzkaller.appspotmail.com Fixes: 771b53d033e8 ("io-wq: small threadpool implementation for io_uring") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-19 23:37:07 +08:00
static bool create_io_worker(struct io_wq *wq, struct io_wqe *wqe, int index)
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
{
io-wq: add support for bounded vs unbunded work io_uring supports request types that basically have two different lifetimes: 1) Bounded completion time. These are requests like disk reads or writes, which we know will finish in a finite amount of time. 2) Unbounded completion time. These are generally networked IO, where we have no idea how long they will take to complete. Another example is POLL commands. This patch provides support for io-wq to handle these differently, so we don't starve bounded requests by tying up workers for too long. By default all work is bounded, unless otherwise specified in the work item. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08 02:41:16 +08:00
struct io_wqe_acct *acct =&wqe->acct[index];
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
struct io_worker *worker;
io_uring: use kzalloc instead of kcalloc for single-element allocations These allocations are single-element allocations, so don't use the array allocation wrapper for them. Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27 00:39:45 +08:00
worker = kzalloc_node(sizeof(*worker), GFP_KERNEL, wqe->node);
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
if (!worker)
io-wq: wait for io_wq_create() to setup necessary workers We currently have a race where if setup is really slow, we can be calling io_wq_destroy() before we're done setting up. This will cause the caller to get stuck waiting for the manager to set things up, but the manager already exited. Fix this by doing a sync setup of the manager. This also fixes the case where if we failed creating workers, we'd also get stuck. In practice this race window was really small, as we already wait for the manager to start. Hence someone would have to call io_wq_destroy() after the task has started, but before it started the first loop. The reported test case forked tons of these, which is why it became an issue. Reported-by: syzbot+0f1cc17f85154f400465@syzkaller.appspotmail.com Fixes: 771b53d033e8 ("io-wq: small threadpool implementation for io_uring") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-19 23:37:07 +08:00
return false;
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
refcount_set(&worker->ref, 1);
worker->nulls_node.pprev = NULL;
init_waitqueue_head(&worker->wait);
worker->wqe = wqe;
io-wq: ensure we have a stable view of ->cur_work for cancellations worker->cur_work is currently protected by the lock of the wqe that the worker belongs to. When we send a signal to a worker, we need a stable view of ->cur_work, so we need to hold that lock. But this doesn't work so well, since we have the opposite order potentially on queueing work. If POLL_ADD is used with a signalfd, then io_poll_wake() is called with the signal lock, and that sometimes needs to insert work items. Add a specific worker lock that protects the current work item. Then we can guarantee that the task we're sending a signal is currently processing the exact work we think it is. Reported-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-14 00:43:34 +08:00
spin_lock_init(&worker->lock);
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
worker->task = kthread_create_on_node(io_wqe_worker, worker, wqe->node,
io-wq: add support for bounded vs unbunded work io_uring supports request types that basically have two different lifetimes: 1) Bounded completion time. These are requests like disk reads or writes, which we know will finish in a finite amount of time. 2) Unbounded completion time. These are generally networked IO, where we have no idea how long they will take to complete. Another example is POLL commands. This patch provides support for io-wq to handle these differently, so we don't starve bounded requests by tying up workers for too long. By default all work is bounded, unless otherwise specified in the work item. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08 02:41:16 +08:00
"io_wqe_worker-%d/%d", index, wqe->node);
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
if (IS_ERR(worker->task)) {
kfree(worker);
io-wq: wait for io_wq_create() to setup necessary workers We currently have a race where if setup is really slow, we can be calling io_wq_destroy() before we're done setting up. This will cause the caller to get stuck waiting for the manager to set things up, but the manager already exited. Fix this by doing a sync setup of the manager. This also fixes the case where if we failed creating workers, we'd also get stuck. In practice this race window was really small, as we already wait for the manager to start. Hence someone would have to call io_wq_destroy() after the task has started, but before it started the first loop. The reported test case forked tons of these, which is why it became an issue. Reported-by: syzbot+0f1cc17f85154f400465@syzkaller.appspotmail.com Fixes: 771b53d033e8 ("io-wq: small threadpool implementation for io_uring") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-19 23:37:07 +08:00
return false;
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
}
spin_lock_irq(&wqe->lock);
io-wq: remove now redundant struct io_wq_nulls_list Since we don't iterate these lists anymore after commit: e61df66c69b1 ("io-wq: ensure free/busy list browsing see all items") we don't need to retain the nulls value we use for them. That means it's pretty pointless to wrap the hlist_nulls_head in a structure, so get rid of it. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-14 23:00:41 +08:00
hlist_nulls_add_head_rcu(&worker->nulls_node, &wqe->free_list);
io-wq: ensure free/busy list browsing see all items We have two lists for workers in io-wq, a busy and a free list. For certain operations we want to browse all workers, and we currently do that by browsing the two separate lists. But since these lists are RCU protected, we can potentially miss workers if they move between the two lists while we're browsing them. Add a third list, all_list, that simply holds all workers. A worker is added to that list when it starts, and removed when it exits. This makes the worker iteration cleaner, too. Reported-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-14 04:54:49 +08:00
list_add_tail_rcu(&worker->all_list, &wqe->all_list);
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
worker->flags |= IO_WORKER_F_FREE;
io-wq: add support for bounded vs unbunded work io_uring supports request types that basically have two different lifetimes: 1) Bounded completion time. These are requests like disk reads or writes, which we know will finish in a finite amount of time. 2) Unbounded completion time. These are generally networked IO, where we have no idea how long they will take to complete. Another example is POLL commands. This patch provides support for io-wq to handle these differently, so we don't starve bounded requests by tying up workers for too long. By default all work is bounded, unless otherwise specified in the work item. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08 02:41:16 +08:00
if (index == IO_WQ_ACCT_BOUND)
worker->flags |= IO_WORKER_F_BOUND;
if (!acct->nr_workers && (worker->flags & IO_WORKER_F_BOUND))
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
worker->flags |= IO_WORKER_F_FIXED;
io-wq: add support for bounded vs unbunded work io_uring supports request types that basically have two different lifetimes: 1) Bounded completion time. These are requests like disk reads or writes, which we know will finish in a finite amount of time. 2) Unbounded completion time. These are generally networked IO, where we have no idea how long they will take to complete. Another example is POLL commands. This patch provides support for io-wq to handle these differently, so we don't starve bounded requests by tying up workers for too long. By default all work is bounded, unless otherwise specified in the work item. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08 02:41:16 +08:00
acct->nr_workers++;
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
spin_unlock_irq(&wqe->lock);
io-wq: add support for bounded vs unbunded work io_uring supports request types that basically have two different lifetimes: 1) Bounded completion time. These are requests like disk reads or writes, which we know will finish in a finite amount of time. 2) Unbounded completion time. These are generally networked IO, where we have no idea how long they will take to complete. Another example is POLL commands. This patch provides support for io-wq to handle these differently, so we don't starve bounded requests by tying up workers for too long. By default all work is bounded, unless otherwise specified in the work item. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08 02:41:16 +08:00
if (index == IO_WQ_ACCT_UNBOUND)
atomic_inc(&wq->user->processes);
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
wake_up_process(worker->task);
io-wq: wait for io_wq_create() to setup necessary workers We currently have a race where if setup is really slow, we can be calling io_wq_destroy() before we're done setting up. This will cause the caller to get stuck waiting for the manager to set things up, but the manager already exited. Fix this by doing a sync setup of the manager. This also fixes the case where if we failed creating workers, we'd also get stuck. In practice this race window was really small, as we already wait for the manager to start. Hence someone would have to call io_wq_destroy() after the task has started, but before it started the first loop. The reported test case forked tons of these, which is why it became an issue. Reported-by: syzbot+0f1cc17f85154f400465@syzkaller.appspotmail.com Fixes: 771b53d033e8 ("io-wq: small threadpool implementation for io_uring") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-19 23:37:07 +08:00
return true;
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
}
io-wq: add support for bounded vs unbunded work io_uring supports request types that basically have two different lifetimes: 1) Bounded completion time. These are requests like disk reads or writes, which we know will finish in a finite amount of time. 2) Unbounded completion time. These are generally networked IO, where we have no idea how long they will take to complete. Another example is POLL commands. This patch provides support for io-wq to handle these differently, so we don't starve bounded requests by tying up workers for too long. By default all work is bounded, unless otherwise specified in the work item. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08 02:41:16 +08:00
static inline bool io_wqe_need_worker(struct io_wqe *wqe, int index)
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
__must_hold(wqe->lock)
{
io-wq: add support for bounded vs unbunded work io_uring supports request types that basically have two different lifetimes: 1) Bounded completion time. These are requests like disk reads or writes, which we know will finish in a finite amount of time. 2) Unbounded completion time. These are generally networked IO, where we have no idea how long they will take to complete. Another example is POLL commands. This patch provides support for io-wq to handle these differently, so we don't starve bounded requests by tying up workers for too long. By default all work is bounded, unless otherwise specified in the work item. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08 02:41:16 +08:00
struct io_wqe_acct *acct = &wqe->acct[index];
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
io-wq: add support for bounded vs unbunded work io_uring supports request types that basically have two different lifetimes: 1) Bounded completion time. These are requests like disk reads or writes, which we know will finish in a finite amount of time. 2) Unbounded completion time. These are generally networked IO, where we have no idea how long they will take to complete. Another example is POLL commands. This patch provides support for io-wq to handle these differently, so we don't starve bounded requests by tying up workers for too long. By default all work is bounded, unless otherwise specified in the work item. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08 02:41:16 +08:00
/* if we have available workers or no work, no need */
io-wq: remove now redundant struct io_wq_nulls_list Since we don't iterate these lists anymore after commit: e61df66c69b1 ("io-wq: ensure free/busy list browsing see all items") we don't need to retain the nulls value we use for them. That means it's pretty pointless to wrap the hlist_nulls_head in a structure, so get rid of it. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-14 23:00:41 +08:00
if (!hlist_nulls_empty(&wqe->free_list) || !io_wqe_run_queue(wqe))
io-wq: add support for bounded vs unbunded work io_uring supports request types that basically have two different lifetimes: 1) Bounded completion time. These are requests like disk reads or writes, which we know will finish in a finite amount of time. 2) Unbounded completion time. These are generally networked IO, where we have no idea how long they will take to complete. Another example is POLL commands. This patch provides support for io-wq to handle these differently, so we don't starve bounded requests by tying up workers for too long. By default all work is bounded, unless otherwise specified in the work item. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08 02:41:16 +08:00
return false;
return acct->nr_workers < acct->max_workers;
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
}
/*
* Manager thread. Tasked with creating new workers, if we need them.
*/
static int io_wq_manager(void *data)
{
struct io_wq *wq = data;
io-wq: fix handling of NUMA node IDs There are several things that can go wrong in the current code on NUMA systems, especially if not all nodes are online all the time: - If the identifiers of the online nodes do not form a single contiguous block starting at zero, wq->wqes will be too small, and OOB memory accesses will occur e.g. in the loop in io_wq_create(). - If a node comes online between the call to num_online_nodes() and the for_each_node() loop in io_wq_create(), an OOB write will occur. - If a node comes online between io_wq_create() and io_wq_enqueue(), a lookup is performed for an element that doesn't exist, and an OOB read will probably occur. Fix it by: - using nr_node_ids instead of num_online_nodes() for the allocation size; nr_node_ids is calculated by setup_nr_node_ids() to be bigger than the highest node ID that could possibly come online at some point, even if those nodes' identifiers are not a contiguous block - creating workers for all possible CPUs, not just all online ones This is basically what the normal workqueue code also does, as far as I can tell. Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27 02:10:20 +08:00
int workers_to_create = num_possible_nodes();
int node;
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
io-wq: wait for io_wq_create() to setup necessary workers We currently have a race where if setup is really slow, we can be calling io_wq_destroy() before we're done setting up. This will cause the caller to get stuck waiting for the manager to set things up, but the manager already exited. Fix this by doing a sync setup of the manager. This also fixes the case where if we failed creating workers, we'd also get stuck. In practice this race window was really small, as we already wait for the manager to start. Hence someone would have to call io_wq_destroy() after the task has started, but before it started the first loop. The reported test case forked tons of these, which is why it became an issue. Reported-by: syzbot+0f1cc17f85154f400465@syzkaller.appspotmail.com Fixes: 771b53d033e8 ("io-wq: small threadpool implementation for io_uring") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-19 23:37:07 +08:00
/* create fixed workers */
io-wq: fix handling of NUMA node IDs There are several things that can go wrong in the current code on NUMA systems, especially if not all nodes are online all the time: - If the identifiers of the online nodes do not form a single contiguous block starting at zero, wq->wqes will be too small, and OOB memory accesses will occur e.g. in the loop in io_wq_create(). - If a node comes online between the call to num_online_nodes() and the for_each_node() loop in io_wq_create(), an OOB write will occur. - If a node comes online between io_wq_create() and io_wq_enqueue(), a lookup is performed for an element that doesn't exist, and an OOB read will probably occur. Fix it by: - using nr_node_ids instead of num_online_nodes() for the allocation size; nr_node_ids is calculated by setup_nr_node_ids() to be bigger than the highest node ID that could possibly come online at some point, even if those nodes' identifiers are not a contiguous block - creating workers for all possible CPUs, not just all online ones This is basically what the normal workqueue code also does, as far as I can tell. Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27 02:10:20 +08:00
refcount_set(&wq->refs, workers_to_create);
for_each_node(node) {
if (!create_io_worker(wq, wq->wqes[node], IO_WQ_ACCT_BOUND))
goto err;
workers_to_create--;
io-wq: wait for io_wq_create() to setup necessary workers We currently have a race where if setup is really slow, we can be calling io_wq_destroy() before we're done setting up. This will cause the caller to get stuck waiting for the manager to set things up, but the manager already exited. Fix this by doing a sync setup of the manager. This also fixes the case where if we failed creating workers, we'd also get stuck. In practice this race window was really small, as we already wait for the manager to start. Hence someone would have to call io_wq_destroy() after the task has started, but before it started the first loop. The reported test case forked tons of these, which is why it became an issue. Reported-by: syzbot+0f1cc17f85154f400465@syzkaller.appspotmail.com Fixes: 771b53d033e8 ("io-wq: small threadpool implementation for io_uring") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-19 23:37:07 +08:00
}
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
io-wq: wait for io_wq_create() to setup necessary workers We currently have a race where if setup is really slow, we can be calling io_wq_destroy() before we're done setting up. This will cause the caller to get stuck waiting for the manager to set things up, but the manager already exited. Fix this by doing a sync setup of the manager. This also fixes the case where if we failed creating workers, we'd also get stuck. In practice this race window was really small, as we already wait for the manager to start. Hence someone would have to call io_wq_destroy() after the task has started, but before it started the first loop. The reported test case forked tons of these, which is why it became an issue. Reported-by: syzbot+0f1cc17f85154f400465@syzkaller.appspotmail.com Fixes: 771b53d033e8 ("io-wq: small threadpool implementation for io_uring") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-19 23:37:07 +08:00
complete(&wq->done);
while (!kthread_should_stop()) {
io-wq: fix handling of NUMA node IDs There are several things that can go wrong in the current code on NUMA systems, especially if not all nodes are online all the time: - If the identifiers of the online nodes do not form a single contiguous block starting at zero, wq->wqes will be too small, and OOB memory accesses will occur e.g. in the loop in io_wq_create(). - If a node comes online between the call to num_online_nodes() and the for_each_node() loop in io_wq_create(), an OOB write will occur. - If a node comes online between io_wq_create() and io_wq_enqueue(), a lookup is performed for an element that doesn't exist, and an OOB read will probably occur. Fix it by: - using nr_node_ids instead of num_online_nodes() for the allocation size; nr_node_ids is calculated by setup_nr_node_ids() to be bigger than the highest node ID that could possibly come online at some point, even if those nodes' identifiers are not a contiguous block - creating workers for all possible CPUs, not just all online ones This is basically what the normal workqueue code also does, as far as I can tell. Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27 02:10:20 +08:00
for_each_node(node) {
struct io_wqe *wqe = wq->wqes[node];
io-wq: add support for bounded vs unbunded work io_uring supports request types that basically have two different lifetimes: 1) Bounded completion time. These are requests like disk reads or writes, which we know will finish in a finite amount of time. 2) Unbounded completion time. These are generally networked IO, where we have no idea how long they will take to complete. Another example is POLL commands. This patch provides support for io-wq to handle these differently, so we don't starve bounded requests by tying up workers for too long. By default all work is bounded, unless otherwise specified in the work item. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08 02:41:16 +08:00
bool fork_worker[2] = { false, false };
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
spin_lock_irq(&wqe->lock);
io-wq: add support for bounded vs unbunded work io_uring supports request types that basically have two different lifetimes: 1) Bounded completion time. These are requests like disk reads or writes, which we know will finish in a finite amount of time. 2) Unbounded completion time. These are generally networked IO, where we have no idea how long they will take to complete. Another example is POLL commands. This patch provides support for io-wq to handle these differently, so we don't starve bounded requests by tying up workers for too long. By default all work is bounded, unless otherwise specified in the work item. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08 02:41:16 +08:00
if (io_wqe_need_worker(wqe, IO_WQ_ACCT_BOUND))
fork_worker[IO_WQ_ACCT_BOUND] = true;
if (io_wqe_need_worker(wqe, IO_WQ_ACCT_UNBOUND))
fork_worker[IO_WQ_ACCT_UNBOUND] = true;
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
spin_unlock_irq(&wqe->lock);
io-wq: add support for bounded vs unbunded work io_uring supports request types that basically have two different lifetimes: 1) Bounded completion time. These are requests like disk reads or writes, which we know will finish in a finite amount of time. 2) Unbounded completion time. These are generally networked IO, where we have no idea how long they will take to complete. Another example is POLL commands. This patch provides support for io-wq to handle these differently, so we don't starve bounded requests by tying up workers for too long. By default all work is bounded, unless otherwise specified in the work item. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08 02:41:16 +08:00
if (fork_worker[IO_WQ_ACCT_BOUND])
create_io_worker(wq, wqe, IO_WQ_ACCT_BOUND);
if (fork_worker[IO_WQ_ACCT_UNBOUND])
create_io_worker(wq, wqe, IO_WQ_ACCT_UNBOUND);
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
}
set_current_state(TASK_INTERRUPTIBLE);
schedule_timeout(HZ);
}
return 0;
io-wq: wait for io_wq_create() to setup necessary workers We currently have a race where if setup is really slow, we can be calling io_wq_destroy() before we're done setting up. This will cause the caller to get stuck waiting for the manager to set things up, but the manager already exited. Fix this by doing a sync setup of the manager. This also fixes the case where if we failed creating workers, we'd also get stuck. In practice this race window was really small, as we already wait for the manager to start. Hence someone would have to call io_wq_destroy() after the task has started, but before it started the first loop. The reported test case forked tons of these, which is why it became an issue. Reported-by: syzbot+0f1cc17f85154f400465@syzkaller.appspotmail.com Fixes: 771b53d033e8 ("io-wq: small threadpool implementation for io_uring") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-19 23:37:07 +08:00
err:
set_bit(IO_WQ_BIT_ERROR, &wq->state);
set_bit(IO_WQ_BIT_EXIT, &wq->state);
io-wq: fix handling of NUMA node IDs There are several things that can go wrong in the current code on NUMA systems, especially if not all nodes are online all the time: - If the identifiers of the online nodes do not form a single contiguous block starting at zero, wq->wqes will be too small, and OOB memory accesses will occur e.g. in the loop in io_wq_create(). - If a node comes online between the call to num_online_nodes() and the for_each_node() loop in io_wq_create(), an OOB write will occur. - If a node comes online between io_wq_create() and io_wq_enqueue(), a lookup is performed for an element that doesn't exist, and an OOB read will probably occur. Fix it by: - using nr_node_ids instead of num_online_nodes() for the allocation size; nr_node_ids is calculated by setup_nr_node_ids() to be bigger than the highest node ID that could possibly come online at some point, even if those nodes' identifiers are not a contiguous block - creating workers for all possible CPUs, not just all online ones This is basically what the normal workqueue code also does, as far as I can tell. Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27 02:10:20 +08:00
if (refcount_sub_and_test(workers_to_create, &wq->refs))
io-wq: wait for io_wq_create() to setup necessary workers We currently have a race where if setup is really slow, we can be calling io_wq_destroy() before we're done setting up. This will cause the caller to get stuck waiting for the manager to set things up, but the manager already exited. Fix this by doing a sync setup of the manager. This also fixes the case where if we failed creating workers, we'd also get stuck. In practice this race window was really small, as we already wait for the manager to start. Hence someone would have to call io_wq_destroy() after the task has started, but before it started the first loop. The reported test case forked tons of these, which is why it became an issue. Reported-by: syzbot+0f1cc17f85154f400465@syzkaller.appspotmail.com Fixes: 771b53d033e8 ("io-wq: small threadpool implementation for io_uring") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-19 23:37:07 +08:00
complete(&wq->done);
return 0;
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
}
io-wq: add support for bounded vs unbunded work io_uring supports request types that basically have two different lifetimes: 1) Bounded completion time. These are requests like disk reads or writes, which we know will finish in a finite amount of time. 2) Unbounded completion time. These are generally networked IO, where we have no idea how long they will take to complete. Another example is POLL commands. This patch provides support for io-wq to handle these differently, so we don't starve bounded requests by tying up workers for too long. By default all work is bounded, unless otherwise specified in the work item. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08 02:41:16 +08:00
static bool io_wq_can_queue(struct io_wqe *wqe, struct io_wqe_acct *acct,
struct io_wq_work *work)
{
bool free_worker;
if (!(work->flags & IO_WQ_WORK_UNBOUND))
return true;
if (atomic_read(&acct->nr_running))
return true;
rcu_read_lock();
io-wq: remove now redundant struct io_wq_nulls_list Since we don't iterate these lists anymore after commit: e61df66c69b1 ("io-wq: ensure free/busy list browsing see all items") we don't need to retain the nulls value we use for them. That means it's pretty pointless to wrap the hlist_nulls_head in a structure, so get rid of it. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-14 23:00:41 +08:00
free_worker = !hlist_nulls_empty(&wqe->free_list);
io-wq: add support for bounded vs unbunded work io_uring supports request types that basically have two different lifetimes: 1) Bounded completion time. These are requests like disk reads or writes, which we know will finish in a finite amount of time. 2) Unbounded completion time. These are generally networked IO, where we have no idea how long they will take to complete. Another example is POLL commands. This patch provides support for io-wq to handle these differently, so we don't starve bounded requests by tying up workers for too long. By default all work is bounded, unless otherwise specified in the work item. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08 02:41:16 +08:00
rcu_read_unlock();
if (free_worker)
return true;
if (atomic_read(&wqe->wq->user->processes) >= acct->max_workers &&
!(capable(CAP_SYS_RESOURCE) || capable(CAP_SYS_ADMIN)))
return false;
return true;
}
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
static void io_wqe_enqueue(struct io_wqe *wqe, struct io_wq_work *work)
{
io-wq: add support for bounded vs unbunded work io_uring supports request types that basically have two different lifetimes: 1) Bounded completion time. These are requests like disk reads or writes, which we know will finish in a finite amount of time. 2) Unbounded completion time. These are generally networked IO, where we have no idea how long they will take to complete. Another example is POLL commands. This patch provides support for io-wq to handle these differently, so we don't starve bounded requests by tying up workers for too long. By default all work is bounded, unless otherwise specified in the work item. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08 02:41:16 +08:00
struct io_wqe_acct *acct = io_work_get_acct(wqe, work);
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
unsigned long flags;
io-wq: add support for bounded vs unbunded work io_uring supports request types that basically have two different lifetimes: 1) Bounded completion time. These are requests like disk reads or writes, which we know will finish in a finite amount of time. 2) Unbounded completion time. These are generally networked IO, where we have no idea how long they will take to complete. Another example is POLL commands. This patch provides support for io-wq to handle these differently, so we don't starve bounded requests by tying up workers for too long. By default all work is bounded, unless otherwise specified in the work item. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08 02:41:16 +08:00
/*
* Do early check to see if we need a new unbound worker, and if we do,
* if we're allowed to do so. This isn't 100% accurate as there's a
* gap between this check and incrementing the value, but that's OK.
* It's close enough to not be an issue, fork() has the same delay.
*/
if (unlikely(!io_wq_can_queue(wqe, acct, work))) {
work->flags |= IO_WQ_WORK_CANCEL;
work->func(&work);
return;
}
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
spin_lock_irqsave(&wqe->lock, flags);
io-wq: shrink io_wq_work a bit Currently we're using 40 bytes for the io_wq_work structure, and 16 of those is the doubly link list node. We don't need doubly linked lists, we always add to tail to keep things ordered, and any other use case is list traversal with deletion. For the deletion case, we can easily support any node deletion by keeping track of the previous entry. This shrinks io_wq_work to 32 bytes, and subsequently io_kiock from io_uring to 216 to 208 bytes. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27 02:59:32 +08:00
wq_list_add_tail(&work->list, &wqe->work_list);
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
wqe->flags &= ~IO_WQE_FLAG_STALLED;
spin_unlock_irqrestore(&wqe->lock, flags);
io-wq: add support for bounded vs unbunded work io_uring supports request types that basically have two different lifetimes: 1) Bounded completion time. These are requests like disk reads or writes, which we know will finish in a finite amount of time. 2) Unbounded completion time. These are generally networked IO, where we have no idea how long they will take to complete. Another example is POLL commands. This patch provides support for io-wq to handle these differently, so we don't starve bounded requests by tying up workers for too long. By default all work is bounded, unless otherwise specified in the work item. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08 02:41:16 +08:00
if (!atomic_read(&acct->nr_running))
io_wqe_wake_worker(wqe, acct);
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
}
void io_wq_enqueue(struct io_wq *wq, struct io_wq_work *work)
{
struct io_wqe *wqe = wq->wqes[numa_node_id()];
io_wqe_enqueue(wqe, work);
}
/*
* Enqueue work, hashed by some key. Work items that hash to the same value
* will not be done in parallel. Used to limit concurrent writes, generally
* hashed by inode.
*/
void io_wq_enqueue_hashed(struct io_wq *wq, struct io_wq_work *work, void *val)
{
struct io_wqe *wqe = wq->wqes[numa_node_id()];
unsigned bit;
bit = hash_ptr(val, IO_WQ_HASH_ORDER);
work->flags |= (IO_WQ_WORK_HASHED | (bit << IO_WQ_HASH_SHIFT));
io_wqe_enqueue(wqe, work);
}
static bool io_wqe_worker_send_sig(struct io_worker *worker, void *data)
{
send_sig(SIGINT, worker->task, 1);
return false;
}
/*
* Iterate the passed in list and call the specific function for each
* worker that isn't exiting
*/
static bool io_wq_for_each_worker(struct io_wqe *wqe,
bool (*func)(struct io_worker *, void *),
void *data)
{
struct io_worker *worker;
bool ret = false;
io-wq: ensure free/busy list browsing see all items We have two lists for workers in io-wq, a busy and a free list. For certain operations we want to browse all workers, and we currently do that by browsing the two separate lists. But since these lists are RCU protected, we can potentially miss workers if they move between the two lists while we're browsing them. Add a third list, all_list, that simply holds all workers. A worker is added to that list when it starts, and removed when it exits. This makes the worker iteration cleaner, too. Reported-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-14 04:54:49 +08:00
list_for_each_entry_rcu(worker, &wqe->all_list, all_list) {
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
if (io_worker_get(worker)) {
ret = func(worker, data);
io_worker_release(worker);
if (ret)
break;
}
}
io-wq: ensure free/busy list browsing see all items We have two lists for workers in io-wq, a busy and a free list. For certain operations we want to browse all workers, and we currently do that by browsing the two separate lists. But since these lists are RCU protected, we can potentially miss workers if they move between the two lists while we're browsing them. Add a third list, all_list, that simply holds all workers. A worker is added to that list when it starts, and removed when it exits. This makes the worker iteration cleaner, too. Reported-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-14 04:54:49 +08:00
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
return ret;
}
void io_wq_cancel_all(struct io_wq *wq)
{
io-wq: fix handling of NUMA node IDs There are several things that can go wrong in the current code on NUMA systems, especially if not all nodes are online all the time: - If the identifiers of the online nodes do not form a single contiguous block starting at zero, wq->wqes will be too small, and OOB memory accesses will occur e.g. in the loop in io_wq_create(). - If a node comes online between the call to num_online_nodes() and the for_each_node() loop in io_wq_create(), an OOB write will occur. - If a node comes online between io_wq_create() and io_wq_enqueue(), a lookup is performed for an element that doesn't exist, and an OOB read will probably occur. Fix it by: - using nr_node_ids instead of num_online_nodes() for the allocation size; nr_node_ids is calculated by setup_nr_node_ids() to be bigger than the highest node ID that could possibly come online at some point, even if those nodes' identifiers are not a contiguous block - creating workers for all possible CPUs, not just all online ones This is basically what the normal workqueue code also does, as far as I can tell. Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27 02:10:20 +08:00
int node;
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
set_bit(IO_WQ_BIT_CANCEL, &wq->state);
/*
* Browse both lists, as there's a gap between handing work off
* to a worker and the worker putting itself on the busy_list
*/
rcu_read_lock();
io-wq: fix handling of NUMA node IDs There are several things that can go wrong in the current code on NUMA systems, especially if not all nodes are online all the time: - If the identifiers of the online nodes do not form a single contiguous block starting at zero, wq->wqes will be too small, and OOB memory accesses will occur e.g. in the loop in io_wq_create(). - If a node comes online between the call to num_online_nodes() and the for_each_node() loop in io_wq_create(), an OOB write will occur. - If a node comes online between io_wq_create() and io_wq_enqueue(), a lookup is performed for an element that doesn't exist, and an OOB read will probably occur. Fix it by: - using nr_node_ids instead of num_online_nodes() for the allocation size; nr_node_ids is calculated by setup_nr_node_ids() to be bigger than the highest node ID that could possibly come online at some point, even if those nodes' identifiers are not a contiguous block - creating workers for all possible CPUs, not just all online ones This is basically what the normal workqueue code also does, as far as I can tell. Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27 02:10:20 +08:00
for_each_node(node) {
struct io_wqe *wqe = wq->wqes[node];
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
io-wq: ensure free/busy list browsing see all items We have two lists for workers in io-wq, a busy and a free list. For certain operations we want to browse all workers, and we currently do that by browsing the two separate lists. But since these lists are RCU protected, we can potentially miss workers if they move between the two lists while we're browsing them. Add a third list, all_list, that simply holds all workers. A worker is added to that list when it starts, and removed when it exits. This makes the worker iteration cleaner, too. Reported-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-14 04:54:49 +08:00
io_wq_for_each_worker(wqe, io_wqe_worker_send_sig, NULL);
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
}
rcu_read_unlock();
}
io_uring: support for generic async request cancel This adds support for IORING_OP_ASYNC_CANCEL, which will attempt to cancel requests that have been punted to async context and are now in-flight. This works for regular read/write requests to files, as long as they haven't been started yet. For socket based IO (or things like accept4(2)), we can cancel work that is already running as well. To cancel a request, the sqe must have ->addr set to the user_data of the request it wishes to cancel. If the request is cancelled successfully, the original request is completed with -ECANCELED and the cancel request is completed with a result of 0. If the request was already running, the original may or may not complete in error. The cancel request will complete with -EALREADY for that case. And finally, if the request to cancel wasn't found, the cancel request is completed with -ENOENT. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-29 11:49:21 +08:00
struct io_cb_cancel_data {
struct io_wqe *wqe;
work_cancel_fn *cancel;
void *caller_data;
};
static bool io_work_cancel(struct io_worker *worker, void *cancel_data)
{
struct io_cb_cancel_data *data = cancel_data;
io-wq: use proper nesting IRQ disabling spinlocks for cancel We don't know what context we'll be called in for cancel, it could very well be with IRQs disabled already. Use the IRQ saving variants of the locking primitives. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-06 04:51:51 +08:00
unsigned long flags;
io_uring: support for generic async request cancel This adds support for IORING_OP_ASYNC_CANCEL, which will attempt to cancel requests that have been punted to async context and are now in-flight. This works for regular read/write requests to files, as long as they haven't been started yet. For socket based IO (or things like accept4(2)), we can cancel work that is already running as well. To cancel a request, the sqe must have ->addr set to the user_data of the request it wishes to cancel. If the request is cancelled successfully, the original request is completed with -ECANCELED and the cancel request is completed with a result of 0. If the request was already running, the original may or may not complete in error. The cancel request will complete with -EALREADY for that case. And finally, if the request to cancel wasn't found, the cancel request is completed with -ENOENT. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-29 11:49:21 +08:00
bool ret = false;
/*
* Hold the lock to avoid ->cur_work going out of scope, caller
io-wq: ensure we have a stable view of ->cur_work for cancellations worker->cur_work is currently protected by the lock of the wqe that the worker belongs to. When we send a signal to a worker, we need a stable view of ->cur_work, so we need to hold that lock. But this doesn't work so well, since we have the opposite order potentially on queueing work. If POLL_ADD is used with a signalfd, then io_poll_wake() is called with the signal lock, and that sometimes needs to insert work items. Add a specific worker lock that protects the current work item. Then we can guarantee that the task we're sending a signal is currently processing the exact work we think it is. Reported-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-14 00:43:34 +08:00
* may dereference the passed in work.
io_uring: support for generic async request cancel This adds support for IORING_OP_ASYNC_CANCEL, which will attempt to cancel requests that have been punted to async context and are now in-flight. This works for regular read/write requests to files, as long as they haven't been started yet. For socket based IO (or things like accept4(2)), we can cancel work that is already running as well. To cancel a request, the sqe must have ->addr set to the user_data of the request it wishes to cancel. If the request is cancelled successfully, the original request is completed with -ECANCELED and the cancel request is completed with a result of 0. If the request was already running, the original may or may not complete in error. The cancel request will complete with -EALREADY for that case. And finally, if the request to cancel wasn't found, the cancel request is completed with -ENOENT. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-29 11:49:21 +08:00
*/
io-wq: ensure we have a stable view of ->cur_work for cancellations worker->cur_work is currently protected by the lock of the wqe that the worker belongs to. When we send a signal to a worker, we need a stable view of ->cur_work, so we need to hold that lock. But this doesn't work so well, since we have the opposite order potentially on queueing work. If POLL_ADD is used with a signalfd, then io_poll_wake() is called with the signal lock, and that sometimes needs to insert work items. Add a specific worker lock that protects the current work item. Then we can guarantee that the task we're sending a signal is currently processing the exact work we think it is. Reported-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-14 00:43:34 +08:00
spin_lock_irqsave(&worker->lock, flags);
io_uring: support for generic async request cancel This adds support for IORING_OP_ASYNC_CANCEL, which will attempt to cancel requests that have been punted to async context and are now in-flight. This works for regular read/write requests to files, as long as they haven't been started yet. For socket based IO (or things like accept4(2)), we can cancel work that is already running as well. To cancel a request, the sqe must have ->addr set to the user_data of the request it wishes to cancel. If the request is cancelled successfully, the original request is completed with -ECANCELED and the cancel request is completed with a result of 0. If the request was already running, the original may or may not complete in error. The cancel request will complete with -EALREADY for that case. And finally, if the request to cancel wasn't found, the cancel request is completed with -ENOENT. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-29 11:49:21 +08:00
if (worker->cur_work &&
data->cancel(worker->cur_work, data->caller_data)) {
send_sig(SIGINT, worker->task, 1);
ret = true;
}
io-wq: ensure we have a stable view of ->cur_work for cancellations worker->cur_work is currently protected by the lock of the wqe that the worker belongs to. When we send a signal to a worker, we need a stable view of ->cur_work, so we need to hold that lock. But this doesn't work so well, since we have the opposite order potentially on queueing work. If POLL_ADD is used with a signalfd, then io_poll_wake() is called with the signal lock, and that sometimes needs to insert work items. Add a specific worker lock that protects the current work item. Then we can guarantee that the task we're sending a signal is currently processing the exact work we think it is. Reported-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-14 00:43:34 +08:00
spin_unlock_irqrestore(&worker->lock, flags);
io_uring: support for generic async request cancel This adds support for IORING_OP_ASYNC_CANCEL, which will attempt to cancel requests that have been punted to async context and are now in-flight. This works for regular read/write requests to files, as long as they haven't been started yet. For socket based IO (or things like accept4(2)), we can cancel work that is already running as well. To cancel a request, the sqe must have ->addr set to the user_data of the request it wishes to cancel. If the request is cancelled successfully, the original request is completed with -ECANCELED and the cancel request is completed with a result of 0. If the request was already running, the original may or may not complete in error. The cancel request will complete with -EALREADY for that case. And finally, if the request to cancel wasn't found, the cancel request is completed with -ENOENT. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-29 11:49:21 +08:00
return ret;
}
static enum io_wq_cancel io_wqe_cancel_cb_work(struct io_wqe *wqe,
work_cancel_fn *cancel,
void *cancel_data)
{
struct io_cb_cancel_data data = {
.wqe = wqe,
.cancel = cancel,
.caller_data = cancel_data,
};
io-wq: shrink io_wq_work a bit Currently we're using 40 bytes for the io_wq_work structure, and 16 of those is the doubly link list node. We don't need doubly linked lists, we always add to tail to keep things ordered, and any other use case is list traversal with deletion. For the deletion case, we can easily support any node deletion by keeping track of the previous entry. This shrinks io_wq_work to 32 bytes, and subsequently io_kiock from io_uring to 216 to 208 bytes. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27 02:59:32 +08:00
struct io_wq_work_node *node, *prev;
io_uring: support for generic async request cancel This adds support for IORING_OP_ASYNC_CANCEL, which will attempt to cancel requests that have been punted to async context and are now in-flight. This works for regular read/write requests to files, as long as they haven't been started yet. For socket based IO (or things like accept4(2)), we can cancel work that is already running as well. To cancel a request, the sqe must have ->addr set to the user_data of the request it wishes to cancel. If the request is cancelled successfully, the original request is completed with -ECANCELED and the cancel request is completed with a result of 0. If the request was already running, the original may or may not complete in error. The cancel request will complete with -EALREADY for that case. And finally, if the request to cancel wasn't found, the cancel request is completed with -ENOENT. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-29 11:49:21 +08:00
struct io_wq_work *work;
io-wq: use proper nesting IRQ disabling spinlocks for cancel We don't know what context we'll be called in for cancel, it could very well be with IRQs disabled already. Use the IRQ saving variants of the locking primitives. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-06 04:51:51 +08:00
unsigned long flags;
io_uring: support for generic async request cancel This adds support for IORING_OP_ASYNC_CANCEL, which will attempt to cancel requests that have been punted to async context and are now in-flight. This works for regular read/write requests to files, as long as they haven't been started yet. For socket based IO (or things like accept4(2)), we can cancel work that is already running as well. To cancel a request, the sqe must have ->addr set to the user_data of the request it wishes to cancel. If the request is cancelled successfully, the original request is completed with -ECANCELED and the cancel request is completed with a result of 0. If the request was already running, the original may or may not complete in error. The cancel request will complete with -EALREADY for that case. And finally, if the request to cancel wasn't found, the cancel request is completed with -ENOENT. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-29 11:49:21 +08:00
bool found = false;
io-wq: use proper nesting IRQ disabling spinlocks for cancel We don't know what context we'll be called in for cancel, it could very well be with IRQs disabled already. Use the IRQ saving variants of the locking primitives. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-06 04:51:51 +08:00
spin_lock_irqsave(&wqe->lock, flags);
io-wq: shrink io_wq_work a bit Currently we're using 40 bytes for the io_wq_work structure, and 16 of those is the doubly link list node. We don't need doubly linked lists, we always add to tail to keep things ordered, and any other use case is list traversal with deletion. For the deletion case, we can easily support any node deletion by keeping track of the previous entry. This shrinks io_wq_work to 32 bytes, and subsequently io_kiock from io_uring to 216 to 208 bytes. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27 02:59:32 +08:00
wq_list_for_each(node, prev, &wqe->work_list) {
work = container_of(node, struct io_wq_work, list);
io_uring: support for generic async request cancel This adds support for IORING_OP_ASYNC_CANCEL, which will attempt to cancel requests that have been punted to async context and are now in-flight. This works for regular read/write requests to files, as long as they haven't been started yet. For socket based IO (or things like accept4(2)), we can cancel work that is already running as well. To cancel a request, the sqe must have ->addr set to the user_data of the request it wishes to cancel. If the request is cancelled successfully, the original request is completed with -ECANCELED and the cancel request is completed with a result of 0. If the request was already running, the original may or may not complete in error. The cancel request will complete with -EALREADY for that case. And finally, if the request to cancel wasn't found, the cancel request is completed with -ENOENT. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-29 11:49:21 +08:00
if (cancel(work, cancel_data)) {
io-wq: shrink io_wq_work a bit Currently we're using 40 bytes for the io_wq_work structure, and 16 of those is the doubly link list node. We don't need doubly linked lists, we always add to tail to keep things ordered, and any other use case is list traversal with deletion. For the deletion case, we can easily support any node deletion by keeping track of the previous entry. This shrinks io_wq_work to 32 bytes, and subsequently io_kiock from io_uring to 216 to 208 bytes. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27 02:59:32 +08:00
wq_node_del(&wqe->work_list, node, prev);
io_uring: support for generic async request cancel This adds support for IORING_OP_ASYNC_CANCEL, which will attempt to cancel requests that have been punted to async context and are now in-flight. This works for regular read/write requests to files, as long as they haven't been started yet. For socket based IO (or things like accept4(2)), we can cancel work that is already running as well. To cancel a request, the sqe must have ->addr set to the user_data of the request it wishes to cancel. If the request is cancelled successfully, the original request is completed with -ECANCELED and the cancel request is completed with a result of 0. If the request was already running, the original may or may not complete in error. The cancel request will complete with -EALREADY for that case. And finally, if the request to cancel wasn't found, the cancel request is completed with -ENOENT. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-29 11:49:21 +08:00
found = true;
break;
}
}
io-wq: use proper nesting IRQ disabling spinlocks for cancel We don't know what context we'll be called in for cancel, it could very well be with IRQs disabled already. Use the IRQ saving variants of the locking primitives. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-06 04:51:51 +08:00
spin_unlock_irqrestore(&wqe->lock, flags);
io_uring: support for generic async request cancel This adds support for IORING_OP_ASYNC_CANCEL, which will attempt to cancel requests that have been punted to async context and are now in-flight. This works for regular read/write requests to files, as long as they haven't been started yet. For socket based IO (or things like accept4(2)), we can cancel work that is already running as well. To cancel a request, the sqe must have ->addr set to the user_data of the request it wishes to cancel. If the request is cancelled successfully, the original request is completed with -ECANCELED and the cancel request is completed with a result of 0. If the request was already running, the original may or may not complete in error. The cancel request will complete with -EALREADY for that case. And finally, if the request to cancel wasn't found, the cancel request is completed with -ENOENT. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-29 11:49:21 +08:00
if (found) {
work->flags |= IO_WQ_WORK_CANCEL;
work->func(&work);
return IO_WQ_CANCEL_OK;
}
rcu_read_lock();
io-wq: ensure free/busy list browsing see all items We have two lists for workers in io-wq, a busy and a free list. For certain operations we want to browse all workers, and we currently do that by browsing the two separate lists. But since these lists are RCU protected, we can potentially miss workers if they move between the two lists while we're browsing them. Add a third list, all_list, that simply holds all workers. A worker is added to that list when it starts, and removed when it exits. This makes the worker iteration cleaner, too. Reported-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-14 04:54:49 +08:00
found = io_wq_for_each_worker(wqe, io_work_cancel, &data);
io_uring: support for generic async request cancel This adds support for IORING_OP_ASYNC_CANCEL, which will attempt to cancel requests that have been punted to async context and are now in-flight. This works for regular read/write requests to files, as long as they haven't been started yet. For socket based IO (or things like accept4(2)), we can cancel work that is already running as well. To cancel a request, the sqe must have ->addr set to the user_data of the request it wishes to cancel. If the request is cancelled successfully, the original request is completed with -ECANCELED and the cancel request is completed with a result of 0. If the request was already running, the original may or may not complete in error. The cancel request will complete with -EALREADY for that case. And finally, if the request to cancel wasn't found, the cancel request is completed with -ENOENT. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-29 11:49:21 +08:00
rcu_read_unlock();
return found ? IO_WQ_CANCEL_RUNNING : IO_WQ_CANCEL_NOTFOUND;
}
enum io_wq_cancel io_wq_cancel_cb(struct io_wq *wq, work_cancel_fn *cancel,
void *data)
{
enum io_wq_cancel ret = IO_WQ_CANCEL_NOTFOUND;
io-wq: fix handling of NUMA node IDs There are several things that can go wrong in the current code on NUMA systems, especially if not all nodes are online all the time: - If the identifiers of the online nodes do not form a single contiguous block starting at zero, wq->wqes will be too small, and OOB memory accesses will occur e.g. in the loop in io_wq_create(). - If a node comes online between the call to num_online_nodes() and the for_each_node() loop in io_wq_create(), an OOB write will occur. - If a node comes online between io_wq_create() and io_wq_enqueue(), a lookup is performed for an element that doesn't exist, and an OOB read will probably occur. Fix it by: - using nr_node_ids instead of num_online_nodes() for the allocation size; nr_node_ids is calculated by setup_nr_node_ids() to be bigger than the highest node ID that could possibly come online at some point, even if those nodes' identifiers are not a contiguous block - creating workers for all possible CPUs, not just all online ones This is basically what the normal workqueue code also does, as far as I can tell. Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27 02:10:20 +08:00
int node;
io_uring: support for generic async request cancel This adds support for IORING_OP_ASYNC_CANCEL, which will attempt to cancel requests that have been punted to async context and are now in-flight. This works for regular read/write requests to files, as long as they haven't been started yet. For socket based IO (or things like accept4(2)), we can cancel work that is already running as well. To cancel a request, the sqe must have ->addr set to the user_data of the request it wishes to cancel. If the request is cancelled successfully, the original request is completed with -ECANCELED and the cancel request is completed with a result of 0. If the request was already running, the original may or may not complete in error. The cancel request will complete with -EALREADY for that case. And finally, if the request to cancel wasn't found, the cancel request is completed with -ENOENT. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-29 11:49:21 +08:00
io-wq: fix handling of NUMA node IDs There are several things that can go wrong in the current code on NUMA systems, especially if not all nodes are online all the time: - If the identifiers of the online nodes do not form a single contiguous block starting at zero, wq->wqes will be too small, and OOB memory accesses will occur e.g. in the loop in io_wq_create(). - If a node comes online between the call to num_online_nodes() and the for_each_node() loop in io_wq_create(), an OOB write will occur. - If a node comes online between io_wq_create() and io_wq_enqueue(), a lookup is performed for an element that doesn't exist, and an OOB read will probably occur. Fix it by: - using nr_node_ids instead of num_online_nodes() for the allocation size; nr_node_ids is calculated by setup_nr_node_ids() to be bigger than the highest node ID that could possibly come online at some point, even if those nodes' identifiers are not a contiguous block - creating workers for all possible CPUs, not just all online ones This is basically what the normal workqueue code also does, as far as I can tell. Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27 02:10:20 +08:00
for_each_node(node) {
struct io_wqe *wqe = wq->wqes[node];
io_uring: support for generic async request cancel This adds support for IORING_OP_ASYNC_CANCEL, which will attempt to cancel requests that have been punted to async context and are now in-flight. This works for regular read/write requests to files, as long as they haven't been started yet. For socket based IO (or things like accept4(2)), we can cancel work that is already running as well. To cancel a request, the sqe must have ->addr set to the user_data of the request it wishes to cancel. If the request is cancelled successfully, the original request is completed with -ECANCELED and the cancel request is completed with a result of 0. If the request was already running, the original may or may not complete in error. The cancel request will complete with -EALREADY for that case. And finally, if the request to cancel wasn't found, the cancel request is completed with -ENOENT. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-29 11:49:21 +08:00
ret = io_wqe_cancel_cb_work(wqe, cancel, data);
if (ret != IO_WQ_CANCEL_NOTFOUND)
break;
}
return ret;
}
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
static bool io_wq_worker_cancel(struct io_worker *worker, void *data)
{
struct io_wq_work *work = data;
io-wq: ensure we have a stable view of ->cur_work for cancellations worker->cur_work is currently protected by the lock of the wqe that the worker belongs to. When we send a signal to a worker, we need a stable view of ->cur_work, so we need to hold that lock. But this doesn't work so well, since we have the opposite order potentially on queueing work. If POLL_ADD is used with a signalfd, then io_poll_wake() is called with the signal lock, and that sometimes needs to insert work items. Add a specific worker lock that protects the current work item. Then we can guarantee that the task we're sending a signal is currently processing the exact work we think it is. Reported-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-14 00:43:34 +08:00
unsigned long flags;
bool ret = false;
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
io-wq: ensure we have a stable view of ->cur_work for cancellations worker->cur_work is currently protected by the lock of the wqe that the worker belongs to. When we send a signal to a worker, we need a stable view of ->cur_work, so we need to hold that lock. But this doesn't work so well, since we have the opposite order potentially on queueing work. If POLL_ADD is used with a signalfd, then io_poll_wake() is called with the signal lock, and that sometimes needs to insert work items. Add a specific worker lock that protects the current work item. Then we can guarantee that the task we're sending a signal is currently processing the exact work we think it is. Reported-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-14 00:43:34 +08:00
if (worker->cur_work != work)
return false;
spin_lock_irqsave(&worker->lock, flags);
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
if (worker->cur_work == work) {
send_sig(SIGINT, worker->task, 1);
io-wq: ensure we have a stable view of ->cur_work for cancellations worker->cur_work is currently protected by the lock of the wqe that the worker belongs to. When we send a signal to a worker, we need a stable view of ->cur_work, so we need to hold that lock. But this doesn't work so well, since we have the opposite order potentially on queueing work. If POLL_ADD is used with a signalfd, then io_poll_wake() is called with the signal lock, and that sometimes needs to insert work items. Add a specific worker lock that protects the current work item. Then we can guarantee that the task we're sending a signal is currently processing the exact work we think it is. Reported-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-14 00:43:34 +08:00
ret = true;
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
}
io-wq: ensure we have a stable view of ->cur_work for cancellations worker->cur_work is currently protected by the lock of the wqe that the worker belongs to. When we send a signal to a worker, we need a stable view of ->cur_work, so we need to hold that lock. But this doesn't work so well, since we have the opposite order potentially on queueing work. If POLL_ADD is used with a signalfd, then io_poll_wake() is called with the signal lock, and that sometimes needs to insert work items. Add a specific worker lock that protects the current work item. Then we can guarantee that the task we're sending a signal is currently processing the exact work we think it is. Reported-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-14 00:43:34 +08:00
spin_unlock_irqrestore(&worker->lock, flags);
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
io-wq: ensure we have a stable view of ->cur_work for cancellations worker->cur_work is currently protected by the lock of the wqe that the worker belongs to. When we send a signal to a worker, we need a stable view of ->cur_work, so we need to hold that lock. But this doesn't work so well, since we have the opposite order potentially on queueing work. If POLL_ADD is used with a signalfd, then io_poll_wake() is called with the signal lock, and that sometimes needs to insert work items. Add a specific worker lock that protects the current work item. Then we can guarantee that the task we're sending a signal is currently processing the exact work we think it is. Reported-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-14 00:43:34 +08:00
return ret;
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
}
static enum io_wq_cancel io_wqe_cancel_work(struct io_wqe *wqe,
struct io_wq_work *cwork)
{
io-wq: shrink io_wq_work a bit Currently we're using 40 bytes for the io_wq_work structure, and 16 of those is the doubly link list node. We don't need doubly linked lists, we always add to tail to keep things ordered, and any other use case is list traversal with deletion. For the deletion case, we can easily support any node deletion by keeping track of the previous entry. This shrinks io_wq_work to 32 bytes, and subsequently io_kiock from io_uring to 216 to 208 bytes. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27 02:59:32 +08:00
struct io_wq_work_node *node, *prev;
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
struct io_wq_work *work;
io-wq: use proper nesting IRQ disabling spinlocks for cancel We don't know what context we'll be called in for cancel, it could very well be with IRQs disabled already. Use the IRQ saving variants of the locking primitives. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-06 04:51:51 +08:00
unsigned long flags;
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
bool found = false;
cwork->flags |= IO_WQ_WORK_CANCEL;
/*
* First check pending list, if we're lucky we can just remove it
* from there. CANCEL_OK means that the work is returned as-new,
* no completion will be posted for it.
*/
io-wq: use proper nesting IRQ disabling spinlocks for cancel We don't know what context we'll be called in for cancel, it could very well be with IRQs disabled already. Use the IRQ saving variants of the locking primitives. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-06 04:51:51 +08:00
spin_lock_irqsave(&wqe->lock, flags);
io-wq: shrink io_wq_work a bit Currently we're using 40 bytes for the io_wq_work structure, and 16 of those is the doubly link list node. We don't need doubly linked lists, we always add to tail to keep things ordered, and any other use case is list traversal with deletion. For the deletion case, we can easily support any node deletion by keeping track of the previous entry. This shrinks io_wq_work to 32 bytes, and subsequently io_kiock from io_uring to 216 to 208 bytes. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27 02:59:32 +08:00
wq_list_for_each(node, prev, &wqe->work_list) {
work = container_of(node, struct io_wq_work, list);
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
if (work == cwork) {
io-wq: shrink io_wq_work a bit Currently we're using 40 bytes for the io_wq_work structure, and 16 of those is the doubly link list node. We don't need doubly linked lists, we always add to tail to keep things ordered, and any other use case is list traversal with deletion. For the deletion case, we can easily support any node deletion by keeping track of the previous entry. This shrinks io_wq_work to 32 bytes, and subsequently io_kiock from io_uring to 216 to 208 bytes. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27 02:59:32 +08:00
wq_node_del(&wqe->work_list, node, prev);
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
found = true;
break;
}
}
io-wq: use proper nesting IRQ disabling spinlocks for cancel We don't know what context we'll be called in for cancel, it could very well be with IRQs disabled already. Use the IRQ saving variants of the locking primitives. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-06 04:51:51 +08:00
spin_unlock_irqrestore(&wqe->lock, flags);
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
if (found) {
work->flags |= IO_WQ_WORK_CANCEL;
work->func(&work);
return IO_WQ_CANCEL_OK;
}
/*
* Now check if a free (going busy) or busy worker has the work
* currently running. If we find it there, we'll return CANCEL_RUNNING
* as an indication that we attempte to signal cancellation. The
* completion will run normally in this case.
*/
rcu_read_lock();
io-wq: ensure free/busy list browsing see all items We have two lists for workers in io-wq, a busy and a free list. For certain operations we want to browse all workers, and we currently do that by browsing the two separate lists. But since these lists are RCU protected, we can potentially miss workers if they move between the two lists while we're browsing them. Add a third list, all_list, that simply holds all workers. A worker is added to that list when it starts, and removed when it exits. This makes the worker iteration cleaner, too. Reported-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-14 04:54:49 +08:00
found = io_wq_for_each_worker(wqe, io_wq_worker_cancel, cwork);
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
rcu_read_unlock();
return found ? IO_WQ_CANCEL_RUNNING : IO_WQ_CANCEL_NOTFOUND;
}
enum io_wq_cancel io_wq_cancel_work(struct io_wq *wq, struct io_wq_work *cwork)
{
enum io_wq_cancel ret = IO_WQ_CANCEL_NOTFOUND;
io-wq: fix handling of NUMA node IDs There are several things that can go wrong in the current code on NUMA systems, especially if not all nodes are online all the time: - If the identifiers of the online nodes do not form a single contiguous block starting at zero, wq->wqes will be too small, and OOB memory accesses will occur e.g. in the loop in io_wq_create(). - If a node comes online between the call to num_online_nodes() and the for_each_node() loop in io_wq_create(), an OOB write will occur. - If a node comes online between io_wq_create() and io_wq_enqueue(), a lookup is performed for an element that doesn't exist, and an OOB read will probably occur. Fix it by: - using nr_node_ids instead of num_online_nodes() for the allocation size; nr_node_ids is calculated by setup_nr_node_ids() to be bigger than the highest node ID that could possibly come online at some point, even if those nodes' identifiers are not a contiguous block - creating workers for all possible CPUs, not just all online ones This is basically what the normal workqueue code also does, as far as I can tell. Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27 02:10:20 +08:00
int node;
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
io-wq: fix handling of NUMA node IDs There are several things that can go wrong in the current code on NUMA systems, especially if not all nodes are online all the time: - If the identifiers of the online nodes do not form a single contiguous block starting at zero, wq->wqes will be too small, and OOB memory accesses will occur e.g. in the loop in io_wq_create(). - If a node comes online between the call to num_online_nodes() and the for_each_node() loop in io_wq_create(), an OOB write will occur. - If a node comes online between io_wq_create() and io_wq_enqueue(), a lookup is performed for an element that doesn't exist, and an OOB read will probably occur. Fix it by: - using nr_node_ids instead of num_online_nodes() for the allocation size; nr_node_ids is calculated by setup_nr_node_ids() to be bigger than the highest node ID that could possibly come online at some point, even if those nodes' identifiers are not a contiguous block - creating workers for all possible CPUs, not just all online ones This is basically what the normal workqueue code also does, as far as I can tell. Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27 02:10:20 +08:00
for_each_node(node) {
struct io_wqe *wqe = wq->wqes[node];
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
ret = io_wqe_cancel_work(wqe, cwork);
if (ret != IO_WQ_CANCEL_NOTFOUND)
break;
}
return ret;
}
struct io_wq_flush_data {
struct io_wq_work work;
struct completion done;
};
static void io_wq_flush_func(struct io_wq_work **workptr)
{
struct io_wq_work *work = *workptr;
struct io_wq_flush_data *data;
data = container_of(work, struct io_wq_flush_data, work);
complete(&data->done);
}
/*
* Doesn't wait for previously queued work to finish. When this completes,
* it just means that previously queued work was started.
*/
void io_wq_flush(struct io_wq *wq)
{
struct io_wq_flush_data data;
io-wq: fix handling of NUMA node IDs There are several things that can go wrong in the current code on NUMA systems, especially if not all nodes are online all the time: - If the identifiers of the online nodes do not form a single contiguous block starting at zero, wq->wqes will be too small, and OOB memory accesses will occur e.g. in the loop in io_wq_create(). - If a node comes online between the call to num_online_nodes() and the for_each_node() loop in io_wq_create(), an OOB write will occur. - If a node comes online between io_wq_create() and io_wq_enqueue(), a lookup is performed for an element that doesn't exist, and an OOB read will probably occur. Fix it by: - using nr_node_ids instead of num_online_nodes() for the allocation size; nr_node_ids is calculated by setup_nr_node_ids() to be bigger than the highest node ID that could possibly come online at some point, even if those nodes' identifiers are not a contiguous block - creating workers for all possible CPUs, not just all online ones This is basically what the normal workqueue code also does, as far as I can tell. Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27 02:10:20 +08:00
int node;
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
io-wq: fix handling of NUMA node IDs There are several things that can go wrong in the current code on NUMA systems, especially if not all nodes are online all the time: - If the identifiers of the online nodes do not form a single contiguous block starting at zero, wq->wqes will be too small, and OOB memory accesses will occur e.g. in the loop in io_wq_create(). - If a node comes online between the call to num_online_nodes() and the for_each_node() loop in io_wq_create(), an OOB write will occur. - If a node comes online between io_wq_create() and io_wq_enqueue(), a lookup is performed for an element that doesn't exist, and an OOB read will probably occur. Fix it by: - using nr_node_ids instead of num_online_nodes() for the allocation size; nr_node_ids is calculated by setup_nr_node_ids() to be bigger than the highest node ID that could possibly come online at some point, even if those nodes' identifiers are not a contiguous block - creating workers for all possible CPUs, not just all online ones This is basically what the normal workqueue code also does, as far as I can tell. Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27 02:10:20 +08:00
for_each_node(node) {
struct io_wqe *wqe = wq->wqes[node];
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
init_completion(&data.done);
INIT_IO_WORK(&data.work, io_wq_flush_func);
io_wq: add get/put_work handlers to io_wq_create() For cancellation, we need to ensure that the work item stays valid for as long as ->cur_work is valid. Right now we can't safely dereference the work item even under the wqe->lock, because while the ->cur_work pointer will remain valid, the work could be completing and be freed in parallel. Only invoke ->get/put_work() on items we know that the caller queued themselves. Add IO_WQ_WORK_INTERNAL for io-wq to use, which is needed when we're queueing a flush item, for instance. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-13 13:31:31 +08:00
data.work.flags |= IO_WQ_WORK_INTERNAL;
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
io_wqe_enqueue(wqe, &data.work);
wait_for_completion(&data.done);
}
}
io-wq: have io_wq_create() take a 'data' argument We currently pass in 4 arguments outside of the bounded size. In preparation for adding one more argument, let's bundle them up in a struct to make it more readable. No functional changes in this patch. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-25 23:49:20 +08:00
struct io_wq *io_wq_create(unsigned bounded, struct io_wq_data *data)
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
{
io-wq: fix handling of NUMA node IDs There are several things that can go wrong in the current code on NUMA systems, especially if not all nodes are online all the time: - If the identifiers of the online nodes do not form a single contiguous block starting at zero, wq->wqes will be too small, and OOB memory accesses will occur e.g. in the loop in io_wq_create(). - If a node comes online between the call to num_online_nodes() and the for_each_node() loop in io_wq_create(), an OOB write will occur. - If a node comes online between io_wq_create() and io_wq_enqueue(), a lookup is performed for an element that doesn't exist, and an OOB read will probably occur. Fix it by: - using nr_node_ids instead of num_online_nodes() for the allocation size; nr_node_ids is calculated by setup_nr_node_ids() to be bigger than the highest node ID that could possibly come online at some point, even if those nodes' identifiers are not a contiguous block - creating workers for all possible CPUs, not just all online ones This is basically what the normal workqueue code also does, as far as I can tell. Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27 02:10:20 +08:00
int ret = -ENOMEM, node;
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
struct io_wq *wq;
io_uring: use kzalloc instead of kcalloc for single-element allocations These allocations are single-element allocations, so don't use the array allocation wrapper for them. Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27 00:39:45 +08:00
wq = kzalloc(sizeof(*wq), GFP_KERNEL);
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
if (!wq)
return ERR_PTR(-ENOMEM);
io-wq: fix handling of NUMA node IDs There are several things that can go wrong in the current code on NUMA systems, especially if not all nodes are online all the time: - If the identifiers of the online nodes do not form a single contiguous block starting at zero, wq->wqes will be too small, and OOB memory accesses will occur e.g. in the loop in io_wq_create(). - If a node comes online between the call to num_online_nodes() and the for_each_node() loop in io_wq_create(), an OOB write will occur. - If a node comes online between io_wq_create() and io_wq_enqueue(), a lookup is performed for an element that doesn't exist, and an OOB read will probably occur. Fix it by: - using nr_node_ids instead of num_online_nodes() for the allocation size; nr_node_ids is calculated by setup_nr_node_ids() to be bigger than the highest node ID that could possibly come online at some point, even if those nodes' identifiers are not a contiguous block - creating workers for all possible CPUs, not just all online ones This is basically what the normal workqueue code also does, as far as I can tell. Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27 02:10:20 +08:00
wq->wqes = kcalloc(nr_node_ids, sizeof(struct io_wqe *), GFP_KERNEL);
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
if (!wq->wqes) {
kfree(wq);
return ERR_PTR(-ENOMEM);
}
io-wq: have io_wq_create() take a 'data' argument We currently pass in 4 arguments outside of the bounded size. In preparation for adding one more argument, let's bundle them up in a struct to make it more readable. No functional changes in this patch. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-25 23:49:20 +08:00
wq->get_work = data->get_work;
wq->put_work = data->put_work;
io_wq: add get/put_work handlers to io_wq_create() For cancellation, we need to ensure that the work item stays valid for as long as ->cur_work is valid. Right now we can't safely dereference the work item even under the wqe->lock, because while the ->cur_work pointer will remain valid, the work could be completing and be freed in parallel. Only invoke ->get/put_work() on items we know that the caller queued themselves. Add IO_WQ_WORK_INTERNAL for io-wq to use, which is needed when we're queueing a flush item, for instance. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-13 13:31:31 +08:00
io-wq: add support for bounded vs unbunded work io_uring supports request types that basically have two different lifetimes: 1) Bounded completion time. These are requests like disk reads or writes, which we know will finish in a finite amount of time. 2) Unbounded completion time. These are generally networked IO, where we have no idea how long they will take to complete. Another example is POLL commands. This patch provides support for io-wq to handle these differently, so we don't starve bounded requests by tying up workers for too long. By default all work is bounded, unless otherwise specified in the work item. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08 02:41:16 +08:00
/* caller must already hold a reference to this */
io-wq: have io_wq_create() take a 'data' argument We currently pass in 4 arguments outside of the bounded size. In preparation for adding one more argument, let's bundle them up in a struct to make it more readable. No functional changes in this patch. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-25 23:49:20 +08:00
wq->user = data->user;
io_uring: async workers should inherit the user creds If we don't inherit the original task creds, then we can confuse users like fuse that pass creds in the request header. See link below on identical aio issue. Link: https://lore.kernel.org/linux-fsdevel/26f0d78e-99ca-2f1b-78b9-433088053a61@scylladb.com/T/#u Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-25 23:52:30 +08:00
wq->creds = data->creds;
io-wq: add support for bounded vs unbunded work io_uring supports request types that basically have two different lifetimes: 1) Bounded completion time. These are requests like disk reads or writes, which we know will finish in a finite amount of time. 2) Unbounded completion time. These are generally networked IO, where we have no idea how long they will take to complete. Another example is POLL commands. This patch provides support for io-wq to handle these differently, so we don't starve bounded requests by tying up workers for too long. By default all work is bounded, unless otherwise specified in the work item. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08 02:41:16 +08:00
io-wq: fix handling of NUMA node IDs There are several things that can go wrong in the current code on NUMA systems, especially if not all nodes are online all the time: - If the identifiers of the online nodes do not form a single contiguous block starting at zero, wq->wqes will be too small, and OOB memory accesses will occur e.g. in the loop in io_wq_create(). - If a node comes online between the call to num_online_nodes() and the for_each_node() loop in io_wq_create(), an OOB write will occur. - If a node comes online between io_wq_create() and io_wq_enqueue(), a lookup is performed for an element that doesn't exist, and an OOB read will probably occur. Fix it by: - using nr_node_ids instead of num_online_nodes() for the allocation size; nr_node_ids is calculated by setup_nr_node_ids() to be bigger than the highest node ID that could possibly come online at some point, even if those nodes' identifiers are not a contiguous block - creating workers for all possible CPUs, not just all online ones This is basically what the normal workqueue code also does, as far as I can tell. Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27 02:10:20 +08:00
for_each_node(node) {
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
struct io_wqe *wqe;
io_uring: use kzalloc instead of kcalloc for single-element allocations These allocations are single-element allocations, so don't use the array allocation wrapper for them. Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27 00:39:45 +08:00
wqe = kzalloc_node(sizeof(struct io_wqe), GFP_KERNEL, node);
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
if (!wqe)
io-wq: fix handling of NUMA node IDs There are several things that can go wrong in the current code on NUMA systems, especially if not all nodes are online all the time: - If the identifiers of the online nodes do not form a single contiguous block starting at zero, wq->wqes will be too small, and OOB memory accesses will occur e.g. in the loop in io_wq_create(). - If a node comes online between the call to num_online_nodes() and the for_each_node() loop in io_wq_create(), an OOB write will occur. - If a node comes online between io_wq_create() and io_wq_enqueue(), a lookup is performed for an element that doesn't exist, and an OOB read will probably occur. Fix it by: - using nr_node_ids instead of num_online_nodes() for the allocation size; nr_node_ids is calculated by setup_nr_node_ids() to be bigger than the highest node ID that could possibly come online at some point, even if those nodes' identifiers are not a contiguous block - creating workers for all possible CPUs, not just all online ones This is basically what the normal workqueue code also does, as far as I can tell. Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27 02:10:20 +08:00
goto err;
wq->wqes[node] = wqe;
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
wqe->node = node;
io-wq: add support for bounded vs unbunded work io_uring supports request types that basically have two different lifetimes: 1) Bounded completion time. These are requests like disk reads or writes, which we know will finish in a finite amount of time. 2) Unbounded completion time. These are generally networked IO, where we have no idea how long they will take to complete. Another example is POLL commands. This patch provides support for io-wq to handle these differently, so we don't starve bounded requests by tying up workers for too long. By default all work is bounded, unless otherwise specified in the work item. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08 02:41:16 +08:00
wqe->acct[IO_WQ_ACCT_BOUND].max_workers = bounded;
atomic_set(&wqe->acct[IO_WQ_ACCT_BOUND].nr_running, 0);
io-wq: have io_wq_create() take a 'data' argument We currently pass in 4 arguments outside of the bounded size. In preparation for adding one more argument, let's bundle them up in a struct to make it more readable. No functional changes in this patch. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-25 23:49:20 +08:00
if (wq->user) {
io-wq: add support for bounded vs unbunded work io_uring supports request types that basically have two different lifetimes: 1) Bounded completion time. These are requests like disk reads or writes, which we know will finish in a finite amount of time. 2) Unbounded completion time. These are generally networked IO, where we have no idea how long they will take to complete. Another example is POLL commands. This patch provides support for io-wq to handle these differently, so we don't starve bounded requests by tying up workers for too long. By default all work is bounded, unless otherwise specified in the work item. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08 02:41:16 +08:00
wqe->acct[IO_WQ_ACCT_UNBOUND].max_workers =
task_rlimit(current, RLIMIT_NPROC);
}
atomic_set(&wqe->acct[IO_WQ_ACCT_UNBOUND].nr_running, 0);
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
wqe->node = node;
wqe->wq = wq;
spin_lock_init(&wqe->lock);
io-wq: shrink io_wq_work a bit Currently we're using 40 bytes for the io_wq_work structure, and 16 of those is the doubly link list node. We don't need doubly linked lists, we always add to tail to keep things ordered, and any other use case is list traversal with deletion. For the deletion case, we can easily support any node deletion by keeping track of the previous entry. This shrinks io_wq_work to 32 bytes, and subsequently io_kiock from io_uring to 216 to 208 bytes. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27 02:59:32 +08:00
INIT_WQ_LIST(&wqe->work_list);
io-wq: remove now redundant struct io_wq_nulls_list Since we don't iterate these lists anymore after commit: e61df66c69b1 ("io-wq: ensure free/busy list browsing see all items") we don't need to retain the nulls value we use for them. That means it's pretty pointless to wrap the hlist_nulls_head in a structure, so get rid of it. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-14 23:00:41 +08:00
INIT_HLIST_NULLS_HEAD(&wqe->free_list, 0);
INIT_HLIST_NULLS_HEAD(&wqe->busy_list, 1);
io-wq: ensure free/busy list browsing see all items We have two lists for workers in io-wq, a busy and a free list. For certain operations we want to browse all workers, and we currently do that by browsing the two separate lists. But since these lists are RCU protected, we can potentially miss workers if they move between the two lists while we're browsing them. Add a third list, all_list, that simply holds all workers. A worker is added to that list when it starts, and removed when it exits. This makes the worker iteration cleaner, too. Reported-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-14 04:54:49 +08:00
INIT_LIST_HEAD(&wqe->all_list);
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
}
init_completion(&wq->done);
/* caller must have already done mmgrab() on this mm */
io-wq: have io_wq_create() take a 'data' argument We currently pass in 4 arguments outside of the bounded size. In preparation for adding one more argument, let's bundle them up in a struct to make it more readable. No functional changes in this patch. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-25 23:49:20 +08:00
wq->mm = data->mm;
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
wq->manager = kthread_create(io_wq_manager, wq, "io_wq_manager");
if (!IS_ERR(wq->manager)) {
wake_up_process(wq->manager);
io-wq: wait for io_wq_create() to setup necessary workers We currently have a race where if setup is really slow, we can be calling io_wq_destroy() before we're done setting up. This will cause the caller to get stuck waiting for the manager to set things up, but the manager already exited. Fix this by doing a sync setup of the manager. This also fixes the case where if we failed creating workers, we'd also get stuck. In practice this race window was really small, as we already wait for the manager to start. Hence someone would have to call io_wq_destroy() after the task has started, but before it started the first loop. The reported test case forked tons of these, which is why it became an issue. Reported-by: syzbot+0f1cc17f85154f400465@syzkaller.appspotmail.com Fixes: 771b53d033e8 ("io-wq: small threadpool implementation for io_uring") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-19 23:37:07 +08:00
wait_for_completion(&wq->done);
if (test_bit(IO_WQ_BIT_ERROR, &wq->state)) {
ret = -ENOMEM;
goto err;
}
reinit_completion(&wq->done);
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
return wq;
}
ret = PTR_ERR(wq->manager);
complete(&wq->done);
io-wq: wait for io_wq_create() to setup necessary workers We currently have a race where if setup is really slow, we can be calling io_wq_destroy() before we're done setting up. This will cause the caller to get stuck waiting for the manager to set things up, but the manager already exited. Fix this by doing a sync setup of the manager. This also fixes the case where if we failed creating workers, we'd also get stuck. In practice this race window was really small, as we already wait for the manager to start. Hence someone would have to call io_wq_destroy() after the task has started, but before it started the first loop. The reported test case forked tons of these, which is why it became an issue. Reported-by: syzbot+0f1cc17f85154f400465@syzkaller.appspotmail.com Fixes: 771b53d033e8 ("io-wq: small threadpool implementation for io_uring") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-19 23:37:07 +08:00
err:
io-wq: fix handling of NUMA node IDs There are several things that can go wrong in the current code on NUMA systems, especially if not all nodes are online all the time: - If the identifiers of the online nodes do not form a single contiguous block starting at zero, wq->wqes will be too small, and OOB memory accesses will occur e.g. in the loop in io_wq_create(). - If a node comes online between the call to num_online_nodes() and the for_each_node() loop in io_wq_create(), an OOB write will occur. - If a node comes online between io_wq_create() and io_wq_enqueue(), a lookup is performed for an element that doesn't exist, and an OOB read will probably occur. Fix it by: - using nr_node_ids instead of num_online_nodes() for the allocation size; nr_node_ids is calculated by setup_nr_node_ids() to be bigger than the highest node ID that could possibly come online at some point, even if those nodes' identifiers are not a contiguous block - creating workers for all possible CPUs, not just all online ones This is basically what the normal workqueue code also does, as far as I can tell. Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27 02:10:20 +08:00
for_each_node(node)
kfree(wq->wqes[node]);
io-wq: wait for io_wq_create() to setup necessary workers We currently have a race where if setup is really slow, we can be calling io_wq_destroy() before we're done setting up. This will cause the caller to get stuck waiting for the manager to set things up, but the manager already exited. Fix this by doing a sync setup of the manager. This also fixes the case where if we failed creating workers, we'd also get stuck. In practice this race window was really small, as we already wait for the manager to start. Hence someone would have to call io_wq_destroy() after the task has started, but before it started the first loop. The reported test case forked tons of these, which is why it became an issue. Reported-by: syzbot+0f1cc17f85154f400465@syzkaller.appspotmail.com Fixes: 771b53d033e8 ("io-wq: small threadpool implementation for io_uring") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-19 23:37:07 +08:00
kfree(wq->wqes);
kfree(wq);
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
return ERR_PTR(ret);
}
static bool io_wq_worker_wake(struct io_worker *worker, void *data)
{
wake_up_process(worker->task);
return false;
}
void io_wq_destroy(struct io_wq *wq)
{
io-wq: fix handling of NUMA node IDs There are several things that can go wrong in the current code on NUMA systems, especially if not all nodes are online all the time: - If the identifiers of the online nodes do not form a single contiguous block starting at zero, wq->wqes will be too small, and OOB memory accesses will occur e.g. in the loop in io_wq_create(). - If a node comes online between the call to num_online_nodes() and the for_each_node() loop in io_wq_create(), an OOB write will occur. - If a node comes online between io_wq_create() and io_wq_enqueue(), a lookup is performed for an element that doesn't exist, and an OOB read will probably occur. Fix it by: - using nr_node_ids instead of num_online_nodes() for the allocation size; nr_node_ids is calculated by setup_nr_node_ids() to be bigger than the highest node ID that could possibly come online at some point, even if those nodes' identifiers are not a contiguous block - creating workers for all possible CPUs, not just all online ones This is basically what the normal workqueue code also does, as far as I can tell. Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27 02:10:20 +08:00
int node;
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
io-wq: wait for io_wq_create() to setup necessary workers We currently have a race where if setup is really slow, we can be calling io_wq_destroy() before we're done setting up. This will cause the caller to get stuck waiting for the manager to set things up, but the manager already exited. Fix this by doing a sync setup of the manager. This also fixes the case where if we failed creating workers, we'd also get stuck. In practice this race window was really small, as we already wait for the manager to start. Hence someone would have to call io_wq_destroy() after the task has started, but before it started the first loop. The reported test case forked tons of these, which is why it became an issue. Reported-by: syzbot+0f1cc17f85154f400465@syzkaller.appspotmail.com Fixes: 771b53d033e8 ("io-wq: small threadpool implementation for io_uring") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-19 23:37:07 +08:00
set_bit(IO_WQ_BIT_EXIT, &wq->state);
if (wq->manager)
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
kthread_stop(wq->manager);
rcu_read_lock();
io-wq: fix handling of NUMA node IDs There are several things that can go wrong in the current code on NUMA systems, especially if not all nodes are online all the time: - If the identifiers of the online nodes do not form a single contiguous block starting at zero, wq->wqes will be too small, and OOB memory accesses will occur e.g. in the loop in io_wq_create(). - If a node comes online between the call to num_online_nodes() and the for_each_node() loop in io_wq_create(), an OOB write will occur. - If a node comes online between io_wq_create() and io_wq_enqueue(), a lookup is performed for an element that doesn't exist, and an OOB read will probably occur. Fix it by: - using nr_node_ids instead of num_online_nodes() for the allocation size; nr_node_ids is calculated by setup_nr_node_ids() to be bigger than the highest node ID that could possibly come online at some point, even if those nodes' identifiers are not a contiguous block - creating workers for all possible CPUs, not just all online ones This is basically what the normal workqueue code also does, as far as I can tell. Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27 02:10:20 +08:00
for_each_node(node)
io_wq_for_each_worker(wq->wqes[node], io_wq_worker_wake, NULL);
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
rcu_read_unlock();
wait_for_completion(&wq->done);
io-wq: fix handling of NUMA node IDs There are several things that can go wrong in the current code on NUMA systems, especially if not all nodes are online all the time: - If the identifiers of the online nodes do not form a single contiguous block starting at zero, wq->wqes will be too small, and OOB memory accesses will occur e.g. in the loop in io_wq_create(). - If a node comes online between the call to num_online_nodes() and the for_each_node() loop in io_wq_create(), an OOB write will occur. - If a node comes online between io_wq_create() and io_wq_enqueue(), a lookup is performed for an element that doesn't exist, and an OOB read will probably occur. Fix it by: - using nr_node_ids instead of num_online_nodes() for the allocation size; nr_node_ids is calculated by setup_nr_node_ids() to be bigger than the highest node ID that could possibly come online at some point, even if those nodes' identifiers are not a contiguous block - creating workers for all possible CPUs, not just all online ones This is basically what the normal workqueue code also does, as far as I can tell. Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27 02:10:20 +08:00
for_each_node(node)
kfree(wq->wqes[node]);
io-wq: small threadpool implementation for io_uring This adds support for io-wq, a smaller and specialized thread pool implementation. This is meant to replace workqueues for io_uring. Among the reasons for this addition are: - We can assign memory context smarter and more persistently if we manage the life time of threads. - We can drop various work-arounds we have in io_uring, like the async_list. - We can implement hashed work insertion, to manage concurrency of buffered writes without needing a) an extra workqueue, or b) needlessly making the concurrency of said workqueue very low which hurts performance of multiple buffered file writers. - We can implement cancel through signals, for cancelling interruptible work like read/write (or send/recv) to/from sockets. - We need the above cancel for being able to assign and use file tables from a process. - We can implement a more thorough cancel operation in general. - We need it to move towards a syslet/threadlet model for even faster async execution. For that we need to take ownership of the used threads. This list is just off the top of my head. Performance should be the same, or better, at least that's what I've seen in my testing. io-wq supports basic NUMA functionality, setting up a pool per node. io-wq hooks up to the scheduler schedule in/out just like workqueue and uses that to drive the need for more/less workers. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-23 00:25:58 +08:00
kfree(wq->wqes);
kfree(wq);
}
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