Commit Graph

229 Commits

Author SHA1 Message Date
Benjamin Coddington
ed0172af5d SUNRPC: Fix a race to wake a sync task
We've observed NFS clients with sync tasks sleeping in __rpc_execute
waiting on RPC_TASK_QUEUED that have not responded to a wake-up from
rpc_make_runnable().  I suspect this problem usually goes unnoticed,
because on a busy client the task will eventually be re-awoken by another
task completion or xprt event.  However, if the state manager is draining
the slot table, a sync task missing a wake-up can result in a hung client.

We've been able to prove that the waker in rpc_make_runnable() successfully
calls wake_up_bit() (ie- there's no race to tk_runstate), but the
wake_up_bit() call fails to wake the waiter.  I suspect the waker is
missing the load of the bit's wait_queue_head, so waitqueue_active() is
false.  There are some very helpful comments about this problem above
wake_up_bit(), prepare_to_wait(), and waitqueue_active().

Fix this by inserting smp_mb__after_atomic() before the wake_up_bit(),
which pairs with prepare_to_wait() calling set_current_state().

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2024-07-18 10:49:12 -04:00
Trond Myklebust
d180891fba SUNRPC: Don't change task->tk_status after the call to rpc_exit_task
Some calls to rpc_exit_task() may deliberately change the value of
task->tk_status, for instance because it gets checked by the RPC call's
rpc_release() callback. That makes it wrong to reset the value to
task->tk_rpc_status.
In particular this causes a bug where the rpc_call_done() callback tries
to fail over a set of pNFS/flexfiles writes to a different IP address,
but the reset of task->tk_status causes nfs_commit_release_pages() to
immediately mark the file as having a fatal error.

Fixes: 39494194f9 ("SUNRPC: Fix races with rpc_killall_tasks()")
Cc: stable@vger.kernel.org # 6.1.x
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2023-05-19 16:50:05 -04:00
Dai Ngo
691d0b7820 SUNRPC: remove the maximum number of retries in call_bind_status
Currently call_bind_status places a hard limit of 3 to the number of
retries on EACCES error. This limit was done to prevent NLM unlock
requests from being hang forever when the server keeps returning garbage.
However this change causes problem for cases when NLM service takes
longer than 9 seconds to register with the port mapper after a restart.

This patch removes this hard coded limit and let the RPC handles
the retry based on the standard hard/soft task semantics.

Fixes: 0b760113a3 ("NLM: Don't hang forever on NLM unlock requests")
Reported-by: Helen Chao <helen.chao@oracle.com>
Tested-by: Helen Chao <helen.chao@oracle.com>
Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2023-04-19 17:06:02 -04:00
Linus Torvalds
66b8345585 NFS Client Updates for Linux 6.1
- New Features:
   - Add NFSv4.2 xattr tracepoints
   - Replace xprtiod WQ in rpcrdma
   - Flexfiles cancels I/O on layout recall or revoke
 
 - Bugfixes and Cleanups:
   - Directly use ida_alloc() / ida_free()
   - Don't open-code max_t()
   - Prefer using strscpy over strlcpy
   - Remove unused forward declarations
   - Always return layout states on flexfiles layout return
   - Have LISTXATTR treat NFS4ERR_NOXATTR as an empty reply instead of error
   - Allow more xprtrdma memory allocations to fail without triggering a reclaim
   - Various other xprtrdma clean ups
   - Fix rpc_killall_tasks() races
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Merge tag 'nfs-for-6.1-1' of git://git.linux-nfs.org/projects/anna/linux-nfs

Pull NFS client updates from Anna Schumaker:
 "New Features:
   - Add NFSv4.2 xattr tracepoints
   - Replace xprtiod WQ in rpcrdma
   - Flexfiles cancels I/O on layout recall or revoke

  Bugfixes and Cleanups:
   - Directly use ida_alloc() / ida_free()
   - Don't open-code max_t()
   - Prefer using strscpy over strlcpy
   - Remove unused forward declarations
   - Always return layout states on flexfiles layout return
   - Have LISTXATTR treat NFS4ERR_NOXATTR as an empty reply instead of
     error
   - Allow more xprtrdma memory allocations to fail without triggering a
     reclaim
   - Various other xprtrdma clean ups
   - Fix rpc_killall_tasks() races"

* tag 'nfs-for-6.1-1' of git://git.linux-nfs.org/projects/anna/linux-nfs: (27 commits)
  NFSv4/flexfiles: Cancel I/O if the layout is recalled or revoked
  SUNRPC: Add API to force the client to disconnect
  SUNRPC: Add a helper to allow pNFS drivers to selectively cancel RPC calls
  SUNRPC: Fix races with rpc_killall_tasks()
  xprtrdma: Fix uninitialized variable
  xprtrdma: Prevent memory allocations from driving a reclaim
  xprtrdma: Memory allocation should be allowed to fail during connect
  xprtrdma: MR-related memory allocation should be allowed to fail
  xprtrdma: Clean up synopsis of rpcrdma_regbuf_alloc()
  xprtrdma: Clean up synopsis of rpcrdma_req_create()
  svcrdma: Clean up RPCRDMA_DEF_GFP
  SUNRPC: Replace the use of the xprtiod WQ in rpcrdma
  NFSv4.2: Add a tracepoint for listxattr
  NFSv4.2: Add tracepoints for getxattr, setxattr, and removexattr
  NFSv4.2: Move TRACE_DEFINE_ENUM(NFS4_CONTENT_*) under CONFIG_NFS_V4_2
  NFSv4.2: Add special handling for LISTXATTR receiving NFS4ERR_NOXATTR
  nfs: remove nfs_wait_atomic_killable() and nfs_write_prepare() declaration
  NFSv4: remove nfs4_renewd_prepare_shutdown() declaration
  fs/nfs/pnfs_nfs.c: fix spelling typo and syntax error in comment
  NFSv4/pNFS: Always return layout stats on layout return for flexfiles
  ...
2022-10-13 09:58:42 -07:00
Trond Myklebust
f8423909ec SUNRPC: Add a helper to allow pNFS drivers to selectively cancel RPC calls
Add the helper rpc_cancel_tasks(), which uses a caller-defined selection
function to define a set of in-flight RPC calls to cancel. This is
mainly intended for pNFS drivers which are subject to a layout recall,
and which may therefore want to cancel all pending I/O using that layout
in order to redrive it after the layout recall has been satisfied.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2022-10-06 09:52:09 -04:00
Trond Myklebust
39494194f9 SUNRPC: Fix races with rpc_killall_tasks()
Ensure that we immediately call rpc_exit_task() after waking up, and
that the tk_rpc_status cannot get clobbered by some other function.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2022-10-06 09:52:09 -04:00
Peter Zijlstra
f5d39b0208 freezer,sched: Rewrite core freezer logic
Rewrite the core freezer to behave better wrt thawing and be simpler
in general.

By replacing PF_FROZEN with TASK_FROZEN, a special block state, it is
ensured frozen tasks stay frozen until thawed and don't randomly wake
up early, as is currently possible.

As such, it does away with PF_FROZEN and PF_FREEZER_SKIP, freeing up
two PF_flags (yay!).

Specifically; the current scheme works a little like:

	freezer_do_not_count();
	schedule();
	freezer_count();

And either the task is blocked, or it lands in try_to_freezer()
through freezer_count(). Now, when it is blocked, the freezer
considers it frozen and continues.

However, on thawing, once pm_freezing is cleared, freezer_count()
stops working, and any random/spurious wakeup will let a task run
before its time.

That is, thawing tries to thaw things in explicit order; kernel
threads and workqueues before doing bringing SMP back before userspace
etc.. However due to the above mentioned races it is entirely possible
for userspace tasks to thaw (by accident) before SMP is back.

This can be a fatal problem in asymmetric ISA architectures (eg ARMv9)
where the userspace task requires a special CPU to run.

As said; replace this with a special task state TASK_FROZEN and add
the following state transitions:

	TASK_FREEZABLE	-> TASK_FROZEN
	__TASK_STOPPED	-> TASK_FROZEN
	__TASK_TRACED	-> TASK_FROZEN

The new TASK_FREEZABLE can be set on any state part of TASK_NORMAL
(IOW. TASK_INTERRUPTIBLE and TASK_UNINTERRUPTIBLE) -- any such state
is already required to deal with spurious wakeups and the freezer
causes one such when thawing the task (since the original state is
lost).

The special __TASK_{STOPPED,TRACED} states *can* be restored since
their canonical state is in ->jobctl.

With this, frozen tasks need an explicit TASK_FROZEN wakeup and are
free of undue (early / spurious) wakeups.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/20220822114649.055452969@infradead.org
2022-09-07 21:53:50 +02:00
Trond Myklebust
4b8dbdfbc5 SUNRPC: Fix an RPC/RDMA performance regression
Use the standard gfp mask instead of using GFP_NOWAIT. The latter causes
issues when under memory pressure.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2022-07-10 19:00:53 -04:00
Trond Myklebust
25cf32ad5d SUNRPC: Handle allocation failure in rpc_new_task()
If the call to rpc_alloc_task() fails, then ensure that the calldata is
released, and that rpc_run_task() and rpc_run_bc_task() bail out early.

Reported-by: NeilBrown <neilb@suse.de>
Fixes: 910ad38697 ("NFS: Fix memory allocation in rpc_alloc_task()")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2022-04-07 16:20:00 -04:00
Trond Myklebust
910ad38697 NFS: Fix memory allocation in rpc_alloc_task()
As for rpc_malloc(), we first try allocating from the slab, then fall
back to a non-waiting allocation from the mempool.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2022-03-22 15:52:55 -04:00
Trond Myklebust
33e5c765bc NFS: Fix memory allocation in rpc_malloc()
When in a low memory situation, we do want rpciod to kick off direct
reclaim in the case where that helps, however we don't want it looping
forever in mempool_alloc().
So first try allocating from the slab using GFP_KERNEL | __GFP_NORETRY,
and then fall back to a GFP_NOWAIT allocation from the mempool.

Ditto for rpc_alloc_task()

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2022-03-22 15:52:55 -04:00
NeilBrown
8db55a032a SUNRPC: improve 'swap' handling: scheduling and PF_MEMALLOC
rpc tasks can be marked as RPC_TASK_SWAPPER.  This causes GFP_MEMALLOC
to be used for some allocations.  This is needed in some cases, but not
in all where it is currently provided, and in some where it isn't
provided.

Currently *all* tasks associated with a rpc_client on which swap is
enabled get the flag and hence some GFP_MEMALLOC support.

GFP_MEMALLOC is provided for ->buf_alloc() but only swap-writes need it.
However xdr_alloc_bvec does not get GFP_MEMALLOC - though it often does
need it.

xdr_alloc_bvec is called while the XPRT_LOCK is held.  If this blocks,
then it blocks all other queued tasks.  So this allocation needs
GFP_MEMALLOC for *all* requests, not just writes, when the xprt is used
for any swap writes.

Similarly, if the transport is not connected, that will block all
requests including swap writes, so memory allocations should get
GFP_MEMALLOC if swap writes are possible.

So with this patch:
 1/ we ONLY set RPC_TASK_SWAPPER for swap writes.
 2/ __rpc_execute() sets PF_MEMALLOC while handling any task
    with RPC_TASK_SWAPPER set, or when handling any task that
    holds the XPRT_LOCKED lock on an xprt used for swap.
    This removes the need for the RPC_IS_SWAPPER() test
    in ->buf_alloc handlers.
 3/ xprt_prepare_transmit() sets PF_MEMALLOC after locking
    any task to a swapper xprt.  __rpc_execute() will clear it.
 3/ PF_MEMALLOC is set for all the connect workers.

Reviewed-by: Chuck Lever <chuck.lever@oracle.com> (for xprtrdma parts)
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2022-03-13 12:59:35 -04:00
NeilBrown
a80a846186 SUNRPC: remove scheduling boost for "SWAPPER" tasks.
Currently, tasks marked as "swapper" tasks get put to the front of
non-priority rpc_queues, and are sorted earlier than non-swapper tasks on
the transport's ->xmit_queue.

This is pointless as currently *all* tasks for a mount that has swap
enabled on *any* file are marked as "swapper" tasks.  So the net result
is that the non-priority rpc_queues are reverse-ordered (LIFO).

This scheduling boost is not necessary to avoid deadlocks, and hurts
fairness, so remove it.  If there were a need to expedite some requests,
the tk_priority mechanism is a more appropriate tool.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2022-03-13 12:59:35 -04:00
NeilBrown
c487216bec SUNRPC/call_alloc: async tasks mustn't block waiting for memory
When memory is short, new worker threads cannot be created and we depend
on the minimum one rpciod thread to be able to handle everything.
So it must not block waiting for memory.

mempools are particularly a problem as memory can only be released back
to the mempool by an async rpc task running.  If all available
workqueue threads are waiting on the mempool, no thread is available to
return anything.

rpc_malloc() can block, and this might cause deadlocks.
So check RPC_IS_ASYNC(), rather than RPC_IS_SWAPPER() to determine if
blocking is acceptable.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2022-03-13 12:59:35 -04:00
Trond Myklebust
0adc879406 SUNRPC: Convert GFP_NOFS to GFP_KERNEL
The sections which should not re-enter the filesystem are already
protected with memalloc_nofs_save/restore calls, so it is better to use
GFP_KERNEL in these calls to allow better performance for synchronous
RPC calls.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2022-02-25 18:50:12 -05:00
Chuck Lever
b40887e10d SUNRPC: Trace calls to .rpc_call_done
Introduce a single tracepoint that can replace simple dprintk call
sites in upper layer "rpc_call_done" callbacks. Example:

   kworker/u24:2-1254  [001]   771.026677: rpc_stats_latency:    task:00000001@00000002 xid=0x16a6f3c0 rpcbindv2 GETPORT backlog=446 rtt=101 execute=555
   kworker/u24:2-1254  [001]   771.026677: rpc_task_call_done:   task:00000001@00000002 flags=ASYNC|DYNAMIC|SOFT|SOFTCONN|SENT runstate=RUNNING|ACTIVE status=0 action=rpcb_getport_done
   kworker/u24:2-1254  [001]   771.026678: rpcb_setport:         task:00000001@00000002 status=0 port=20048

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-10-20 18:09:54 -04:00
Chuck Lever
0392dd51f9 SUNRPC: Per-rpc_clnt task PIDs
The current range of RPC task PIDs is 0..65535. That's not adequate
for distinguishing tasks across multiple rpc_clnts running high
throughput workloads.

To help relieve this situation and to reduce the bottleneck of
having a single atomic for assigning all RPC task PIDs, assign task
PIDs per rpc_clnt.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-10-10 11:05:54 +02:00
Trond Myklebust
6dbcbe3f78 SUNRPC: Remove WQ_HIGHPRI from xprtiod
Don't let xprtiod pre-empt softirq.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-10-03 20:49:05 -04:00
Trond Myklebust
47dd8796a3 SUNRPC: Add cond_resched() at the appropriate point in __rpc_execute()
Allow tasks that need to pre-empt rpciod/xprtiod to do so when it is
safe.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-10-03 20:49:05 -04:00
Zhang Xiaoxu
5483b904bf SUNRPC: Should wake up the privileged task firstly.
When find a task from wait queue to wake up, a non-privileged task may
be found out, rather than the privileged. This maybe lead a deadlock
same as commit dfe1fe75e0 ("NFSv4: Fix deadlock between nfs4_evict_inode()
and nfs4_opendata_get_inode()"):

Privileged delegreturn task is queued to privileged list because all
the slots are assigned. If there has no enough slot to wake up the
non-privileged batch tasks(session less than 8 slot), then the privileged
delegreturn task maybe lost waked up because the found out task can't
get slot since the session is on draining.

So we should treate the privileged task as the emergency task, and
execute it as for as we can.

Reported-by: Hulk Robot <hulkci@huawei.com>
Fixes: 5fcdfacc01 ("NFSv4: Return delegations synchronously in evict_inode")
Cc: stable@vger.kernel.org
Signed-off-by: Zhang Xiaoxu <zhangxiaoxu5@huawei.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-06-28 09:34:39 -04:00
Zhang Xiaoxu
fcb170a9d8 SUNRPC: Fix the batch tasks count wraparound.
The 'queue->nr' will wraparound from 0 to 255 when only current
priority queue has tasks. This maybe lead a deadlock same as commit
dfe1fe75e0 ("NFSv4: Fix deadlock between nfs4_evict_inode()
and nfs4_opendata_get_inode()"):

Privileged delegreturn task is queued to privileged list because all
the slots are assigned. When non-privileged task complete and release
the slot, a non-privileged maybe picked out. It maybe allocate slot
failed when the session on draining.

If the 'queue->nr' has wraparound to 255, and no enough slot to
service it, then the privileged delegreturn will lost to wake up.

So we should avoid the wraparound on 'queue->nr'.

Reported-by: Hulk Robot <hulkci@huawei.com>
Fixes: 5fcdfacc01 ("NFSv4: Return delegations synchronously in evict_inode")
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Signed-off-by: Zhang Xiaoxu <zhangxiaoxu5@huawei.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-06-28 09:34:39 -04:00
Benjamin Coddington
f0940f4b32 SUNRPC: Set memalloc_nofs_save() for sync tasks
We could recurse into NFS doing memory reclaim while sending a sync task,
which might result in a deadlock.  Set memalloc_nofs_save for sync task
execution.

Fixes: a1231fda7e ("SUNRPC: Set memalloc_nofs_save() on all rpciod/xprtiod jobs")
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2021-03-08 15:32:16 -05:00
Trond Myklebust
e4c72201b6 SUNRPC: rpc_wake_up() should wake up tasks in the correct order
Currently, we wake up the tasks by priority queue ordering, which means
that we ignore the batching that is supposed to help with QoS issues.

Fixes: c049f8ea9a ("SUNRPC: Remove the bh-safe lock requirement on the rpc_wait_queue->lock")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2020-12-02 14:05:51 -05:00
Chuck Lever
5589cc4778 SUNRPC: Remove remaining dprintks from sched.c
Clean up.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-09-21 10:21:09 -04:00
Chuck Lever
721a1d388b SUNRPC: Remove dprintk call sites in RPC queuing functions
Remove redundant call sites or call sites that are already covered
by tracepoints.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-09-21 10:21:09 -04:00
Chuck Lever
1466c22163 SUNRPC: Clean up RPC scheduler tracepoints
Remove several redundant dprintk call sites, and replace a couple of
potentially useful ones with tracepoints.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-09-21 10:21:09 -04:00
Chuck Lever
7806948753 SUNRPC: Remove debugging instrumentation from xprt_release
These instruments don't appear to add any substantial value.

We already have this at the termination of each RPC:

          iozone-2617  [002]   975.713126: rpc_stats_latency:    task:418@5 xid=0x260eab5d nfsv3 LOOKUP backlog=15 rtt=32 execute=58
          iozone-2617  [002]   975.713127: xprt_release_cong:    task:418@5 snd_task:4294967295 cong=256 cwnd=16384
          iozone-2617  [002]   975.713127: xprt_put_cong:        task:418@5 snd_task:4294967295 cong=0 cwnd=16384

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-09-21 10:21:08 -04:00
Chuck Lever
06e234c613 SUNRPC: Hoist trace_xprtrdma_op_allocate into generic code
Introduce a tracepoint in call_allocate that reports the exact
sizes in the RPC buffer allocation request and the status of the
result. This helps catch problems with XDR buffer provisioning,
and replaces transport-specific debugging instrumentation.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-09-21 10:21:08 -04:00
Trond Myklebust
1fab7dc477 SUNRPC: Don't start a timer on an already queued rpc task
Move the test for whether a task is already queued to prevent
corruption of the timer list in __rpc_sleep_on_priority_timeout().

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2020-04-04 19:59:27 -04:00
Trond Myklebust
7eac52648a SUNRPC: Add a flag to avoid reference counts on credentials
Add a flag to signal to the RPC layer that the credential is already
pinned for the duration of the RPC call.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2020-03-16 08:34:28 -04:00
Chuck Lever
abf8af78a6 SUNRPC: Capture signalled RPC tasks
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-01-15 10:54:31 -05:00
Chuck Lever
a264abad51 SUNRPC: Capture completion of all RPC tasks
RPC tasks on the backchannel never invoke xprt_complete_rqst(), so
there is no way to report their tk_status at completion. Also, any
RPC task that exits via rpc_exit_task() before it is replied to will
also disappear without a trace.

Introduce a trace point that is symmetrical with rpc_task_begin that
captures the termination status of each RPC task.

Sample trace output for callback requests initiated on the server:
   kworker/u8:12-448   [003]   127.025240: rpc_task_end:         task:50@3 flags=ASYNC|DYNAMIC|SOFT|SOFTCONN|SENT runstate=RUNNING|ACTIVE status=0 action=rpc_exit_task
   kworker/u8:12-448   [002]   127.567310: rpc_task_end:         task:51@3 flags=ASYNC|DYNAMIC|SOFT|SOFTCONN|SENT runstate=RUNNING|ACTIVE status=0 action=rpc_exit_task
   kworker/u8:12-448   [001]   130.506817: rpc_task_end:         task:52@3 flags=ASYNC|DYNAMIC|SOFT|SOFTCONN|SENT runstate=RUNNING|ACTIVE status=0 action=rpc_exit_task

Odd, though, that I never see trace_rpc_task_complete, either in the
forward or backchannel. Should it be removed?

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2019-11-22 19:09:38 +01:00
Trond Myklebust
66eb3add45 SUNRPC: Avoid RPC delays when exiting suspend
Jon Hunter: "I have been tracking down another suspend/NFS related
issue where again I am seeing random delays exiting suspend. The delays
can be up to a couple minutes in the worst case and this is causing a
suspend test we have to fail."

Change the use of a deferrable work to a standard delayed one.

Reported-by: Jon Hunter <jonathanh@nvidia.com>
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Fixes: 7e0a0e38fc ("SUNRPC: Replace the queue timer with a delayed work function")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2019-11-06 08:55:02 -05:00
Trond Myklebust
714fbc7388 SUNRPC: RPC level errors should always set task->tk_rpc_status
Ensure that we set task->tk_rpc_status for all RPC level errors so that
the caller can distinguish between those and server reply status errors.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-09-17 15:14:11 -04:00
Chuck Lever
691b45ddbd SUNRPC: Remove rpc_wake_up_queued_task_on_wq()
Clean up: commit c544577dad ("SUNRPC: Clean up transport write
space handling") appears to have removed the last caller of
rpc_wake_up_queued_task_on_wq().

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-08-20 10:02:22 -04:00
Trond Myklebust
a101b043c4 SUNRPC: Fix transport accounting when caller specifies an rpc_xprt
Ensure that we do the required accounting for the round robin queue
when the caller to rpc_init_task() has passed in a transport to be
used.

Reported-by: Olga Kornievskaia <aglo@umich.edu>
Reported-by: Neil Brown <neilb@suse.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2019-07-12 13:14:54 -04:00
Trond Myklebust
347543e640 Merge tag 'nfs-rdma-for-5.3-1' of git://git.linux-nfs.org/projects/anna/linux-nfs
NFSoRDMA client updates for 5.3

New features:
- Add a way to place MRs back on the free list
- Reduce context switching
- Add new trace events

Bugfixes and cleanups:
- Fix a BUG when tracing is enabled with NFSv4.1
- Fix a use-after-free in rpcrdma_post_recvs
- Replace use of xdr_stream_pos in rpcrdma_marshal_req
- Fix occasional transport deadlock
- Fix show_nfs_errors macros, other tracing improvements
- Remove RPCRDMA_REQ_F_PENDING and fr_state
- Various simplifications and refactors
2019-07-12 12:11:01 -04:00
Chuck Lever
675dd90ad0 xprtrdma: Modernize ops->connect
Adapt and apply changes that were made to the TCP socket connect
code. See the following commits for details on the purpose of
these changes:

Commit 7196dbb02e ("SUNRPC: Allow changing of the TCP timeout parameters on the fly")
Commit 3851f1cdb2 ("SUNRPC: Limit the reconnect backoff timer to the max RPC message timeout")
Commit 02910177ae ("SUNRPC: Fix reconnection timeouts")

Some common transport code is moved to xprt.c to satisfy the code
duplication police.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-07-09 10:30:25 -04:00
Trond Myklebust
41adafa02e Merge branch 'bh-remove' 2019-07-06 14:54:51 -04:00
Dave Wysochanski
9dfe52a95a SUNRPC: Move call to rpc_count_iostats before rpc_call_done
For diagnostic purposes, it would be useful to have an rpc_iostats
metric of RPCs completing with tk_status < 0.  Unfortunately,
tk_status is reset inside the rpc_call_done functions for each
operation, and the call to tally the per-op metrics comes after
rpc_call_done.  Refactor the call to rpc_count_iostat earlier in
rpc_exit_task so we can count these RPCs completing in error.

Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2019-07-06 14:54:51 -04:00
Trond Myklebust
c049f8ea9a SUNRPC: Remove the bh-safe lock requirement on the rpc_wait_queue->lock
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2019-07-06 14:54:49 -04:00
Trond Myklebust
7e0a0e38fc SUNRPC: Replace the queue timer with a delayed work function
The queue timer function, which walks the RPC queue in order to locate
candidates for waking up is one of the current constraints against
removing the bh-safe queue spin locks. Replace it with a delayed
work queue, so that we can do the actual rpc task wake ups from an
ordinary process context.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2019-07-06 14:54:48 -04:00
Anna Schumaker
502980e84e Revert "SUNRPC: Declare RPC timers as TIMER_DEFERRABLE"
Jon Hunter reports:
  "I have been noticing intermittent failures with a system suspend test on
   some of our machines that have a NFS mounted root file-system. Bisecting
   this issue points to your commit 431235818b ("SUNRPC: Declare RPC
   timers as TIMER_DEFERRABLE") and reverting this on top of v5.2-rc3 does
   appear to resolve the problem.

   The cause of the suspend failure appears to be a long delay observed
   sometimes when resuming from suspend, and this is causing our test to
   timeout."

This reverts commit 431235818b.

Reported-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-06-21 14:43:42 -04:00
Thomas Gleixner
457c899653 treewide: Add SPDX license identifier for missed files
Add SPDX license identifiers to all files which:

 - Have no license information of any form

 - Have EXPORT_.*_SYMBOL_GPL inside which was used in the
   initial scan/conversion to ignore the file

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

  GPL-2.0-only

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-21 10:50:45 +02:00
Trond Myklebust
431235818b SUNRPC: Declare RPC timers as TIMER_DEFERRABLE
Don't wake idle CPUs only for the purpose of servicing an RPC
queue timeout.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-04-25 14:18:13 -04:00
Trond Myklebust
24a9d9a21e SUNRPC: Simplify queue timeouts using timer_reduce()
Simplify the setting of queue timeouts by using the timer_reduce()
function.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-04-25 14:18:13 -04:00
Trond Myklebust
5efd1876e6 SUNRPC: Fix up tracking of timeouts
Add a helper to ensure that debugfs and friends print out the
correct current task timeout value.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-04-25 14:18:13 -04:00
Trond Myklebust
6b2e685627 SUNRPC: Add function rpc_sleep_on_timeout()
Clean up the RPC task sleep interfaces by replacing the task->tk_timeout
'hidden parameter' to rpc_sleep_on() with a new function that takes an
absolute timeout.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-04-25 14:18:13 -04:00
Trond Myklebust
8357a9b60f SUNRPC: Remove unused argument 'action' from rpc_sleep_on_priority()
None of the callers set the 'action' argument, so let's just remove it.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-04-25 14:18:12 -04:00
Trond Myklebust
87150aaed9 SUNRPC: Refactor rpc_sleep_on()
rpc_sleep_on() does not need to set the task->tk_callback under the
queue lock, so move that out.
Also refactor the check for whether the task is active.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-04-25 14:18:12 -04:00