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8751d15426
Every task_work will try to wake the task to be executed, which causes excessive scheduling and additional overhead. For some tw it's justified, but others won't do much but post a single CQE. When a task waits for multiple cqes, every such task_work will wake it up. Instead, the task may give a hint about how many cqes it waits for, io_req_local_work_add() will compare against it and skip wake ups if #cqes + #tw is not enough to satisfy the waiting condition. Task_work that uses the optimisation should be simple enough and never post more than one CQE. It's also ignored for non DEFER_TASKRUN rings. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/d2b77e99d1e86624d8a69f7037d764b739dcd225.1680782017.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
87 lines
2.3 KiB
C
87 lines
2.3 KiB
C
#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/file.h>
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#include <linux/slab.h>
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#include <linux/net.h>
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#include <linux/io_uring.h>
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#include "io_uring.h"
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#include "notif.h"
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#include "rsrc.h"
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static void io_notif_complete_tw_ext(struct io_kiocb *notif, struct io_tw_state *ts)
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{
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struct io_notif_data *nd = io_notif_to_data(notif);
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struct io_ring_ctx *ctx = notif->ctx;
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if (nd->zc_report && (nd->zc_copied || !nd->zc_used))
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notif->cqe.res |= IORING_NOTIF_USAGE_ZC_COPIED;
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if (nd->account_pages && ctx->user) {
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__io_unaccount_mem(ctx->user, nd->account_pages);
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nd->account_pages = 0;
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}
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io_req_task_complete(notif, ts);
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}
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static void io_tx_ubuf_callback(struct sk_buff *skb, struct ubuf_info *uarg,
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bool success)
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{
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struct io_notif_data *nd = container_of(uarg, struct io_notif_data, uarg);
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struct io_kiocb *notif = cmd_to_io_kiocb(nd);
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if (refcount_dec_and_test(&uarg->refcnt))
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__io_req_task_work_add(notif, IOU_F_TWQ_LAZY_WAKE);
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}
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static void io_tx_ubuf_callback_ext(struct sk_buff *skb, struct ubuf_info *uarg,
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bool success)
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{
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struct io_notif_data *nd = container_of(uarg, struct io_notif_data, uarg);
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if (nd->zc_report) {
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if (success && !nd->zc_used && skb)
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WRITE_ONCE(nd->zc_used, true);
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else if (!success && !nd->zc_copied)
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WRITE_ONCE(nd->zc_copied, true);
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}
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io_tx_ubuf_callback(skb, uarg, success);
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}
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void io_notif_set_extended(struct io_kiocb *notif)
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{
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struct io_notif_data *nd = io_notif_to_data(notif);
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if (nd->uarg.callback != io_tx_ubuf_callback_ext) {
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nd->account_pages = 0;
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nd->zc_report = false;
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nd->zc_used = false;
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nd->zc_copied = false;
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nd->uarg.callback = io_tx_ubuf_callback_ext;
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notif->io_task_work.func = io_notif_complete_tw_ext;
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}
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}
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struct io_kiocb *io_alloc_notif(struct io_ring_ctx *ctx)
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__must_hold(&ctx->uring_lock)
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{
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struct io_kiocb *notif;
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struct io_notif_data *nd;
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if (unlikely(!io_alloc_req(ctx, ¬if)))
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return NULL;
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notif->opcode = IORING_OP_NOP;
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notif->flags = 0;
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notif->file = NULL;
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notif->task = current;
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io_get_task_refs(1);
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notif->rsrc_node = NULL;
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notif->io_task_work.func = io_req_task_complete;
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nd = io_notif_to_data(notif);
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nd->uarg.flags = SKBFL_ZEROCOPY_FRAG | SKBFL_DONT_ORPHAN;
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nd->uarg.callback = io_tx_ubuf_callback;
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refcount_set(&nd->uarg.refcnt, 1);
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return notif;
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}
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