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| author | Pavel Begunkov <asml.silence@gmail.com> | 2023-01-09 17:46:10 +0300 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2023-01-30 01:17:40 +0300 |
| commit | 3181e22fb79910c7071e84a43af93ac89e8a7106 (patch) | |
| tree | e5015f75d3d39aa9301f8b629fb57df742cc1333 /io_uring | |
| parent | bca39f39058567643487cd654970717705784ba3 (diff) | |
| download | linux-3181e22fb79910c7071e84a43af93ac89e8a7106.tar.xz | |
io_uring: wake up optimisations
Flush completions is done either from the submit syscall or by the
task_work, both are in the context of the submitter task, and when it
goes for a single threaded rings like implied by ->task_complete, there
won't be any waiters on ->cq_wait but the master task. That means that
there can be no tasks sleeping on cq_wait while we run
__io_submit_flush_completions() and so waking up can be skipped.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/60ad9768ec74435a0ddaa6eec0ffa7729474f69f.1673274244.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'io_uring')
| -rw-r--r-- | io_uring/io_uring.c | 21 |
1 files changed, 20 insertions, 1 deletions
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index de71730d9051..f2e1dd076d98 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -621,6 +621,25 @@ static inline void __io_cq_unlock_post(struct io_ring_ctx *ctx) io_cqring_wake(ctx); } +static inline void __io_cq_unlock_post_flush(struct io_ring_ctx *ctx) + __releases(ctx->completion_lock) +{ + io_commit_cqring(ctx); + __io_cq_unlock(ctx); + io_commit_cqring_flush(ctx); + + /* + * As ->task_complete implies that the ring is single tasked, cq_wait + * may only be waited on by the current in io_cqring_wait(), but since + * it will re-check the wakeup conditions once we return we can safely + * skip waking it up. + */ + if (!(ctx->flags & IORING_SETUP_DEFER_TASKRUN)) { + smp_mb(); + __io_cqring_wake(ctx); + } +} + void io_cq_unlock_post(struct io_ring_ctx *ctx) __releases(ctx->completion_lock) { @@ -1480,7 +1499,7 @@ static void __io_submit_flush_completions(struct io_ring_ctx *ctx) } } } - __io_cq_unlock_post(ctx); + __io_cq_unlock_post_flush(ctx); if (!wq_list_empty(&ctx->submit_state.compl_reqs)) { io_free_batch_list(ctx, state->compl_reqs.first); |