diff options
| author | Pavel Begunkov <asml.silence@gmail.com> | 2023-04-06 14:20:14 +0100 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2023-04-06 16:24:36 -0600 |
| commit | 360cd42c4e95ff06d8d7b0a54e42236c7e7c187f (patch) | |
| tree | 97807acf0f2bcb3ada1ad005bbaa8d95396aceab /io_uring | |
| parent | c66ae3ec38f946edb1776d25c1c8cd63803b8ec3 (diff) | |
io_uring: optimise io_req_local_work_add
Chains of memory accesses are never good for performance.
The req->task->io_uring->in_cancel in io_req_local_work_add() is there
so that when a task is exiting via io_uring_try_cancel_requests() and
starts waiting for completions, it gets woken up by every new task_work
item queued.
Do a little trick by announcing waiting in io_uring_try_cancel_requests(),
making io_req_local_work_add() wake us up. We also need to check for
deferred tw items after prepare_to_wait(TASK_INTERRUPTIBLE);
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/fb11597e9bbcb365901824f8c5c2cf0d6ee100d0.1680782017.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 | 24 |
1 files changed, 16 insertions, 8 deletions
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index 0ea50c46f27f..9bbf58297a0e 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -1335,10 +1335,6 @@ static void io_req_local_work_add(struct io_kiocb *req, unsigned flags) &req->io_task_work.node)); if (!first) { - if (unlikely(atomic_read(&req->task->io_uring->in_cancel))) { - io_move_task_work_from_local(ctx); - return; - } if (ctx->flags & IORING_SETUP_TASKRUN_FLAG) atomic_or(IORING_SQ_TASKRUN, &ctx->rings->sq_flags); if (ctx->has_evfd) @@ -3205,6 +3201,12 @@ static __cold bool io_uring_try_cancel_requests(struct io_ring_ctx *ctx, enum io_wq_cancel cret; bool ret = false; + /* set it so io_req_local_work_add() would wake us up */ + if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) { + atomic_set(&ctx->cq_wait_nr, 1); + smp_mb(); + } + /* failed during ring init, it couldn't have issued any requests */ if (!ctx->rings) return false; @@ -3259,6 +3261,8 @@ __cold void io_uring_cancel_generic(bool cancel_all, struct io_sq_data *sqd) { struct io_uring_task *tctx = current->io_uring; struct io_ring_ctx *ctx; + struct io_tctx_node *node; + unsigned long index; s64 inflight; DEFINE_WAIT(wait); @@ -3280,9 +3284,6 @@ __cold void io_uring_cancel_generic(bool cancel_all, struct io_sq_data *sqd) break; if (!sqd) { - struct io_tctx_node *node; - unsigned long index; - xa_for_each(&tctx->xa, index, node) { /* sqpoll task will cancel all its requests */ if (node->ctx->sq_data) @@ -3305,7 +3306,13 @@ __cold void io_uring_cancel_generic(bool cancel_all, struct io_sq_data *sqd) prepare_to_wait(&tctx->wait, &wait, TASK_INTERRUPTIBLE); io_run_task_work(); io_uring_drop_tctx_refs(current); - + xa_for_each(&tctx->xa, index, node) { + if (!llist_empty(&node->ctx->work_llist)) { + WARN_ON_ONCE(node->ctx->submitter_task && + node->ctx->submitter_task != current); + goto end_wait; + } + } /* * If we've seen completions, retry without waiting. This * avoids a race where a completion comes in before we did @@ -3313,6 +3320,7 @@ __cold void io_uring_cancel_generic(bool cancel_all, struct io_sq_data *sqd) */ if (inflight == tctx_inflight(tctx, !cancel_all)) schedule(); +end_wait: finish_wait(&tctx->wait, &wait); } while (1); |