From: Jens Axboe <[email protected]>
To: [email protected]
Cc: Pavel Begunkov <[email protected]>, Jens Axboe <[email protected]>
Subject: [PATCH 21/33] io_uring: replace cmpxchg in fallback with xchg
Date: Wed, 3 Mar 2021 17:26:48 -0700 [thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
From: Pavel Begunkov <[email protected]>
io_run_ctx_fallback() can use xchg() instead of cmpxchg(). It's simpler
and faster.
Signed-off-by: Pavel Begunkov <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
---
fs/io_uring.c | 8 ++------
1 file changed, 2 insertions(+), 6 deletions(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index befa0f4dd575..5bd039aa97bb 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -8484,15 +8484,11 @@ static int io_remove_personalities(int id, void *p, void *data)
static bool io_run_ctx_fallback(struct io_ring_ctx *ctx)
{
- struct callback_head *work, *head, *next;
+ struct callback_head *work, *next;
bool executed = false;
do {
- do {
- head = NULL;
- work = READ_ONCE(ctx->exit_task_work);
- } while (cmpxchg(&ctx->exit_task_work, work, head) != work);
-
+ work = xchg(&ctx->exit_task_work, NULL);
if (!work)
break;
--
2.30.1
next prev parent reply other threads:[~2021-03-04 1:10 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-04 0:26 [PATCHSET 0/33] Fixes queued up for 5.12 Jens Axboe
2021-03-04 0:26 ` [PATCH 01/33] io-wq: wait for worker startup when forking a new one Jens Axboe
2021-03-04 0:26 ` [PATCH 02/33] io-wq: have manager wait for all workers to exit Jens Axboe
2021-03-04 0:26 ` [PATCH 03/33] io-wq: don't ask for a new worker if we're exiting Jens Axboe
2021-03-04 0:26 ` [PATCH 04/33] io-wq: rename wq->done completion to wq->started Jens Axboe
2021-03-04 0:26 ` [PATCH 05/33] io-wq: wait for manager exit on wq destroy Jens Axboe
2021-03-04 0:26 ` [PATCH 06/33] io-wq: fix double put of 'wq' in error path Jens Axboe
2021-03-04 0:26 ` [PATCH 07/33] io_uring: SQPOLL stop error handling fixes Jens Axboe
2021-03-04 0:26 ` [PATCH 08/33] io_uring: run fallback on cancellation Jens Axboe
2021-03-04 0:26 ` [PATCH 09/33] io_uring: don't use complete_all() on SQPOLL thread exit Jens Axboe
2021-03-04 0:26 ` [PATCH 10/33] io-wq: provide an io_wq_put_and_exit() helper Jens Axboe
2021-03-04 0:26 ` [PATCH 11/33] io_uring: fix race condition in task_work add and clear Jens Axboe
2021-03-04 0:26 ` [PATCH 12/33] io_uring: signal worker thread unshare Jens Axboe
2021-03-04 12:15 ` Stefan Metzmacher
2021-03-04 14:05 ` Jens Axboe
2021-03-04 0:26 ` [PATCH 13/33] io_uring: warn on not destroyed io-wq Jens Axboe
2021-03-04 0:26 ` [PATCH 14/33] io_uring: destroy io-wq on exec Jens Axboe
2021-03-04 0:26 ` [PATCH 15/33] io_uring: remove unused argument 'tsk' from io_req_caches_free() Jens Axboe
2021-03-04 0:26 ` [PATCH 16/33] io_uring: kill unnecessary REQ_F_WORK_INITIALIZED checks Jens Axboe
2021-03-04 0:26 ` [PATCH 17/33] io_uring: move cred assignment into io_issue_sqe() Jens Axboe
2021-03-04 0:26 ` [PATCH 18/33] io_uring: kill unnecessary io_run_ctx_fallback() in io_ring_exit_work() Jens Axboe
2021-03-04 0:26 ` [PATCH 19/33] io_uring: kill io_uring_flush() Jens Axboe
2021-03-04 0:26 ` [PATCH 20/33] io_uring: fix __tctx_task_work() ctx race Jens Axboe
2021-03-04 0:26 ` Jens Axboe [this message]
2021-03-04 0:26 ` [PATCH 22/33] io_uring: ensure that SQPOLL thread is started for exit Jens Axboe
2021-03-04 0:26 ` [PATCH 23/33] io_uring: ignore double poll add on the same waitqueue head Jens Axboe
2021-03-04 0:26 ` [PATCH 24/33] io_uring: kill sqo_dead and sqo submission halting Jens Axboe
2021-03-04 0:26 ` [PATCH 25/33] io_uring: remove sqo_task Jens Axboe
2021-03-04 0:26 ` [PATCH 26/33] io-wq: fix error path leak of buffered write hash map Jens Axboe
2021-03-04 0:26 ` [PATCH 27/33] io_uring: fix -EAGAIN retry with IOPOLL Jens Axboe
2021-03-04 0:26 ` [PATCH 28/33] io_uring: choose right tctx->io_wq for try cancel Jens Axboe
2021-03-04 0:26 ` [PATCH 29/33] io_uring: inline io_req_clean_work() Jens Axboe
2021-03-04 0:26 ` [PATCH 30/33] io_uring: inline __io_queue_async_work() Jens Axboe
2021-03-04 0:26 ` [PATCH 31/33] io_uring: remove extra in_idle wake up Jens Axboe
2021-03-04 0:26 ` [PATCH 32/33] io_uring: ensure that threads freeze on suspend Jens Axboe
2021-03-04 0:27 ` [PATCH 33/33] io-wq: ensure all pending work is canceled on exit Jens Axboe
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