diff options
| author | Pavel Begunkov <asml.silence@gmail.com> | 2021-04-13 04:58:45 +0300 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2021-04-13 18:37:55 +0300 |
| commit | e9979b36a467dcdb2073ec8391a2c167971bee46 (patch) | |
| tree | ab3eab8f8f49fcc2e9ddaf937c33015acb95b11e /fs/io_uring.c | |
| parent | cce4b8b0ce1f9fdf67f4f73ed12a2da2a085d5e3 (diff) | |
| download | linux-e9979b36a467dcdb2073ec8391a2c167971bee46.tar.xz | |
io_uring: skip futile iopoll iterations
The only way to get out of io_iopoll_getevents() and continue iterating
is to have empty iopoll_list, otherwise the main loop would just exit.
So, instead of the unlock on 8th time heuristic, do that based on
iopoll_list.
Also, as no one can add new requests to iopoll_list while
io_iopoll_check() hold uring_lock, it's useless to spin with the list
empty, return in that case.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/5b8ebe84f5fff7ffa1f708952dfef7fc78b668e2.1618278933.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'fs/io_uring.c')
| -rw-r--r-- | fs/io_uring.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c index 3632b5a4f13f..ffcb3ec4de95 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -2385,7 +2385,7 @@ static void io_iopoll_try_reap_events(struct io_ring_ctx *ctx) static int io_iopoll_check(struct io_ring_ctx *ctx, long min) { unsigned int nr_events = 0; - int iters = 0, ret = 0; + int ret = 0; /* * We disallow the app entering submit/complete with polling, but we @@ -2414,10 +2414,13 @@ static int io_iopoll_check(struct io_ring_ctx *ctx, long min) * forever, while the workqueue is stuck trying to acquire the * very same mutex. */ - if (!(++iters & 7)) { + if (list_empty(&ctx->iopoll_list)) { mutex_unlock(&ctx->uring_lock); io_run_task_work(); mutex_lock(&ctx->uring_lock); + + if (list_empty(&ctx->iopoll_list)) + break; } ret = io_iopoll_getevents(ctx, &nr_events, min); |