diff options
| author |   Yu Kuai <yukuai3@huawei.com> | 2022-09-16 19:34:26 +0800 |
|---|---|---|
| committer |   Song Liu <song@kernel.org> | 2022-09-22 00:05:05 -0700 |
| commit | 0c0be98bbe67662a7d2bf8381106bfca0e31ed72 (patch) | |
| tree | 3f345788a58afbb9ab684b17edddb6e47b899fbc | |
| parent | md/raid10: don't modify 'nr_waitng' in wait_barrier() for the case nowait (diff) | |
| download | linux-dev-0c0be98bbe67662a7d2bf8381106bfca0e31ed72.tar.xz linux-dev-0c0be98bbe67662a7d2bf8381106bfca0e31ed72.zip | |
md/raid10: prevent unnecessary calls to wake_up() in fast path
Currently, wake_up() is called unconditionally in fast path such as
raid10_make_request(), which will cause lock contention under high
concurrency:
raid10_make_request
wake_up
__wake_up_common_lock
spin_lock_irqsave
Improve performance by only call wake_up() if waitqueue is not empty
in allow_barrier() and raid10_make_request().
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Acked-by: Guoqing Jiang <guoqing.jiang@linux.dev>
Signed-off-by: Song Liu <song@kernel.org>
| -rw-r--r-- | drivers/md/raid10.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index 834a34274976..461c8a79fb99 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -274,6 +274,12 @@ static void put_buf(struct r10bio *r10_bio) lower_barrier(conf); } +static void wake_up_barrier(struct r10conf *conf) +{ + if (wq_has_sleeper(&conf->wait_barrier)) + wake_up(&conf->wait_barrier); +} + static void reschedule_retry(struct r10bio *r10_bio) { unsigned long flags; @@ -1015,7 +1021,7 @@ static void allow_barrier(struct r10conf *conf) { if ((atomic_dec_and_test(&conf->nr_pending)) || (conf->array_freeze_pending)) - wake_up(&conf->wait_barrier); + wake_up_barrier(conf); } static void freeze_array(struct r10conf *conf, int extra) @@ -1891,7 +1897,7 @@ static bool raid10_make_request(struct mddev *mddev, struct bio *bio) __make_request(mddev, bio, sectors); /* In case raid10d snuck in to freeze_array */ - wake_up(&conf->wait_barrier); + wake_up_barrier(conf); return true; } |