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authorYu Kuai <yukuai3@huawei.com>2023-06-21 18:57:28 +0800
committerSong Liu <song@kernel.org>2023-06-23 09:41:50 -0700
commita8d5fdd4d2702d0c7ec125bd3bbce3fc589afa67 (patch)
treeba89c5dc6f8ca44798d01ef22d559304c8cc830d /drivers/md
parent4934b6401a812f9fe368e7d2d091cd1d120ea262 (diff)
raid10: avoid spin_lock from fastpath from raid10_unplug()
Commit 0c0be98bbe67 ("md/raid10: prevent unnecessary calls to wake_up() in fast path") missed one place, for example, with: fio -direct=1 -rw=write/randwrite -iodepth=1 ... Plug and unplug are called for each io, then wake_up() from raid10_unplug() will cause lock contention as well. Avoid this contention by using wake_up_barrier() instead of wake_up(), where spin_lock is not held if waitqueue is empty. Fio test script: [global] name=random reads and writes ioengine=libaio direct=1 readwrite=randrw rwmixread=70 iodepth=64 buffered=0 filename=/dev/md0 size=1G runtime=30 time_based randrepeat=0 norandommap refill_buffers ramp_time=10 bs=4k numjobs=400 group_reporting=1 [job1] Test result with ramdisk raid10(By Ali): Before this patch With this patch READ IOPS=2033k IOPS=3642k WRITE IOPS=871k IOPS=1561K By the way, in this scenario, blk_plug_cb() will be allocated and freed for each io, this seems need to be optimized as well. Reported-and-tested-by: Ali Gholami Rudi <aligrudi@gmail.com> Closes: https://lore.kernel.org/all/20231606122233@laper.mirepesht/ Signed-off-by: Yu Kuai <yukuai3@huawei.com> Signed-off-by: Song Liu <song@kernel.org> Link: https://lore.kernel.org/r/20230621105728.1268542-1-yukuai1@huaweicloud.com
Diffstat (limited to 'drivers/md')
-rw-r--r--drivers/md/raid10.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 79067769e44b..5051149e27bb 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1118,7 +1118,7 @@ static void raid10_unplug(struct blk_plug_cb *cb, bool from_schedule)
spin_lock_irq(&conf->device_lock);
bio_list_merge(&conf->pending_bio_list, &plug->pending);
spin_unlock_irq(&conf->device_lock);
- wake_up(&conf->wait_barrier);
+ wake_up_barrier(conf);
md_wakeup_thread(mddev->thread);
kfree(plug);
return;
@@ -1127,7 +1127,7 @@ static void raid10_unplug(struct blk_plug_cb *cb, bool from_schedule)
/* we aren't scheduling, so we can do the write-out directly. */
bio = bio_list_get(&plug->pending);
raid1_prepare_flush_writes(mddev->bitmap);
- wake_up(&conf->wait_barrier);
+ wake_up_barrier(conf);
while (bio) { /* submit pending writes */
struct bio *next = bio->bi_next;