| Message ID | 20230621105728.1268542-1-yukuai1@huaweicloud.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] raid10: avoid spin_lock from fastpath from raid10_unplug() | expand |
On Tue, Jun 20, 2023 at 7:59 PM Yu Kuai <yukuai1@huaweicloud.com> wrote: > > From: Yu Kuai <yukuai3@huawei.com> > > 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> Applied to md-next. Thanks, Song > --- > Changes in v2: > - update commit message; > > drivers/md/raid10.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c > index d0de8c9fb3cf..fbaaa5e05edc 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; > -- > 2.39.2 >
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index d0de8c9fb3cf..fbaaa5e05edc 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;