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authorJack Wang <jinpu.wang@ionos.com>2023-07-05 13:32:27 +0200
committerSong Liu <song@kernel.org>2023-07-27 00:13:30 -0700
commit21bd9a68fef47c4f0e951be9a6fac9745cee1bab (patch)
treed69ed66090a034c81c0cd33713f1aa44f735db1d /drivers/md
parente24ed04389f9619e0aaef615a8948633c182a8b0 (diff)
md/raid1: Avoid lock contention from wake_up()
wake_up is called unconditionally in a few paths such as make_request(), which cause lock contention under high concurrency workload like below raid1_end_write_request wake_up __wake_up_common_lock spin_lock_irqsave Improve performance by only call wake_up() if waitqueue is not 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 2 ramdisk in raid1 on a Intel Broadwell 56 cores server. Before this patch With this patch READ BW=4621MB/s BW=7337MB/s WRITE BW=1980MB/s BW=3144MB/s The patch is inspired by Yu Kuai's change for raid10: https://lore.kernel.org/r/20230621105728.1268542-1-yukuai1@huaweicloud.com Cc: Yu Kuai <yukuai3@huawei.com> Signed-off-by: Jack Wang <jinpu.wang@ionos.com> Reviewed-by: Yu Kuai <yukuai3@huawei.com> Link: https://lore.kernel.org/r/20230705113227.148494-1-jinpu.wang@ionos.com Signed-off-by: Song Liu <song@kernel.org>
Diffstat (limited to 'drivers/md')
-rw-r--r--drivers/md/raid1.c18
1 files changed, 12 insertions, 6 deletions
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index a68c9cccbf0d..23d211969565 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -789,11 +789,17 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect
return best_disk;
}
+static void wake_up_barrier(struct r1conf *conf)
+{
+ if (wq_has_sleeper(&conf->wait_barrier))
+ wake_up(&conf->wait_barrier);
+}
+
static void flush_bio_list(struct r1conf *conf, struct bio *bio)
{
/* flush any pending bitmap writes to disk before proceeding w/ I/O */
raid1_prepare_flush_writes(conf->mddev->bitmap);
- wake_up(&conf->wait_barrier);
+ wake_up_barrier(conf);
while (bio) { /* submit pending writes */
struct bio *next = bio->bi_next;
@@ -970,7 +976,7 @@ static bool _wait_barrier(struct r1conf *conf, int idx, bool nowait)
* In case freeze_array() is waiting for
* get_unqueued_pending() == extra
*/
- wake_up(&conf->wait_barrier);
+ wake_up_barrier(conf);
/* Wait for the barrier in same barrier unit bucket to drop. */
/* Return false when nowait flag is set */
@@ -1013,7 +1019,7 @@ static bool wait_read_barrier(struct r1conf *conf, sector_t sector_nr, bool nowa
* In case freeze_array() is waiting for
* get_unqueued_pending() == extra
*/
- wake_up(&conf->wait_barrier);
+ wake_up_barrier(conf);
/* Wait for array to be unfrozen */
/* Return false when nowait flag is set */
@@ -1042,7 +1048,7 @@ static bool wait_barrier(struct r1conf *conf, sector_t sector_nr, bool nowait)
static void _allow_barrier(struct r1conf *conf, int idx)
{
atomic_dec(&conf->nr_pending[idx]);
- wake_up(&conf->wait_barrier);
+ wake_up_barrier(conf);
}
static void allow_barrier(struct r1conf *conf, sector_t sector_nr)
@@ -1171,7 +1177,7 @@ static void raid1_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;
@@ -1574,7 +1580,7 @@ static void raid1_write_request(struct mddev *mddev, struct bio *bio,
r1_bio_write_done(r1_bio);
/* In case raid1d snuck in to freeze_array */
- wake_up(&conf->wait_barrier);
+ wake_up_barrier(conf);
}
static bool raid1_make_request(struct mddev *mddev, struct bio *bio)