From a2aebe03be60ae4da03507a00d60211d5e0327c3 Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Thu, 24 Apr 2008 22:10:42 +0100 Subject: [PATCH] dm raid1: use timer This patch replaces the schedule() in the main kmirrord thread with a timer. The schedule() could introduce an unwanted delay when work is ready to be processed. The code instead calls wake() when there's work to be done immediately, and delayed_wake() after a failure to give a short delay before retrying. Signed-off-by: Mikulas Patocka Signed-off-by: Alasdair G Kergon --- drivers/md/dm-raid1.c | 48 +++++++++++++++++++++++++------------------ 1 file changed, 28 insertions(+), 20 deletions(-) diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c index 6692e5a84bb1..3b9532fc294c 100644 --- a/drivers/md/dm-raid1.c +++ b/drivers/md/dm-raid1.c @@ -154,6 +154,9 @@ struct mirror_set { struct workqueue_struct *kmirrord_wq; struct work_struct kmirrord_work; + struct timer_list timer; + unsigned long timer_pending; + struct work_struct trigger_event; unsigned int nr_mirrors; @@ -178,6 +181,25 @@ static void wake(struct mirror_set *ms) queue_work(ms->kmirrord_wq, &ms->kmirrord_work); } +static void delayed_wake_fn(unsigned long data) +{ + struct mirror_set *ms = (struct mirror_set *) data; + + clear_bit(0, &ms->timer_pending); + wake(ms); +} + +static void delayed_wake(struct mirror_set *ms) +{ + if (test_and_set_bit(0, &ms->timer_pending)) + return; + + ms->timer.expires = jiffies + HZ / 5; + ms->timer.data = (unsigned long) ms; + ms->timer.function = delayed_wake_fn; + add_timer(&ms->timer); +} + /* FIXME move this */ static void queue_bio(struct mirror_set *ms, struct bio *bio, int rw); @@ -1180,6 +1202,7 @@ static void do_writes(struct mirror_set *ms, struct bio_list *writes) spin_lock_irq(&ms->lock); bio_list_merge(&ms->failures, &sync); spin_unlock_irq(&ms->lock); + wake(ms); } else while ((bio = bio_list_pop(&sync))) do_write(ms, bio); @@ -1239,7 +1262,7 @@ static void do_failures(struct mirror_set *ms, struct bio_list *failures) bio_list_merge(&ms->failures, failures); spin_unlock_irq(&ms->lock); - wake(ms); + delayed_wake(ms); } static void trigger_event(struct work_struct *work) @@ -1253,7 +1276,7 @@ static void trigger_event(struct work_struct *work) /*----------------------------------------------------------------- * kmirrord *---------------------------------------------------------------*/ -static int _do_mirror(struct work_struct *work) +static void do_mirror(struct work_struct *work) { struct mirror_set *ms =container_of(work, struct mirror_set, kmirrord_work); @@ -1274,24 +1297,6 @@ static int _do_mirror(struct work_struct *work) do_reads(ms, &reads); do_writes(ms, &writes); do_failures(ms, &failures); - - return (ms->failures.head) ? 1 : 0; -} - -static void do_mirror(struct work_struct *work) -{ - /* - * If _do_mirror returns 1, we give it - * another shot. This helps for cases like - * 'suspend' where we call flush_workqueue - * and expect all work to be finished. If - * a failure happens during a suspend, we - * couldn't issue a 'wake' because it would - * not be honored. Therefore, we return '1' - * from _do_mirror, and retry here. - */ - while (_do_mirror(work)) - schedule(); } @@ -1545,6 +1550,8 @@ static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv) goto err_free_context; } INIT_WORK(&ms->kmirrord_work, do_mirror); + init_timer(&ms->timer); + ms->timer_pending = 0; INIT_WORK(&ms->trigger_event, trigger_event); r = parse_features(ms, argc, argv, &args_used); @@ -1587,6 +1594,7 @@ static void mirror_dtr(struct dm_target *ti) { struct mirror_set *ms = (struct mirror_set *) ti->private; + del_timer_sync(&ms->timer); flush_workqueue(ms->kmirrord_wq); dm_kcopyd_client_destroy(ms->kcopyd_client); destroy_workqueue(ms->kmirrord_wq); -- 2.20.1