From 060b0689f5df7e87641c820a605c779149da33ef Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Fri, 4 Nov 2016 16:46:03 +1100 Subject: [PATCH] md: perform async updates for metadata where possible. When adding devices to, or removing device from, an array we need to update the metadata. However we don't need to do it synchronously as data integrity doesn't depend on these changes being recorded instantly. So avoid the synchronous call to md_update_sb and just set a flag so that the thread will do it. This can reduce the number of updates performed when lots of devices are being added or removed. Signed-off-by: NeilBrown Signed-off-by: Shaohua Li --- drivers/md/md.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) diff --git a/drivers/md/md.c b/drivers/md/md.c index 22c9efd..f389d8a 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -2599,8 +2599,10 @@ state_store(struct md_rdev *rdev, const char *buf, size_t len) if (err == 0) { md_kick_rdev_from_array(rdev); - if (mddev->pers) - md_update_sb(mddev, 1); + if (mddev->pers) { + set_bit(MD_CHANGE_DEVS, &mddev->flags); + md_wakeup_thread(mddev->thread); + } md_new_event(mddev); } } @@ -6175,7 +6177,11 @@ kick_rdev: md_cluster_ops->remove_disk(mddev, rdev); md_kick_rdev_from_array(rdev); - md_update_sb(mddev, 1); + set_bit(MD_CHANGE_DEVS, &mddev->flags); + if (mddev->thread) + md_wakeup_thread(mddev->thread); + else + md_update_sb(mddev, 1); md_new_event(mddev); return 0; @@ -6240,7 +6246,9 @@ static int hot_add_disk(struct mddev *mddev, dev_t dev) rdev->raid_disk = -1; - md_update_sb(mddev, 1); + set_bit(MD_CHANGE_DEVS, &mddev->flags); + if (!mddev->thread) + md_update_sb(mddev, 1); /* * Kick recovery, maybe this spare has to be added to the * array immediately. -- 2.7.4