diff options
| author | Yu Kuai <yukuai3@huawei.com> | 2023-12-07 10:07:24 +0800 |
|---|---|---|
| committer | Song Liu <song@kernel.org> | 2023-12-07 10:19:47 -0800 |
| commit | b39113349de60e9b0bc97c2e129181b193c45054 (patch) | |
| tree | 16d09c2bb9b60da6a0afa203087edb9b62f81154 /drivers/md | |
| parent | f52f5c71f3d4bb0992800139d2f35cf9f6f6e0ee (diff) | |
md: split MD_RECOVERY_NEEDED out of mddev_resume
New mddev_resume() calls are added to synchronize IO with array
reconfiguration, however, this introduces a performance regression while
adding it in md_start_sync():
1) someone sets MD_RECOVERY_NEEDED first;
2) daemon thread grabs reconfig_mutex, then clears MD_RECOVERY_NEEDED and
queues a new sync work;
3) daemon thread releases reconfig_mutex;
4) in md_start_sync
a) check that there are spares that can be added/removed, then suspend
the array;
b) remove_and_add_spares may not be called, or called without really
add/remove spares;
c) resume the array, then set MD_RECOVERY_NEEDED again!
Loop between 2 - 4, then mddev_suspend() will be called quite often, for
consequence, normal IO will be quite slow.
Fix this problem by don't set MD_RECOVERY_NEEDED again in md_start_sync(),
hence the loop will be broken.
Fixes: bc08041b32ab ("md: suspend array in md_start_sync() if array need reconfiguration")
Suggested-by: Song Liu <song@kernel.org>
Reported-by: Janpieter Sollie <janpieter.sollie@edpnet.be>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218200
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20231207020724.2797445-1-yukuai1@huaweicloud.com
Diffstat (limited to 'drivers/md')
| -rw-r--r-- | drivers/md/md.c | 30 |
1 files changed, 26 insertions, 4 deletions
diff --git a/drivers/md/md.c b/drivers/md/md.c index bc9d67af1961..b066abbffd10 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -490,7 +490,7 @@ int mddev_suspend(struct mddev *mddev, bool interruptible) } EXPORT_SYMBOL_GPL(mddev_suspend); -void mddev_resume(struct mddev *mddev) +static void __mddev_resume(struct mddev *mddev, bool recovery_needed) { lockdep_assert_not_held(&mddev->reconfig_mutex); @@ -507,12 +507,18 @@ void mddev_resume(struct mddev *mddev) percpu_ref_resurrect(&mddev->active_io); wake_up(&mddev->sb_wait); - set_bit(MD_RECOVERY_NEEDED, &mddev->recovery); + if (recovery_needed) + set_bit(MD_RECOVERY_NEEDED, &mddev->recovery); md_wakeup_thread(mddev->thread); md_wakeup_thread(mddev->sync_thread); /* possibly kick off a reshape */ mutex_unlock(&mddev->suspend_mutex); } + +void mddev_resume(struct mddev *mddev) +{ + return __mddev_resume(mddev, true); +} EXPORT_SYMBOL_GPL(mddev_resume); /* @@ -9389,7 +9395,15 @@ static void md_start_sync(struct work_struct *ws) goto not_running; } - suspend ? mddev_unlock_and_resume(mddev) : mddev_unlock(mddev); + mddev_unlock(mddev); + /* + * md_start_sync was triggered by MD_RECOVERY_NEEDED, so we should + * not set it again. Otherwise, we may cause issue like this one: + * https://bugzilla.kernel.org/show_bug.cgi?id=218200 + * Therefore, use __mddev_resume(mddev, false). + */ + if (suspend) + __mddev_resume(mddev, false); md_wakeup_thread(mddev->sync_thread); sysfs_notify_dirent_safe(mddev->sysfs_action); md_new_event(); @@ -9401,7 +9415,15 @@ not_running: clear_bit(MD_RECOVERY_REQUESTED, &mddev->recovery); clear_bit(MD_RECOVERY_CHECK, &mddev->recovery); clear_bit(MD_RECOVERY_RUNNING, &mddev->recovery); - suspend ? mddev_unlock_and_resume(mddev) : mddev_unlock(mddev); + mddev_unlock(mddev); + /* + * md_start_sync was triggered by MD_RECOVERY_NEEDED, so we should + * not set it again. Otherwise, we may cause issue like this one: + * https://bugzilla.kernel.org/show_bug.cgi?id=218200 + * Therefore, use __mddev_resume(mddev, false). + */ + if (suspend) + __mddev_resume(mddev, false); wake_up(&resync_wait); if (test_and_clear_bit(MD_RECOVERY_RECOVER, &mddev->recovery) && |