On Sat, 15 Sep 2012 16:59:34 +0800 "Jianpeng Ma" <majianpeng@xxxxxxxxx> wrote:
> According commit 97e4f42d62badb0f9fbc27c013e89,it has 16 times to update
> checkpoint of sync/recovery in func md_do_sync().
> Because the the size of HDD became larger,the time of sync/recovery may
> taken long times.So the 1/16 of time maybe half hour or more.
> So it should add chance to update checkpoint.
> There are places which can update checkpoint in md_do_sync.
> 1: If call cond_resched and really sched
> 2: If curr_speed is larger than max_sync_spedd
> If above conditions are ok, we can try to update checkpoint.
>
> Signed-off-by: Jianpeng Ma <majianpeng@xxxxxxxxx>
> ---
> drivers/md/md.c | 16 +++++++++++++++-
> 1 file changed, 15 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index 3f6203a..c7993d6 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -7496,7 +7496,14 @@ void md_do_sync(struct mddev *mddev)
> * about not overloading the IO subsystem. (things like an
> * e2fsck being done on the RAID array should execute fast)
> */
> - cond_resched();
> + if (cond_resched())
> + if (!test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
> + mddev->curr_resync_completed != j &&
> + atomic_read(&mddev->recovery_active) == 0) {
> + mddev->curr_resync_completed = j;
> + set_bit(MD_CHANGE_CLEAN, &mddev->flags);
> + sysfs_notify(&mddev->kobj, NULL, "sync_completed");
> + }
>
> currspeed = ((unsigned long)(io_sectors-mddev->resync_mark_cnt))/2
> /((jiffies-mddev->resync_mark)/HZ +1) +1;
> @@ -7505,6 +7512,13 @@ void md_do_sync(struct mddev *mddev)
> if ((currspeed > speed_max(mddev)) ||
> !is_mddev_idle(mddev, 0)) {
> msleep(500);
> + if (!test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
> + mddev->curr_resync_completed != j &&
> + atomic_read(&mddev->recovery_active) == 0) {
> + mddev->curr_resync_completed = j;
> + set_bit(MD_CHANGE_CLEAN, &mddev->flags);
> + sysfs_notify(&mddev->kobj, NULL, "sync_completed");
> + }
> goto repeat;
> }
> }
I don't really like this. These two conditions seems rather arbitrary.
If we want to do a checkpoint more often, we should use some time based test
to do it.
What results do you get with this change? How often does a checkpoint happen
on a busy system? How often on an idle system?
A time-based update could be done in user-space. Just write 'idle' to
'sync_action' and it should do a checkpoint, then immediately restart from
where it left off.
NeilBrown
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