| Message ID | 40b42ff504ad8f54251ca4b8c088f217410aa791.1462923578.git.shli@fb.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
diff --git a/block/blk-throttle.c b/block/blk-throttle.c index 0aed049..a5f3435 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -632,6 +632,9 @@ static void throtl_dequeue_tg(struct throtl_grp *tg) static void throtl_schedule_pending_timer(struct throtl_service_queue *sq, unsigned long expires) { + unsigned long max_expire = jiffies + 8 * cg_check_time; + if (time_after(expires, max_expire)) + expires = max_expire; mod_timer(&sq->pending_timer, expires); throtl_log(sq, "schedule timer. delay=%lu jiffies=%lu", expires - jiffies, jiffies);
cgroup could be throttled to a limit but when other cgroups are idle, queue enters a higher state and so the group should be throttled to a higher limit. It's possible the cgroup is sleeping because of throttle and other cgroups don't dispatch IO any more. In this case, nobody can trigger current downgrade/upgrade logic. To fix this issue, we could either set up a timer to wakeup the cgroup if other cgroups are idle or make sure this cgroup doesn't sleep too long. Setting up a timer means we must change the timer very frequently. This patch chooses the latter. Making cgroup sleep time not too big wouldn't change cgroup bps/iops, but could make it wakeup more frequently, which isn't a big issue because cg_check_time * 8 is already quite big. Signed-off-by: Shaohua Li <shli@fb.com> --- block/blk-throttle.c | 3 +++ 1 file changed, 3 insertions(+)