From fa6fb5aab85f3e2d9cf017ec516a8c234402a7cd Mon Sep 17 00:00:00 2001 From: Shaohua Li Date: Mon, 27 Mar 2017 10:51:43 -0700 Subject: blk-throttle: ignore idle cgroup limit Last patch introduces a way to detect idle cgroup. We use it to make upgrade/downgrade decision. And the new algorithm can detect completely idle cgroup too, so we can delete the corresponding code. Signed-off-by: Shaohua Li Signed-off-by: Jens Axboe --- block/blk-throttle.c | 40 ++++++++++++++++++++++++++-------------- 1 file changed, 26 insertions(+), 14 deletions(-) (limited to 'block/blk-throttle.c') diff --git a/block/blk-throttle.c b/block/blk-throttle.c index f03e158ee1977..0ea8698b2b1f3 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -152,8 +152,6 @@ struct throtl_grp { unsigned long last_check_time; - unsigned long last_dispatch_time[2]; - /* When did we start a new slice */ unsigned long slice_start[2]; unsigned long slice_end[2]; @@ -508,8 +506,6 @@ static void throtl_pd_online(struct blkg_policy_data *pd) * Update has_rules[] after a new group is brought online. */ tg_update_has_rules(tg); - tg->last_dispatch_time[READ] = jiffies; - tg->last_dispatch_time[WRITE] = jiffies; } static void blk_throtl_update_limit_valid(struct throtl_data *td) @@ -1708,9 +1704,8 @@ static bool throtl_tg_can_upgrade(struct throtl_grp *tg) return true; if (time_after_eq(jiffies, - tg->last_dispatch_time[READ] + tg->td->throtl_slice) && - time_after_eq(jiffies, - tg->last_dispatch_time[WRITE] + tg->td->throtl_slice)) + tg_last_low_overflow_time(tg) + tg->td->throtl_slice) && + throtl_tg_is_idle(tg)) return true; return false; } @@ -1756,6 +1751,26 @@ static bool throtl_can_upgrade(struct throtl_data *td, return true; } +static void throtl_upgrade_check(struct throtl_grp *tg) +{ + unsigned long now = jiffies; + + if (tg->td->limit_index != LIMIT_LOW) + return; + + if (time_after(tg->last_check_time + tg->td->throtl_slice, now)) + return; + + tg->last_check_time = now; + + if (!time_after_eq(now, + __tg_last_low_overflow_time(tg) + tg->td->throtl_slice)) + return; + + if (throtl_can_upgrade(tg->td, NULL)) + throtl_upgrade_state(tg->td); +} + static void throtl_upgrade_state(struct throtl_data *td) { struct cgroup_subsys_state *pos_css; @@ -1797,18 +1812,15 @@ static bool throtl_tg_can_downgrade(struct throtl_grp *tg) struct throtl_data *td = tg->td; unsigned long now = jiffies; - if (time_after_eq(now, tg->last_dispatch_time[READ] + - td->throtl_slice) && - time_after_eq(now, tg->last_dispatch_time[WRITE] + - td->throtl_slice)) - return false; /* * If cgroup is below low limit, consider downgrade and throttle other * cgroups */ if (time_after_eq(now, td->low_upgrade_time + td->throtl_slice) && time_after_eq(now, tg_last_low_overflow_time(tg) + - td->throtl_slice)) + td->throtl_slice) && + (!throtl_tg_is_idle(tg) || + !list_empty(&tg_to_blkg(tg)->blkcg->css.children))) return true; return false; } @@ -1931,10 +1943,10 @@ bool blk_throtl_bio(struct request_queue *q, struct blkcg_gq *blkg, again: while (true) { - tg->last_dispatch_time[rw] = jiffies; if (tg->last_low_overflow_time[rw] == 0) tg->last_low_overflow_time[rw] = jiffies; throtl_downgrade_check(tg); + throtl_upgrade_check(tg); /* throtl is FIFO - if bios are already queued, should queue */ if (sq->nr_queued[rw]) break; -- cgit v1.2.3