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blk-throttle: ignore idle cgroup limit

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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 <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Shaohua Li 2017-03-27 10:51:43 -07:00 • committed by Jens Axboe
parent ada75b6e5b
commit fa6fb5aab8
1 changed files with 26 additions and 14 deletions
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40
block/blk-throttle.c
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@ -152,8 +152,6 @@ struct throtl_grp {
unsigned long last_check_time; unsigned long last_check_time;
unsigned long last_dispatch_time[2];
/* When did we start a new slice */ /* When did we start a new slice */
unsigned long slice_start[2]; unsigned long slice_start[2];
unsigned long slice_end[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. * Update has_rules[] after a new group is brought online.
*/ */
tg_update_has_rules(tg); 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) 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; return true;
if (time_after_eq(jiffies, if (time_after_eq(jiffies,
tg->last_dispatch_time[READ] + tg->td->throtl_slice) && tg_last_low_overflow_time(tg) + tg->td->throtl_slice) &&
time_after_eq(jiffies, throtl_tg_is_idle(tg))
tg->last_dispatch_time[WRITE] + tg->td->throtl_slice))
return true; return true;
return false; return false;
} }
@ -1756,6 +1751,26 @@ static bool throtl_can_upgrade(struct throtl_data *td,
return true; 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) static void throtl_upgrade_state(struct throtl_data *td)
{ {
struct cgroup_subsys_state *pos_css; 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; struct throtl_data *td = tg->td;
unsigned long now = jiffies; 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 * If cgroup is below low limit, consider downgrade and throttle other
* cgroups * cgroups
*/ */
if (time_after_eq(now, td->low_upgrade_time + td->throtl_slice) && if (time_after_eq(now, td->low_upgrade_time + td->throtl_slice) &&
time_after_eq(now, tg_last_low_overflow_time(tg) + 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 true;
return false; return false;
} }
@ -1931,10 +1943,10 @@ bool blk_throtl_bio(struct request_queue *q, struct blkcg_gq *blkg,
again: again:
while (true) { while (true) {
tg->last_dispatch_time[rw] = jiffies;
if (tg->last_low_overflow_time[rw] == 0) if (tg->last_low_overflow_time[rw] == 0)
tg->last_low_overflow_time[rw] = jiffies; tg->last_low_overflow_time[rw] = jiffies;
throtl_downgrade_check(tg); throtl_downgrade_check(tg);
throtl_upgrade_check(tg);
/* throtl is FIFO - if bios are already queued, should queue */ /* throtl is FIFO - if bios are already queued, should queue */
if (sq->nr_queued[rw]) if (sq->nr_queued[rw])
break; break;