Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Ingo Molnar:
"A deadline scheduler warning/race fix, and a cfs_period_us quota
calculation workaround where the real fix looks too involved to merge
immediately"
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/deadline: Correctly handle active 0-lag timers
sched/fair: Limit sched_cfs_period_timer() loop to avoid hard lockup
+26
-2
+1
-2
kernel/sched/deadline.c
+1
-2
kernel/sched/deadline.c
···
252
252
if (dl_entity_is_special(dl_se))
253
253
return;
254
254
255
-
WARN_ON(hrtimer_active(&dl_se->inactive_timer));
256
255
WARN_ON(dl_se->dl_non_contending);
257
256
258
257
zerolag_time = dl_se->deadline -
···
268
269
* If the "0-lag time" already passed, decrease the active
269
270
* utilization now, instead of starting a timer
270
271
*/
271
-
if (zerolag_time < 0) {
272
+
if ((zerolag_time < 0) || hrtimer_active(&dl_se->inactive_timer)) {
272
273
if (dl_task(p))
273
274
sub_running_bw(dl_se, dl_rq);
274
275
if (!dl_task(p) || p->state == TASK_DEAD) {
+25
kernel/sched/fair.c
+25
kernel/sched/fair.c
···
4885
4885
return HRTIMER_NORESTART;
4886
4886
}
4887
4887
4888
+
extern const u64 max_cfs_quota_period;
4889
+
4888
4890
static enum hrtimer_restart sched_cfs_period_timer(struct hrtimer *timer)
4889
4891
{
4890
4892
struct cfs_bandwidth *cfs_b =
···
4894
4892
unsigned long flags;
4895
4893
int overrun;
4896
4894
int idle = 0;
4895
+
int count = 0;
4897
4896
4898
4897
raw_spin_lock_irqsave(&cfs_b->lock, flags);
4899
4898
for (;;) {
4900
4899
overrun = hrtimer_forward_now(timer, cfs_b->period);
4901
4900
if (!overrun)
4902
4901
break;
4902
+
4903
+
if (++count > 3) {
4904
+
u64 new, old = ktime_to_ns(cfs_b->period);
4905
+
4906
+
new = (old * 147) / 128; /* ~115% */
4907
+
new = min(new, max_cfs_quota_period);
4908
+
4909
+
cfs_b->period = ns_to_ktime(new);
4910
+
4911
+
/* since max is 1s, this is limited to 1e9^2, which fits in u64 */
4912
+
cfs_b->quota *= new;
4913
+
cfs_b->quota = div64_u64(cfs_b->quota, old);
4914
+
4915
+
pr_warn_ratelimited(
4916
+
"cfs_period_timer[cpu%d]: period too short, scaling up (new cfs_period_us %lld, cfs_quota_us = %lld)\n",
4917
+
smp_processor_id(),
4918
+
div_u64(new, NSEC_PER_USEC),
4919
+
div_u64(cfs_b->quota, NSEC_PER_USEC));
4920
+
4921
+
/* reset count so we don't come right back in here */
4922
+
count = 0;
4923
+
}
4903
4924
4904
4925
idle = do_sched_cfs_period_timer(cfs_b, overrun, flags);
4905
4926
}