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:
"Two fixes: a guest-cputime accounting fix, and a cgroup bandwidth
quota precision fix"
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/vtime: Fix guest/system mis-accounting on task switch
sched/fair: Scale bandwidth quota and period without losing quota/period ratio precision
+24
-16
+3
-3
kernel/sched/cputime.c
+3
-3
kernel/sched/cputime.c
···
740
740
741
741
write_seqcount_begin(&vtime->seqcount);
742
742
/* We might have scheduled out from guest path */
743
-
if (current->flags & PF_VCPU)
743
+
if (tsk->flags & PF_VCPU)
744
744
vtime_account_guest(tsk, vtime);
745
745
else
746
746
__vtime_account_system(tsk, vtime);
···
783
783
*/
784
784
write_seqcount_begin(&vtime->seqcount);
785
785
__vtime_account_system(tsk, vtime);
786
-
current->flags |= PF_VCPU;
786
+
tsk->flags |= PF_VCPU;
787
787
write_seqcount_end(&vtime->seqcount);
788
788
}
789
789
EXPORT_SYMBOL_GPL(vtime_guest_enter);
···
794
794
795
795
write_seqcount_begin(&vtime->seqcount);
796
796
vtime_account_guest(tsk, vtime);
797
-
current->flags &= ~PF_VCPU;
797
+
tsk->flags &= ~PF_VCPU;
798
798
write_seqcount_end(&vtime->seqcount);
799
799
}
800
800
EXPORT_SYMBOL_GPL(vtime_guest_exit);
+21
-13
kernel/sched/fair.c
+21
-13
kernel/sched/fair.c
···
4926
4926
if (++count > 3) {
4927
4927
u64 new, old = ktime_to_ns(cfs_b->period);
4928
4928
4929
-
new = (old * 147) / 128; /* ~115% */
4930
-
new = min(new, max_cfs_quota_period);
4929
+
/*
4930
+
* Grow period by a factor of 2 to avoid losing precision.
4931
+
* Precision loss in the quota/period ratio can cause __cfs_schedulable
4932
+
* to fail.
4933
+
*/
4934
+
new = old * 2;
4935
+
if (new < max_cfs_quota_period) {
4936
+
cfs_b->period = ns_to_ktime(new);
4937
+
cfs_b->quota *= 2;
4931
4938
4932
-
cfs_b->period = ns_to_ktime(new);
4933
-
4934
-
/* since max is 1s, this is limited to 1e9^2, which fits in u64 */
4935
-
cfs_b->quota *= new;
4936
-
cfs_b->quota = div64_u64(cfs_b->quota, old);
4937
-
4938
-
pr_warn_ratelimited(
4939
-
"cfs_period_timer[cpu%d]: period too short, scaling up (new cfs_period_us %lld, cfs_quota_us = %lld)\n",
4940
-
smp_processor_id(),
4941
-
div_u64(new, NSEC_PER_USEC),
4942
-
div_u64(cfs_b->quota, NSEC_PER_USEC));
4939
+
pr_warn_ratelimited(
4940
+
"cfs_period_timer[cpu%d]: period too short, scaling up (new cfs_period_us = %lld, cfs_quota_us = %lld)\n",
4941
+
smp_processor_id(),
4942
+
div_u64(new, NSEC_PER_USEC),
4943
+
div_u64(cfs_b->quota, NSEC_PER_USEC));
4944
+
} else {
4945
+
pr_warn_ratelimited(
4946
+
"cfs_period_timer[cpu%d]: period too short, but cannot scale up without losing precision (cfs_period_us = %lld, cfs_quota_us = %lld)\n",
4947
+
smp_processor_id(),
4948
+
div_u64(old, NSEC_PER_USEC),
4949
+
div_u64(cfs_b->quota, NSEC_PER_USEC));
4950
+
}
4943
4951
4944
4952
/* reset count so we don't come right back in here */
4945
4953
count = 0;