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authorHuaixin Chang <changhuaixin@linux.alibaba.com>2020-04-20 10:44:21 +0800
committerPeter Zijlstra <peterz@infradead.org>2020-04-30 20:14:40 +0200
commit5a6d6a6ccb5f48ca8cf7c6d64ff83fd9c7999390 (patch)
tree1f9d369362c55ed780292d621b35251f2db0cf0d /kernel/sched/fair.c
parent457d1f465778ccb5f14f7d7a62245e41d12a3804 (diff)
downloadlinux-5a6d6a6ccb5f48ca8cf7c6d64ff83fd9c7999390.tar.gz
sched/fair: Refill bandwidth before scaling
In order to prevent possible hardlockup of sched_cfs_period_timer() loop, loop count is introduced to denote whether to scale quota and period or not. However, scale is done between forwarding period timer and refilling cfs bandwidth runtime, which means that period timer is forwarded with old "period" while runtime is refilled with scaled "quota". Move do_sched_cfs_period_timer() before scaling to solve this. Fixes: 2e8e19226398 ("sched/fair: Limit sched_cfs_period_timer() loop to avoid hard lockup") Signed-off-by: Huaixin Chang <changhuaixin@linux.alibaba.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Ben Segall <bsegall@google.com> Reviewed-by: Phil Auld <pauld@redhat.com> Link: https://lkml.kernel.org/r/20200420024421.22442-3-changhuaixin@linux.alibaba.com
Diffstat (limited to 'kernel/sched/fair.c')
-rw-r--r--kernel/sched/fair.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index c0216ef33c0c..fac5b2f85247 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5159,6 +5159,8 @@ static enum hrtimer_restart sched_cfs_period_timer(struct hrtimer *timer)
if (!overrun)
break;
+ idle = do_sched_cfs_period_timer(cfs_b, overrun, flags);
+
if (++count > 3) {
u64 new, old = ktime_to_ns(cfs_b->period);
@@ -5188,8 +5190,6 @@ static enum hrtimer_restart sched_cfs_period_timer(struct hrtimer *timer)
/* reset count so we don't come right back in here */
count = 0;
}
-
- idle = do_sched_cfs_period_timer(cfs_b, overrun, flags);
}
if (idle)
cfs_b->period_active = 0;