This is a note to let you know that I've just added the patch titled
sched/fair: Keep load_avg and load_sum synced
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
sched-fair-keep-load_avg-and-load_sum-synced.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 7c7ad626d9a0ff0a36c1e2a3cfbbc6a13828d5eb Mon Sep 17 00:00:00 2001
From: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
Date: Thu, 27 May 2021 14:29:15 +0200
Subject: sched/fair: Keep load_avg and load_sum synced
From: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
commit 7c7ad626d9a0ff0a36c1e2a3cfbbc6a13828d5eb upstream.
when removing a cfs_rq from the list we only check _sum value so we must
ensure that _avg and _sum stay synced so load_sum can't be null whereas
load_avg is not after propagating load in the cgroup hierarchy.
Use load_avg to compute load_sum similarly to what is done for util_sum
and runnable_sum.
Fixes: 0e2d2aaaae52 ("sched/fair: Rewrite PELT migration propagation")
Reported-by: Odin Ugedal <odin@xxxxxxx>
Signed-off-by: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Reviewed-by: Odin Ugedal <odin@xxxxxxx>
Link: https://lkml.kernel.org/r/20210527122916.27683-2-vincent.guittot@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/sched/fair.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3501,10 +3501,9 @@ update_tg_cfs_runnable(struct cfs_rq *cf
static inline void
update_tg_cfs_load(struct cfs_rq *cfs_rq, struct sched_entity *se, struct cfs_rq *gcfs_rq)
{
- long delta_avg, running_sum, runnable_sum = gcfs_rq->prop_runnable_sum;
+ long delta, running_sum, runnable_sum = gcfs_rq->prop_runnable_sum;
unsigned long load_avg;
u64 load_sum = 0;
- s64 delta_sum;
u32 divider;
if (!runnable_sum)
@@ -3551,13 +3550,13 @@ update_tg_cfs_load(struct cfs_rq *cfs_rq
load_sum = (s64)se_weight(se) * runnable_sum;
load_avg = div_s64(load_sum, divider);
- delta_sum = load_sum - (s64)se_weight(se) * se->avg.load_sum;
- delta_avg = load_avg - se->avg.load_avg;
+ delta = load_avg - se->avg.load_avg;
se->avg.load_sum = runnable_sum;
se->avg.load_avg = load_avg;
- add_positive(&cfs_rq->avg.load_avg, delta_avg);
- add_positive(&cfs_rq->avg.load_sum, delta_sum);
+
+ add_positive(&cfs_rq->avg.load_avg, delta);
+ cfs_rq->avg.load_sum = cfs_rq->avg.load_avg * divider;
}
static inline void add_tg_cfs_propagate(struct cfs_rq *cfs_rq, long runnable_sum)
Patches currently in stable-queue which might be from vincent.guittot@xxxxxxxxxx are
queue-5.10/sched-fair-fix-util_est-util_avg_unchanged-handling.patch
queue-5.10/sched-fair-keep-load_avg-and-load_sum-synced.patch
queue-5.10/sched-fair-make-sure-to-update-tg-contrib-for-blocked-load.patch
