From: "Doug Smythies" <dsmythies@telus.net>
To: "'Vincent Guittot'" <vincent.guittot@linaro.org>
Cc: "'linux-kernel'" <linux-kernel@vger.kernel.org>,
"'open list:THERMAL'" <linux-pm@vger.kernel.org>,
"'Peter Zijlstra'" <peterz@infradead.org>,
"'Ingo Molnar'" <mingo@kernel.org>,
"'Linus Torvalds'" <torvalds@linux-foundation.org>,
"'Thomas Gleixner'" <tglx@linutronix.de>,
"'Sargun Dhillon'" <sargun@sargun.me>,
"'Tejun Heo'" <tj@kernel.org>,
"'Xie XiuQi'" <xiexiuqi@huawei.com>, <xiezhipeng1@huawei.com>,
"'Srinivas Pandruvada'" <srinivas.pandruvada@linux.intel.com>,
"'Rik van Riel'" <riel@surriel.com>
Subject: RE: [PATCH] Revert "sched/fair: Fix O(nr_cgroups) in the load balancing path"
Date: Wed, 30 Oct 2019 07:04:40 -0700 [thread overview]
Message-ID: <000001d58f2a$fc593200$f50b9600$@net> (raw)
In-Reply-To: <20191029160210.GA8343@linaro.org>
On 2019.10.29 09:02 Vincent Guittot wrote:
> Could you try the patch below ? It ensures that at least the root cfs rq stays
> in the list so each time update_blocked_averages is called, we will call update_cfs_rq_load_avg()
> for the root cfs_rq at least and even if everything already reach zero.
> This will ensure that cfs_rq_util_change is called even if nothing has
> changed.
>
> ---
> kernel/sched/fair.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 151c0b7..ac0a549 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -7552,6 +7552,8 @@ static inline void update_blocked_load_status(struct rq *rq, bool has_blocked) {
>
> static inline bool cfs_rq_is_decayed(struct cfs_rq *cfs_rq)
> {
> + struct rq *rq = rq_of(cfs_rq);
> +
> if (cfs_rq->load.weight)
> return false;
>
> @@ -7564,6 +7566,9 @@ static inline bool cfs_rq_is_decayed(struct cfs_rq *cfs_rq)
> if (cfs_rq->avg.runnable_load_sum)
> return false;
>
> + if (cfs_rq == &rq->cfs)
> + return false;
> +
> return true;
> }
>
> --
> 2.7.4
Yes, this patch works and solves the long time
between calls of the intel_pstate CPU frequency scaling
driver issue.
I see you sent a formal patch a few hours ago.
I'll try it and report back.
... Doug
next prev parent reply other threads:[~2019-10-30 14:04 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-25 15:55 [PATCH] Revert "sched/fair: Fix O(nr_cgroups) in the load balancing path" Doug Smythies
2019-10-25 16:51 ` Vincent Guittot
2019-10-26 6:59 ` Doug Smythies
2019-10-28 8:21 ` Vincent Guittot
2019-10-29 14:55 ` Doug Smythies
2019-10-29 15:36 ` Peter Zijlstra
2019-10-29 16:20 ` Vincent Guittot
2019-10-29 16:49 ` Peter Zijlstra
2019-10-29 17:00 ` Vincent Guittot
2019-10-29 17:09 ` Vincent Guittot
2019-10-29 16:02 ` Vincent Guittot
2019-10-30 14:04 ` Doug Smythies [this message]
2019-10-30 15:27 ` Vincent Guittot
2019-11-08 9:18 ` Vincent Guittot
2019-11-09 16:47 ` Doug Smythies
2019-11-10 15:13 ` Vincent Guittot
2019-10-29 19:34 ` Srinivas Pandruvada
2019-10-29 19:59 ` Srinivas Pandruvada
2019-10-30 15:54 ` Doug Smythies
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