From: Peter Zijlstra <peterz@infradead.org>
To: Mel Gorman <mgorman@techsingularity.net>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>,
bristot@redhat.com, bsegall@google.com, dietmar.eggemann@arm.com,
joshdon@google.com, juri.lelli@redhat.com, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org,
linux@rasmusvillemoes.dk, mgorman@suse.de, mingo@kernel.org,
rostedt@goodmis.org, valentin.schneider@arm.com,
vincent.guittot@linaro.org
Subject: Re: [PATCH 1/1] sched/fair: improve yield_to vs fairness
Date: Tue, 27 Jul 2021 15:33:00 +0200 [thread overview]
Message-ID: <YQALDHw7Cr+vbeqN@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20210723093523.GX3809@techsingularity.net>
On Fri, Jul 23, 2021 at 10:35:23AM +0100, Mel Gorman wrote:
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 44c452072a1b..ddc0212d520f 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -4522,7 +4522,8 @@ pick_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *curr)
> se = second;
> }
>
> - if (cfs_rq->next && wakeup_preempt_entity(cfs_rq->next, left) < 1) {
> + if (cfs_rq->next &&
> + (cfs_rq->skip == left || wakeup_preempt_entity(cfs_rq->next, left) < 1)) {
> /*
> * Someone really wants this to run. If it's not unfair, run it.
> */
With a little more context this function reads like:
se = left;
if (cfs_rq->skip && cfs_rq->skip == se) {
...
+ if (cfs_rq->next && (cfs_rq->skip == left || ...))
If '...' doesn't change @left (afaict it doesn't), then your change (+)
is equivalent to '&& true', or am I reading things wrong?
next prev parent reply other threads:[~2021-07-27 13:39 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20210412102001.287610138@infradead.org>
2021-04-27 14:59 ` sched: Move SCHED_DEBUG sysctl to debugfs Christian Borntraeger
2021-04-27 15:09 ` Steven Rostedt
2021-04-27 15:17 ` Christian Borntraeger
2021-04-28 8:47 ` Peter Zijlstra
2021-04-28 8:46 ` Peter Zijlstra
2021-04-28 8:54 ` Christian Borntraeger
2021-04-28 8:58 ` Christian Borntraeger
2021-04-28 9:25 ` Peter Zijlstra
2021-04-28 9:31 ` Christian Borntraeger
2021-04-28 9:42 ` Christian Borntraeger
2021-04-28 12:38 ` Peter Zijlstra
2021-04-28 14:49 ` Christian Borntraeger
2021-07-07 12:34 ` [PATCH 0/1] Improve yield (was: sched: Move SCHED_DEBUG sysctl to debugfs) Christian Borntraeger
2021-07-07 12:34 ` [PATCH 1/1] sched/fair: improve yield_to vs fairness Christian Borntraeger
2021-07-07 18:07 ` kernel test robot
2021-07-23 9:35 ` Mel Gorman
2021-07-23 12:36 ` Christian Borntraeger
2021-07-23 16:21 ` Mel Gorman
2021-07-26 18:41 ` Christian Borntraeger
2021-07-26 19:32 ` Mel Gorman
2021-07-27 6:59 ` Christian Borntraeger
2021-07-27 18:57 ` Benjamin Segall
2021-07-28 16:23 ` Christian Borntraeger
2021-08-10 8:49 ` Vincent Guittot
2021-07-27 13:29 ` Peter Zijlstra
2021-07-27 13:33 ` Peter Zijlstra [this message]
2021-07-27 14:31 ` Mel Gorman
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