From: Linwei Wang <wanix1988@gmail.com>
To: Aaron Lu <ziqianlu@bytedance.com>
Cc: Linwei Wang <wanix1988@gmail.com>, Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Juri Lelli <juri.lelli@redhat.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Steven Rostedt <rostedt@goodmis.org>,
Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
Valentin Schneider <vschneid@redhat.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] sched/fair: remove redundant se initialization in unthrottle_cfs_rq
Date: Wed, 12 Nov 2025 22:21:19 +0800 [thread overview]
Message-ID: <20251112142119.375184-1-wanix1988@gmail.com> (raw)
In-Reply-To: <CANCG0GdjAaXG5U=9etbC3qo5uY7fbpFTG_RqoKcgChVSrLOKWA@mail.gmail.com>
Hi Aaron,
Your commit 956dfda6a708 removes the duplicate assignment after the early
return, but still initializes 'se' at declaration:
struct sched_entity *se = cfs_rq->tg->se[cpu_of(rq)];
This initialization happens before the early return check at line 6036-6037,
so when runtime_remaining <= 0 causes an early return, the array access
is wasted.
My patch defers initialization until after the early return:
- struct sched_entity *se = cfs_rq->tg->se[cpu_of(rq)];
+ struct sched_entity *se;
...
+ se = cfs_rq->tg->se[cpu_of(rq)];
Your commit fixes the duplicate assignment; mine optimizes the early return
path. They're independent optimizations.
Should I rebase on top of 956dfda6a708?
Thanks.
prev parent reply other threads:[~2025-11-12 14:21 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-08 7:38 Linwei Wang
2025-11-11 7:40 ` Aaron Lu
2025-11-12 14:21 ` Linwei Wang [this message]
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