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From: Peter Zijlstra <peterz@infradead.org>
To: Byungchul Park <byungchul.park@lge.com>
Cc: mingo@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] sched/fair: Fix update_min_vruntime() to get proper min_vruntime
Date: Tue, 6 Sep 2016 10:48:39 +0200	[thread overview]
Message-ID: <20160906084839.GG10153@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <1473138317-8789-1-git-send-email-byungchul.park@lge.com>

On Tue, Sep 06, 2016 at 02:05:17PM +0900, Byungchul Park wrote:
> From 295895be8befbab040d6054bb8186c03daabcedd Mon Sep 17 00:00:00 2001
> From: Byungchul Park <byungchul.park@lge.com>
> Date: Tue, 6 Sep 2016 12:22:26 +0900
> Subject: [PATCH] sched/fair: Fix update_min_vruntime() to get proper
>  min_vruntime
> 
> Commit 97a7142 'sched/fair: Make update_min_vruntime() more readable'
> introduces a bug that cfs_rq gets a wrong min_vruntime if
> !cfs_rq->rb_leftmost && cfs_rq->curr. This fixes it and makes it more
> readable and simple.

Urgh, I actually stared at that patch for quite a time and somehow
convinced myself it was good. I actually considered that scenario I
think.

/me thinks more..

Argh, I'm an idiot, you're right. By using min_vruntime() on
cfs_rq->curr we take the leftmost and fail to advance min_vruntime in
that case.

I'll ask Ingo to take the patch out.

  reply	other threads:[~2016-09-06  8:49 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-06  5:05 [PATCH] sched/fair: Fix update_min_vruntime() to get proper min_vruntime Byungchul Park
2016-09-06  8:48 ` Peter Zijlstra [this message]
2016-09-09  2:46   ` Byungchul Park

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