linux-kernel - Re: [RFC PATCH 2/2] sched: Remove SD_WAKE_AFFINE flag and replace it with SD_BALANCE

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Date:	Tue, 31 May 2016 09:34:19 +0800
From:	Yuyang Du <yuyang.du@...el.com>
To:	Peter Zijlstra <peterz@...radead.org>
Cc:	mingo@...nel.org, linux-kernel@...r.kernel.org,
	umgwanakikbuti@...il.com, bsegall@...gle.com, pjt@...gle.com,
	morten.rasmussen@....com, vincent.guittot@...aro.org,
	dietmar.eggemann@....com
Subject: Re: [RFC PATCH 2/2] sched: Remove SD_WAKE_AFFINE flag and replace it
 with SD_BALANCE_WAKE

On Tue, May 31, 2016 at 11:23:14AM +0200, Peter Zijlstra wrote:
> On Tue, May 31, 2016 at 09:11:38AM +0800, Yuyang Du wrote:
> > SD_BALANCE_{FORK|EXEC|WAKE} flags are for select_task_rq() to select a
> > CPU to run a new task or a waking task. SD_WAKE_AFFINE is a flag to
> > try selecting the waker CPU to run the waking task.
> > 
> > SD_BALANCE_WAKE is not a sched_domain flag, but SD_WAKE_AFFINE is.
> 
> No, SD_BALANCE_{FORK,EXEC,WAKE} are very much sched_domain flags.
> 
> They indicate how wide we should look to place tasks on these events.

With this patch, they are, and in particular SD_BALANCE_WAKE is.

SD_WAKE_AFFINE is just a particular CPU candidate in SD_BALANCE_WAKE.