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From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
To: a.p.zijlstra@chello.nl
Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org,
	efault@gmx.de, mingo@elte.hu
Subject: Re: [PATCH] cpumask: convert cpumask_of_cpu() with cpumask_of()
Date: Mon, 30 May 2011 10:40:07 +0900	[thread overview]
Message-ID: <4DE2F577.3000105@jp.fujitsu.com> (raw)
In-Reply-To: <1306442327.2497.108.camel@laptop>

>> The trick is,
>>  - Typical linux userland applications don't use mempolicy and/or cpusets
>>    API at all.
>>  - Then, 99.99% thread's  tsk->cpus_alloed have cpu_all_mask.
>>  - cpu_all_mask case, every thread can share the same bitmap. It may help to
>>    reduce L1 cache miss in scheduler.
>>
>> What do you think? 
> 
> Nice!
> 
> If you finish the first patch (sort the TODOs) I'll take it.

Yeah, now I'm submitting a lot of cpumask cleanup patches to various arch and
subsystems. So, I expect I can finish this work in June.

> I'm unsure about the PF_THREAD_UNBOUND thing though, then again, the
> alternative is adding another struct cpumask * and have that point to
> the shared mask or the private mask.

Ahhh, I'm sorry. My explanation was bad. PF_THREAD_UNBOUND is not my point.
It's only concept proof patch, not for submitting. yes, I did cheat for getting
number easily. I think the good way is probably to add another cpumask* and
implement COW shared mask. but I'm ok other way too.


> But yeah, looks quite feasible.

Thank you to pay attention my patch!


      reply	other threads:[~2011-05-30  1:40 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-04-25  9:41 [PATCH] cpumask: convert cpumask_of_cpu() with cpumask_of() KOSAKI Motohiro
2011-04-26 10:42 ` Peter Zijlstra
2011-04-26 11:33   ` KOSAKI Motohiro
2011-04-27 10:32     ` KOSAKI Motohiro
2011-05-26 20:38       ` Peter Zijlstra
2011-05-30  1:40         ` KOSAKI Motohiro [this message]

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