linux-kernel - Re: [PATCH] mm: raise MemFree by reverting percpu_pagelist

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Message-ID: <4FACD00D.4060003@kernel.org>
Date:	Fri, 11 May 2012 17:38:37 +0900
From:	Minchan Kim <minchan@...nel.org>
To:	Sasha Levin <levinsasha928@...il.com>
CC:	Hugh Dickins <hughd@...gle.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Andrew Morton <akpm@...ux-foundation.org>, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mm: raise MemFree by reverting percpu_pagelist_fraction
 to 0

On 05/11/2012 05:30 PM, Sasha Levin wrote:

> On Fri, May 11, 2012 at 10:00 AM, Hugh Dickins <hughd@...gle.com> wrote:
>> Commit 93278814d359 "mm: fix division by 0 in percpu_pagelist_fraction()"
>> mistakenly initialized percpu_pagelist_fraction to the sysctl's minimum 8,
>> which leaves 1/8th of memory on percpu lists (on each cpu??); but most of
>> us expect it to be left unset at 0 (and it's not then used as a divisor).
> 
> I'm a bit confused about this, does it mean that once you set
> percpu_pagelist_fraction to a value above the minimum, you can no
> longer set it back to being 0?


Unfortunately, Yes. :(
It's rather awkward and need fix.


-- 
Kind regards,
Minchan Kim
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