From: Andrew Morton <akpm@linux-foundation.org>
To: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Christoph Lameter <cl@linux.com>,
liu.hailong6@zte.com.cn, Pekka Enberg <penberg@kernel.org>,
linux-mm@kvack.org, jiang.xuexin@zte.com.cn,
David Rientjes <rientjes@google.com>
Subject: Re: slab:Fix the unexpected index mapping result of kmalloc_size(INDEX_NODE + 1)
Date: Fri, 4 Sep 2015 13:29:02 -0700 [thread overview]
Message-ID: <20150904132902.5d62a09077435d742d6f2f1b@linux-foundation.org> (raw)
In-Reply-To: <20150807015609.GB15802@js1304-P5Q-DELUXE>
On Fri, 7 Aug 2015 10:56:09 +0900 Joonsoo Kim <iamjoonsoo.kim@lge.com> wrote:
> On Fri, Jul 31, 2015 at 08:57:35AM -0500, Christoph Lameter wrote:
> > On Fri, 31 Jul 2015, Joonsoo Kim wrote:
> >
> > > I don't think that this fix is right.
> > > Just "kmalloc_size(INDEX_NODE) * 2" looks insane because it means 192 * 2
> > > = 384 on his platform. Why we need to check size is larger than 384?
> >
> > Its an arbitrary boundary. Making it large ensures that the smaller caches
> > stay operational and do not fall back to page sized allocations.
>
> If it is an arbitrary boundary, it would be better to use static value
> such as "256" rather than kmalloc_size(INDEX_NODE) * 2.
> Value of kmalloc_size(INDEX_NODE) * 2 can be different in some archs
> and it is difficult to manage such variation. It would cause this kinds of
> bug again. I recommand following change. How about it?
>
> - if (size >= kmalloc_size(INDEX_NODE + 1)
> + if (!slab_early_init &&
> + size >= kmalloc_size(INDEX_NODE) &&
> + size >= 256
>
Guys, can we please finish this off? afaict Jianxuexin's original
patch is considered undesirable, but his machine is still going BUG.
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next prev parent reply other threads:[~2015-09-04 20:29 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-09 5:56 liu.hailong6
2015-07-29 22:28 ` Andrew Morton
2015-07-30 16:29 ` Christoph Lameter
2015-07-31 0:18 ` Joonsoo Kim
2015-07-31 13:57 ` Christoph Lameter
2015-08-07 1:56 ` Joonsoo Kim
2015-09-04 20:29 ` Andrew Morton [this message]
2015-09-07 5:38 ` Joonsoo Kim
2015-09-08 17:49 ` Christoph Lameter
2015-09-11 14:32 ` Joonsoo Kim
2015-09-11 14:49 ` Christoph Lameter
-- strict thread matches above, loose matches on Subject: below --
2015-07-09 3:35 liu.hailong6
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