Re: [3.11 1/4] slub: Make cpu partial slab support configurable V2

[Joonsoo Kim <iamjoonsoo.kim@lge.com>]

On Thu, Jun 20, 2013 at 10:53:36AM +0800, Wanpeng Li wrote:
> On Thu, Jun 20, 2013 at 10:50:56AM +0900, Joonsoo Kim wrote:
> >On Wed, Jun 19, 2013 at 02:29:29PM +0000, Christoph Lameter wrote:
> >
> >
> >-----------------8<-----------------------------------------------
> >>From a3257adcff89fd89a7ecb26c1247eec511302807 Mon Sep 17 00:00:00 2001
> >From: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> >Date: Wed, 19 Jun 2013 14:05:52 +0900
> >Subject: [PATCH] slub: Make cpu partial slab support configurable
> >
> >cpu partial support can introduce level of indeterminism that is not
> >wanted in certain context (like a realtime kernel). Make it configurable.
> >
> >This patch is based on Christoph Lameter's
> >"slub: Make cpu partial slab support configurable V2".
> >
> 
> As you know, actually cpu_partial is the maximum number of objects kept 
> in the per cpu slab and cpu partial lists of a processor instead of 
> just the maximum number of objects kept in cpu partial lists of a
> processor. The allocation will always fallback to slow path if not 
> config SLUB_CPU_PARTIAL, whether it will lead to more latency?

No, the SLUB maintain a cpu slab even if s->cpu_partial is 0.
It is a violation of definition of cpu_partial as you pointed out, but,
current implementation do this way.

Thanks.

> 
> Regards,
> Wanpeng Li 
> 

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