linux-kernel - Re: [PATCH 1/3] slub: set a criteria for slub node partial adding

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Date:	Mon, 05 Dec 2011 10:21:04 +0800
From:	Shaohua Li <shaohua.li@...el.com>
To:	Christoph Lameter <cl@...ux.com>
Cc:	Eric Dumazet <eric.dumazet@...il.com>,
	"Shi, Alex" <alex.shi@...el.com>,
	"penberg@...nel.org" <penberg@...nel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-mm@...ck.org" <linux-mm@...ck.org>
Subject: Re: [PATCH 1/3] slub: set a criteria for slub node partial adding

On Sat, 2011-12-03 at 04:02 +0800, Christoph Lameter wrote:
> On Fri, 2 Dec 2011, Eric Dumazet wrote:
> 
> > netperf (loopback or ethernet) is a known stress test for slub, and your
> > patch removes code that might hurt netperf, but benefit real workload.
> >
> > Have you tried instead this far less intrusive solution ?
> >
> > if (tail == DEACTIVATE_TO_TAIL ||
> >     page->inuse > page->objects / 4)
> >          list_add_tail(&page->lru, &n->partial);
> > else
> >          list_add(&page->lru, &n->partial);
> 
> One could also move this logic to reside outside of the call to
> add_partial(). This is called mostly from __slab_free() so the logic could
> be put in there.
I'm wondering where the improvement comes from. The new added partial
page almost always has few free objects (the inuse < objects/4 isn't
popular I thought), that's why we add it to list tail.

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