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From: Mel Gorman <mgorman@suse.de>
To: Alex Shi <alex.shi@intel.com>
Cc: cl@linux.com, davem@davemloft.net, a.p.zijlstra@chello.nl,
	akpm@linux-foundation.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: correct page->pfmemalloc to fix deactivate_slab regression
Date: Mon, 13 Aug 2012 13:29:48 +0100	[thread overview]
Message-ID: <20120813122948.GF4177@suse.de> (raw)
In-Reply-To: <1344860075-31752-1-git-send-email-alex.shi@intel.com>

On Mon, Aug 13, 2012 at 08:14:35PM +0800, Alex Shi wrote:
> commit cfd19c5a9ec (mm: only set page->pfmemalloc when
> ALLOC_NO_WATERMARKS was used) try to narrow down page->pfmemalloc
> setting, but it missed some places the pfmemalloc should be set.
> 
> So, in __slab_alloc, the unalignment pfmemalloc and ALLOC_NO_WATERMARKS
> cause incorrect deactivate_slab() on our core2 server:
> 
>     64.73%           fio  [kernel.kallsyms]     [k] _raw_spin_lock
>                      |
>                      --- _raw_spin_lock
>                         |
>                         |---0.34%-- deactivate_slab
>                         |          __slab_alloc
>                         |          kmem_cache_alloc
>                         |          |
> 
> That causes our fio sync write performance has 40% regression.
> 
> This patch move the checking in get_page_from_freelist, that resolved
> this issue.
> 
> Signed-off-by: Alex Shi <alex.shi@intel.com>

Acked-by: Mel Gorman <mgorman@suse.de>

-- 
Mel Gorman
SUSE Labs

      reply	other threads:[~2012-08-13 12:29 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-08-13 12:14 Alex Shi
2012-08-13 12:29 ` Mel Gorman [this message]

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