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From: Nick Piggin <nickpiggin@yahoo.com.au>
To: miaox@cn.fujitsu.com
Subject: Re: [PATCH] cpuset: fix allocating page cache/slab object on the unallowed node when memory spread is set
Date: Wed, 21 Jan 2009 19:30:26 +1100
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Cc: Ingo Molnar <mingo@elte.hu>, Andrew Morton <akpm@linux-foundation.org>,
       Paul Menage <menage@google.com>,
       "Linux-Kernel" <linux-kernel@vger.kernel.org>
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On Wednesday 21 January 2009 19:06:20 Miao Xie wrote:
> The task still allocated the page caches on old node after modifying its
> cpuset's mems when 'memory_spread_page' was set, it is caused by the old
> mem_allowed_list of the task, the current kernel doesn't updates it unless
> some function invokes cpuset_update_task_memory_state(), it is too late
> sometimes. We must update the mem_allowed_list of the tasks in time.
>
> Slab has the same problem.
>
> We fixes the bug by updating tasks' mem_allowed_list and spread flag after
> its cpuset's mems or spread flag is changed.

Thank you, this is a much better way to handle the problem, and keeps
those costly function calls out of fastpaths.

I don't know the cpuset code well enough to review it right now, but
the mm/ pieces thank you kindly for it :) Nice patch.

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