Date: Thu, 9 Apr 2009 09:22:36 +0200
From: Andi Kleen <andi@firstfloor.org>
To: Roland Dreier <rdreier@cisco.com>
Cc: Andi Kleen <andi@firstfloor.org>,
       Andrew Morton <akpm@linux-foundation.org>, linux-kernel@vger.kernel.org,
       linux-mm@kvack.org, x86@kernel.org
Subject: Re: [PATCH] [0/16] POISON: Intro
Message-ID: <20090409072236.GE14687@one.firstfloor.org>
References: <20090407509.382219156@firstfloor.org> <20090407221542.91cd3c42.akpm@linux-foundation.org> <20090408061539.GD17934@one.firstfloor.org> <adafxgj6old.fsf@cisco.com>
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On Wed, Apr 08, 2009 at 10:29:34AM -0700, Roland Dreier wrote:
>  > [1] I didn't consider that one high priority since production
>  > systems with long uptime shouldn't have much free memory.
> 
> Surely there are windows after a big job exits where lots of memory
> might be free.  Not sure how big those windows are in practice but it
> does seem if a process using 128GB exits then it might take a while
> before that memory all gets used again.

Yes, it's definitely something to be fixed at some point.
Basically just needs a new entry point into the page_alloc
buddy allocator to unfree a page. The more tricky part
is actually finding a good injector design for testing for it,
there's no natural race free way to get a free page.

-Andi
-- 
ak@linux.intel.com -- Speaking for myself only.
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