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Date: Fri, 8 Jan 2010 09:23:33 +0900
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Subject: Re: [RFC][PATCH 6/8] mm: handle_speculative_fault()
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To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>, Christoph Lameter <cl@linux-foundation.org>, Arjan van de Ven <arjan@infradead.org>, "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, "linux-mm@kvack.org" <linux-mm@kvack.org>, "minchan.kim@gmail.com" <minchan.kim@gmail.com>, "hugh.dickins" <hugh.dickins@tiscali.co.uk>, Nick Piggin <nickpiggin@yahoo.com.au>, Ingo Molnar <mingo@elte.hu>
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On Thu, 7 Jan 2010 14:33:50 -0800 (PST)
Linus Torvalds <torvalds@linux-foundation.org> wrote:

> 
> 
> On Thu, 7 Jan 2010, Peter Zijlstra wrote:
> >
> > I haven't yet looked at the patch, but isn't expand_stack() kinda like
> > what you want? That serializes using anon_vma_lock().
> 
> Yeah, that sounds like the right thing to do.  It is the same operation, 
> after all (and has the same effects, especially for the special case of 
> upwards-growing stacks).
> 
> So basically the idea is to extend that stack expansion to brk(), and 
> possibly mmap() in general.
> 
Hmm, do_brk() sometimes unmap conflicting mapping. Isn't it be a problem ?
Stack expansion just fails and SEGV if it hit with other mmaps....

Thanks,
-Kame





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