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From: Andrea Arcangeli <aarcange@redhat.com>
To: Nai Xia <nai.xia@gmail.com>
Cc: Hugh Dickins <hughd@google.com>, Mel Gorman <mgorman@suse.de>,
	Pawel Sikora <pluto@agmk.net>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-mm@kvack.org, jpiszcz@lucidpixels.com, arekm@pld-linux.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mremap: skip page table lookup for non-faulted anonymous VMAs
Date: Mon, 7 Nov 2011 16:32:20 +0100	[thread overview]
Message-ID: <20111107153220.GD3249@redhat.com> (raw)
In-Reply-To: <201111071221.35403.nai.xia@gmail.com>

On Mon, Nov 07, 2011 at 12:21:35PM +0800, Nai Xia wrote:
> If an anonymous vma has not yet been faulted, move_page_tables() in move_vma()
> is not necessary for it.

I actually thought of adding that (in fact fork has it and it's more
likely to be beneficial for fork than for mremap I suspect), but this
adds a branch to the fast path for a case that shouldn't normally
materialize. So I don't think it's worth adding it as I expect it to
add overhead in average.

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  reply	other threads:[~2011-11-07 15:32 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-11-07  4:21 Nai Xia
2011-11-07 15:32 ` Andrea Arcangeli [this message]
2011-11-07 16:13   ` Nai Xia

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