From: Matt Mackall <mpm@selenic.com>
To: Christoph Lameter <clameter@sgi.com>
Cc: akpm@osdl.org, Christoph Hellwig <hch@infradead.org>,
Arjan van de Ven <arjan@infradead.org>,
Nigel Cunningham <nigel@nigel.suspend2.net>,
"Martin J. Bligh" <mbligh@mbligh.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Nick Piggin <nickpiggin@yahoo.com.au>,
linux-mm@kvack.org, Rik van Riel <riel@redhat.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Subject: Re: [PATCH 2/7] Add PageMlocked() page state bit and lru infrastructure
Date: Wed, 14 Feb 2007 20:09:16 -0600 [thread overview]
Message-ID: <20070215020916.GS10108@waste.org> (raw)
In-Reply-To: <20070215012459.5343.72021.sendpatchset@schroedinger.engr.sgi.com>
On Wed, Feb 14, 2007 at 05:24:59PM -0800, Christoph Lameter wrote:
> Add PageMlocked() infrastructure
>
> This adds a new PG_mlocked to mark pages that were taken off the LRU
> because they have a reference from a VM_LOCKED vma.
>
> (Yes, we still have 4 free page flag bits.... BITS_PER_LONG-FLAGS_RESERVED =
> 32 - 9 = 23 page flags).
>
> Also add pagevec handling for returning mlocked pages to the LRU.
>
> Signed-off-by: Christoph Lameter <clameter@sgi.com>
>
> Index: linux-2.6.20/include/linux/page-flags.h
> ===================================================================
> --- linux-2.6.20.orig/include/linux/page-flags.h 2007-02-14 15:47:13.000000000 -0800
> +++ linux-2.6.20/include/linux/page-flags.h 2007-02-14 16:00:40.000000000 -0800
> @@ -91,6 +91,7 @@
> #define PG_nosave_free 18 /* Used for system suspend/resume */
> #define PG_buddy 19 /* Page is free, on buddy lists */
>
> +#define PG_mlocked 20 /* Page is mlocked */
I think we should be much more precise in documenting the semantics of
these bits. This particular comment is imprecise enough to be
incorrect. This bit being set indicates that we saw that it was
mlocked at some point in the past, not any guarantee that it's mlocked
now. And the same for the converse.
--
Mathematics is the supreme nostalgia of our time.
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next prev parent reply other threads:[~2007-02-15 2:09 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-02-15 1:24 [PATCH 0/7] Move mlocked pages off the LRU and track them V1 Christoph Lameter
2007-02-15 1:24 ` [PATCH 1/7] Make try_to_unmap return a special exit code Christoph Lameter
2007-02-15 1:24 ` [PATCH 2/7] Add PageMlocked() page state bit and lru infrastructure Christoph Lameter
2007-02-15 2:09 ` Matt Mackall [this message]
2007-02-15 2:30 ` Christoph Lameter
2007-02-15 14:51 ` Matt Mackall
2007-02-15 15:24 ` Christoph Lameter
2007-02-15 15:47 ` Martin J. Bligh
2007-02-15 16:05 ` Christoph Lameter
2007-02-15 1:25 ` [PATCH 3/7] Add NR_MLOCK ZVC Christoph Lameter
2007-02-15 1:25 ` [PATCH 4/7] Logic to move mlocked pages Christoph Lameter
2007-02-15 5:33 ` Andrew Morton
2007-02-15 15:19 ` Christoph Lameter
2007-02-15 5:39 ` Andrew Morton
2007-02-15 15:21 ` Christoph Lameter
2007-02-15 1:25 ` [PATCH 5/7] Consolidate new anonymous page code paths Christoph Lameter
2007-02-15 1:25 ` [PATCH 6/7] Avoid putting new mlocked anonymous pages on LRU Christoph Lameter
2007-02-15 1:25 ` [PATCH 7/7] Opportunistically move mlocked pages off the LRU Christoph Lameter
2007-02-15 4:39 ` KAMEZAWA Hiroyuki
2007-02-15 15:15 ` Christoph Lameter
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