From: Johannes Weiner <hannes@cmpxchg.org>
To: Simon Jeons <simon.jeons@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Rik van Riel <riel@redhat.com>, Michal Hocko <mhocko@suse.cz>,
Mel Gorman <mgorman@suse.de>, Hugh Dickins <hughd@google.com>,
Satoru Moriya <satoru.moriya@hds.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [patch 7/7] mm: reduce rmap overhead for ex-KSM page copies created on swap faults
Date: Wed, 19 Dec 2012 12:58:11 -0500 [thread overview]
Message-ID: <20121219175811.GD7147@cmpxchg.org> (raw)
In-Reply-To: <1355900479.1381.1.camel@kernel-VirtualBox>
On Wed, Dec 19, 2012 at 02:01:19AM -0500, Simon Jeons wrote:
> On Mon, 2012-12-17 at 13:12 -0500, Johannes Weiner wrote:
> > When ex-KSM pages are faulted from swap cache, the fault handler is
> > not capable of re-establishing anon_vma-spanning KSM pages. In this
> > case, a copy of the page is created instead, just like during a COW
> > break.
> >
> > These freshly made copies are known to be exclusive to the faulting
> > VMA and there is no reason to go look for this page in parent and
> > sibling processes during rmap operations.
> >
> > Use page_add_new_anon_rmap() for these copies. This also puts them on
> > the proper LRU lists and marks them SwapBacked, so we can get rid of
> > doing this ad-hoc in the KSM copy code.
>
> Is it just a code cleanup instead of reduce rmap overhead?
Both.
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prev parent reply other threads:[~2012-12-19 17:59 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-17 18:12 [patch 0/8] page reclaim bits v2 Johannes Weiner
2012-12-17 18:12 ` [patch 1/7] mm: memcg: only evict file pages when we have plenty Johannes Weiner
2012-12-17 18:15 ` Rik van Riel
2012-12-18 9:56 ` Mel Gorman
2012-12-17 18:12 ` [patch 2/7] mm: vmscan: save work scanning (almost) empty LRU lists Johannes Weiner
2012-12-19 23:59 ` Andrew Morton
2012-12-20 13:55 ` Michal Hocko
2012-12-21 3:02 ` Johannes Weiner
2012-12-17 18:12 ` [patch 3/7] mm: vmscan: clarify how swappiness, highest priority, memcg interact Johannes Weiner
2012-12-17 18:16 ` Rik van Riel
2012-12-17 19:37 ` Satoru Moriya
2012-12-17 20:05 ` Michal Hocko
2012-12-18 10:04 ` Mel Gorman
2012-12-18 15:16 ` Satoru Moriya
2012-12-17 18:12 ` [patch 4/7] mm: vmscan: improve comment on low-page cache handling Johannes Weiner
2012-12-17 18:12 ` [patch 5/7] mm: vmscan: clean up get_scan_count() Johannes Weiner
2012-12-20 0:08 ` Andrew Morton
2012-12-21 2:49 ` Johannes Weiner
2012-12-17 18:12 ` [patch 6/7] mm: vmscan: compaction works against zones, not lruvecs Johannes Weiner
2012-12-17 18:12 ` [patch 7/7] mm: reduce rmap overhead for ex-KSM page copies created on swap faults Johannes Weiner
2012-12-17 22:42 ` Hugh Dickins
2012-12-19 7:01 ` Simon Jeons
2012-12-19 17:58 ` Johannes Weiner [this message]
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