From: Andrew Morton <akpm@linux-foundation.org>
To: Mel Gorman <mgorman@suse.de>
Cc: Alexey Lyahkov <alexey.lyashkov@gmail.com>,
Andrew Perepechko <anserper@ya.ru>,
Robin Dong <sanbai@taobao.com>, Theodore Tso <tytso@mit.edu>,
Hugh Dickins <hughd@google.com>, Rik van Riel <riel@redhat.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Bernd Schubert <bernd.schubert@fastmail.fm>,
David Howells <dhowells@redhat.com>,
Trond Myklebust <Trond.Myklebust@netapp.com>,
Linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Linux-ext4 <linux-ext4@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Linux-mm <linux-mm@kvack.org>
Subject: Re: [PATCH 2/4] mm: pagevec: Defer deciding what LRU to add a page to until pagevec drain time
Date: Wed, 15 May 2013 15:53:30 -0700 [thread overview]
Message-ID: <20130515155330.35036978515a6d8e0fe98feb@linux-foundation.org> (raw)
In-Reply-To: <1368440482-27909-3-git-send-email-mgorman@suse.de>
On Mon, 13 May 2013 11:21:20 +0100 Mel Gorman <mgorman@suse.de> wrote:
> mark_page_accessed cannot activate an inactive page that is located on
> an inactive LRU pagevec. Hints from filesystems may be ignored as a
> result. In preparation for fixing that problem, this patch removes the
> per-LRU pagevecs and leaves just one pagevec. The final LRU the page is
> added to is deferred until the pagevec is drained.
>
> This means that fewer pagevecs are available and potentially there is
> greater contention on the LRU lock. However, this only applies in the case
> where there is an almost perfect mix of file, anon, active and inactive
> pages being added to the LRU. In practice I expect that we are adding
> stream of pages of a particular time and that the changes in contention
> will barely be measurable.
>
> ...
>
> index c612a6a..0911579 100644
> --- a/mm/swap.c
> +++ b/mm/swap.c
> @@ -39,7 +39,7 @@
> /* How many pages do we try to swap or page in/out together? */
> int page_cluster;
>
> -static DEFINE_PER_CPU(struct pagevec[NR_LRU_LISTS], lru_add_pvecs);
> +static DEFINE_PER_CPU(struct pagevec, lru_add_pvec);
> static DEFINE_PER_CPU(struct pagevec, lru_rotate_pvecs);
> static DEFINE_PER_CPU(struct pagevec, lru_deactivate_pvecs);
>
> @@ -460,13 +460,18 @@ EXPORT_SYMBOL(mark_page_accessed);
> */
The comment preceding __lru_cache_add() needs an update.
> void __lru_cache_add(struct page *page, enum lru_list lru)
> {
> - struct pagevec *pvec = &get_cpu_var(lru_add_pvecs)[lru];
> + struct pagevec *pvec = &get_cpu_var(lru_add_pvec);
> +
> + if (is_active_lru(lru))
> + SetPageActive(page);
> + else
> + ClearPageActive(page);
The whole use of `enum lru_list' here has always made my cry, but I'll weep
about that in [4/4].
> page_cache_get(page);
> if (!pagevec_space(pvec))
> __pagevec_lru_add(pvec, lru);
> pagevec_add(pvec, page);
> - put_cpu_var(lru_add_pvecs);
> + put_cpu_var(lru_add_pvec);
> }
>
> ...
>
--
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next prev parent reply other threads:[~2013-05-15 22:53 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-13 10:21 [PATCH 0/4] Obey mark_page_accessed hint given by filesystems v2 Mel Gorman
2013-05-13 10:21 ` [PATCH 1/4] mm: Add tracepoints for LRU activation and insertions Mel Gorman
2013-05-15 17:39 ` Rik van Riel
2013-05-13 10:21 ` [PATCH 2/4] mm: pagevec: Defer deciding what LRU to add a page to until pagevec drain time Mel Gorman
2013-05-15 22:53 ` Andrew Morton [this message]
2013-05-16 14:29 ` Mel Gorman
2013-05-13 10:21 ` [PATCH 3/4] mm: Activate !PageLRU pages on mark_page_accessed if page is on local pagevec Mel Gorman
2013-05-15 17:40 ` Rik van Riel
2013-05-15 22:55 ` Andrew Morton
2013-05-16 13:41 ` Mel Gorman
2013-05-20 22:09 ` Andrew Morton
2013-05-13 10:21 ` [PATCH 4/4] mm: Remove lru parameter from __pagevec_lru_add and remove parts of pagevec API Mel Gorman
2013-05-15 17:46 ` Rik van Riel
2013-05-15 22:56 ` Andrew Morton
2013-05-16 14:19 ` Mel Gorman
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