From: Andrew Morton <akpm@linux-foundation.org>
To: Shaohua Li <shli@kernel.org>
Cc: linux-mm@kvack.org, mgorman@suse.de, aarcange@redhat.com
Subject: Re: [patch 1/2 v2]compaction: abort compaction loop if lock is contended or run too long
Date: Tue, 11 Sep 2012 16:34:55 -0700 [thread overview]
Message-ID: <20120911163455.bb249a3c.akpm@linux-foundation.org> (raw)
In-Reply-To: <20120910011830.GC3715@kernel.org>
On Mon, 10 Sep 2012 09:18:30 +0800
Shaohua Li <shli@kernel.org> wrote:
> isolate_migratepages_range() might isolate none pages, for example, when
> zone->lru_lock is contended and compaction is async. In this case, we should
> abort compaction, otherwise, compact_zone will run a useless loop and make
> zone->lru_lock is even contended.
>
> ...
>
> @@ -838,12 +838,14 @@ static unsigned long compact_zone_order(
> .migratetype = allocflags_to_migratetype(gfp_mask),
> .zone = zone,
> .sync = sync,
> - .contended = contended,
> };
> INIT_LIST_HEAD(&cc.freepages);
> INIT_LIST_HEAD(&cc.migratepages);
>
> - return compact_zone(zone, &cc);
> + ret = compact_zone(zone, &cc);
> + if (contended)
> + *contended = cc.contended;
> + return ret;
> }
>
>From a quick read, `contended' is never NULL here. And defining the
interface so that `contended' must be a valid pointer is a good change,
IMO - it results in simpler and faster code.
Alas, try_to_compact_pages()'s kerneldoc altogether forgets to describe
this argument. Mel's
mm-compaction-capture-a-suitable-high-order-page-immediately-when-it-is-made-available.patch
adds a `pages' arg and forgets to document that as well.
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next prev parent reply other threads:[~2012-09-11 23:34 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-10 1:18 [patch 1/2 v2]compaction: abort compaction loop if lock is contended or run too long Shaohua Li
2012-09-10 8:11 ` Mel Gorman
2012-09-11 1:45 ` Minchan Kim
2012-09-11 8:29 ` Shaohua Li
2012-09-11 8:40 ` Minchan Kim
2012-09-11 23:34 ` Andrew Morton [this message]
2012-09-12 0:48 ` Andrea Arcangeli
2012-09-12 21:20 ` Andrew Morton
2012-09-12 23:48 ` Andrea Arcangeli
2012-09-13 0:47 ` Minchan Kim
2012-09-13 2:49 ` Shaohua Li
2012-09-13 9:38 ` Mel Gorman
2012-09-13 10:13 ` Shaohua Li
2012-09-13 16:04 ` Andrea Arcangeli
2012-09-13 16:31 ` Mel Gorman
2012-09-13 17:11 ` Andrea Arcangeli
2012-09-13 10:03 ` Mel Gorman
2012-09-12 11:08 ` Mel Gorman
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