From: Wu Fengguang <fengguang.wu@intel.com>
To: Iram Shahzad <iram.shahzad@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>,
linux-mm@kvack.org,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Subject: Re: compaction: trying to understand the code
Date: Wed, 18 Aug 2010 23:41:30 +0800 [thread overview]
Message-ID: <20100818154130.GC9431@localhost> (raw)
In-Reply-To: <4385155269B445AEAF27DC8639A953D7@rainbow>
On Wed, Aug 18, 2010 at 05:19:21PM +0900, Iram Shahzad wrote:
> >>In other words, what is it that is supposed to increase the "inactive"
> >>or decrease the "isolated" so that isolated > inactive becomes false?
> >>
> >
> >See places that update the NR_ISOLATED_ANON and NR_ISOLATED_FILE
> >counters.
>
> Many thanks for the advice.
> So far as I understand, to come out of the loop, somehow NR_ISOLATED_*
> has to be decremented. And the code that decrements it is called here:
> mm/migrate.c migrate_pages() -> unmap_and_move()
>
> In compaction.c, migrate_pages() is called only after returning from
> isolate_migratepages().
> So if it is looping inside isolate_migratepages() function, migrate_pages()
> will not be called and hence there is no chance for NR_ISOLATED_*
> to be decremented. Am I wrong?
The loop should be waiting for the _other_ processes (doing direct
reclaims) to proceed. When there are _lots of_ ongoing page
allocations/reclaims, it makes sense to wait for them to calm down a bit?
Thanks,
Fengguang
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next prev parent reply other threads:[~2010-08-18 15:41 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-17 11:08 compaction: trying to understand the code Iram Shahzad
2010-08-17 11:10 ` Mel Gorman
2010-08-18 8:19 ` Iram Shahzad
2010-08-18 15:41 ` Wu Fengguang [this message]
2010-08-19 7:09 ` Iram Shahzad
2010-08-19 7:45 ` Wu Fengguang
2010-08-19 7:46 ` Mel Gorman
2010-08-19 8:08 ` Wu Fengguang
2010-08-19 8:15 ` Mel Gorman
2010-08-19 8:29 ` Wu Fengguang
2010-08-20 5:45 ` Iram Shahzad
2010-08-20 5:50 ` Wu Fengguang
2010-08-20 6:13 ` Iram Shahzad
2010-08-19 16:00 ` Minchan Kim
2010-08-20 5:31 ` Iram Shahzad
2010-08-20 5:34 ` Wu Fengguang
2010-08-20 9:35 ` Mel Gorman
2010-08-20 10:22 ` Minchan Kim
2010-08-22 15:31 ` Minchan Kim
2010-08-22 23:23 ` Wu Fengguang
2010-08-23 1:58 ` Minchan Kim
2010-08-23 3:03 ` Iram Shahzad
2010-08-23 9:10 ` Minchan Kim
2010-08-26 8:51 ` Mel Gorman
2010-08-23 7:18 ` Mel Gorman
2010-08-23 17:14 ` Minchan Kim
2010-08-24 0:27 ` Wu Fengguang
2010-08-24 5:07 ` Iram Shahzad
2010-08-24 6:52 ` Minchan Kim
2010-08-26 8:05 ` Iram Shahzad
2010-08-23 7:16 ` Mel Gorman
2010-08-23 9:07 ` Minchan Kim
2010-08-20 10:23 ` Wu Fengguang
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