From: Mel Gorman <mgorman@suse.de>
To: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: linux-mm@kvack.org, Michal Nazarewicz <mina86@mina86.com>,
Marek Szyprowski <m.szyprowski@samsung.com>
Subject: Re: [PATCH] cma: cached pageblock type fixup
Date: Tue, 19 Jun 2012 17:26:43 +0100 [thread overview]
Message-ID: <20120619162643.GC8810@suse.de> (raw)
In-Reply-To: <201206191504.59994.b.zolnierkie@samsung.com>
On Tue, Jun 19, 2012 at 03:04:59PM +0200, Bartlomiej Zolnierkiewicz wrote:
> > If the page is on the wrong free list, just isolate it or move it to the
> > MIGRATE_ISOLATE free list at that point. If it has been allocated then
> > migrate it and move the resulting free page to the MIGRATE_ISOLATE list.
>
> Thanks, this makes sense but still leaves us with some page allocation vs
> alloc_contig_range() races (i.e. pages "in-flight" state being added/removed
> to/from pcp lists so not being on the freelists and not being allocated).
>
The races should not be forever or open-ended. Once the pageblock is
marked ISOLATE it should only take one pass to either move it from
MIGRATE_CMA to MIGRATE_ISOLATE free lists or to migrate the page and
free it to the MIGRATE_ISOLATE.
I would be very surprised if this cannot be properly handled in
alloc_contig_range() in a manner that does not wreck the page allocator
fast paths.
--
Mel Gorman
SUSE Labs
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prev parent reply other threads:[~2012-06-19 16:26 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-23 7:22 [PATCH] cma: cached pageblock type fixup Bartlomiej Zolnierkiewicz
2012-06-14 13:19 ` Marek Szyprowski
2012-06-19 9:00 ` Mel Gorman
2012-06-19 11:28 ` Bartlomiej Zolnierkiewicz
2012-06-19 12:00 ` Mel Gorman
2012-06-19 13:04 ` Bartlomiej Zolnierkiewicz
2012-06-19 16:26 ` Mel Gorman [this message]
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