From: Mel Gorman <mgorman@techsingularity.net>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Rik van Riel <riel@redhat.com>,
David Rientjes <rientjes@google.com>,
Minchan Kim <minchan@kernel.org>, Michal Hocko <mhocko@suse.com>
Subject: Re: [PATCH v2 4/4] mm, compaction: direct freepage allocation for async direct compaction
Date: Mon, 4 Apr 2016 10:31:59 +0100 [thread overview]
Message-ID: <20160404093159.GB4773@techsingularity.net> (raw)
In-Reply-To: <1459414236-9219-5-git-send-email-vbabka@suse.cz>
On Thu, Mar 31, 2016 at 10:50:36AM +0200, Vlastimil Babka wrote:
> The goal of direct compaction is to quickly make a high-order page available
> for the pending allocation. The free page scanner can add significant latency
> when searching for migration targets, although to succeed the compaction, the
> only important limit on the target free pages is that they must not come from
> the same order-aligned block as the migrated pages.
>
What prevents the free pages being allocated from behind the migration
scanner? Having compaction abort when the scanners meet misses
compaction opportunities but it avoids the problem of Compactor A using
pageblock X as a migration target and Compactor B using pageblock X as a
migration source.
--
Mel Gorman
SUSE Labs
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next prev parent reply other threads:[~2016-04-04 9:32 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-31 8:50 [PATCH v2 0/4] reduce latency of direct async compaction Vlastimil Babka
2016-03-31 8:50 ` [PATCH v2 1/4] mm, compaction: wrap calculating first and last pfn of pageblock Vlastimil Babka
2016-03-31 8:50 ` [PATCH v2 2/4] mm, compaction: reduce spurious pcplist drains Vlastimil Babka
2016-03-31 8:50 ` [PATCH v2 3/4] mm, compaction: skip blocks where isolation fails in async direct compaction Vlastimil Babka
2016-03-31 8:50 ` [PATCH v2 4/4] mm, compaction: direct freepage allocation for " Vlastimil Babka
2016-04-04 9:31 ` Mel Gorman [this message]
2016-04-04 11:05 ` Vlastimil Babka
2016-04-11 7:13 ` Joonsoo Kim
2016-04-11 7:27 ` Vlastimil Babka
2016-04-11 7:05 ` [PATCH v2 0/4] reduce latency of direct async compaction Joonsoo Kim
2016-04-11 8:17 ` Vlastimil Babka
2016-04-12 4:49 ` Joonsoo Kim
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