From: Andrew Morton <akpm@linux-foundation.org>
To: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mgorman@suse.de>, Minchan Kim <minchan@kernel.org>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [patch] mm, numa: reclaim from all nodes within reclaim distance
Date: Wed, 19 Sep 2012 16:46:54 -0700 [thread overview]
Message-ID: <20120919164654.43204ba9.akpm@linux-foundation.org> (raw)
In-Reply-To: <alpine.DEB.2.00.1209180003340.16777@chino.kir.corp.google.com>
On Tue, 18 Sep 2012 00:03:57 -0700 (PDT)
David Rientjes <rientjes@google.com> wrote:
> RECLAIM_DISTANCE represents the distance between nodes at which it is
> deemed too costly to allocate from; it's preferred to try to reclaim from
> a local zone before falling back to allocating on a remote node with such
> a distance.
>
> To do this, zone_reclaim_mode is set if the distance between any two
> nodes on the system is greather than this distance. This, however, ends
> up causing the page allocator to reclaim from every zone regardless of
> its affinity.
>
> What we really want is to reclaim only from zones that are closer than
> RECLAIM_DISTANCE. This patch adds a nodemask to each node that
> represents the set of nodes that are within this distance. During the
> zone iteration, if the bit for a zone's node is set for the local node,
> then reclaim is attempted; otherwise, the zone is skipped.
zone_reclaim_mode isn't an lval if CONFIG_NUMA=n:
--- a/mm/page_alloc.c~mm-numa-reclaim-from-all-nodes-within-reclaim-distance-fix
+++ a/mm/page_alloc.c
@@ -4561,7 +4561,9 @@ void __paginginit free_area_init_node(in
for_each_online_node(i)
if (node_distance(nid, i) <= RECLAIM_DISTANCE) {
node_set(i, pgdat->reclaim_nodes);
+#ifdef CONFIG_NUMA
zone_reclaim_mode = 1;
+#endif
}
calculate_node_totalpages(pgdat, zones_size, zholes_size);
That may not be a very good fix though - can we get all this NUMAy code
out of a non-NUMA-specific code site?
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next prev parent reply other threads:[~2012-09-19 23:46 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-18 7:03 [patch] mm, numa: reclaim from all nodes within reclaim distance David Rientjes
2012-09-18 21:03 ` Andrew Morton
2012-09-18 21:44 ` David Rientjes
2012-09-19 23:46 ` Andrew Morton [this message]
2012-09-26 3:50 ` [patch -mm] mm, numa: reclaim from all nodes within reclaim distance fix fix David Rientjes
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