Messages in this thread Patch in this message | | | Date | Wed, 19 Sep 2012 16:46:54 -0700 | From | Andrew Morton <> | Subject | Re: [patch] mm, numa: reclaim from all nodes within reclaim distance |
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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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