Commit 6eaf806a authored Oct 16, 2007 by Christoph Lameter Committed by Linus Torvalds Oct 16, 2007

Memoryless nodes: Fix interleave behavior for memoryless nodes



MPOL_INTERLEAVE currently simply loops over all nodes.  Allocations on
memoryless nodes will be redirected to nodes with memory.  This results in an
imbalance because the neighboring nodes to memoryless nodes will get
significantly more interleave hits that the rest of the nodes on the system.

We can avoid this imbalance by clearing the nodes in the interleave node set
that have no memory.  If we use the node map of the memory nodes instead of
the online nodes then we have only the nodes we want.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Tested-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Acked-by: Bob Picco <bob.picco@hp.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@skynet.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 7ea1530a

mm/mempolicy.c

+3 −1

Original line number	Original line	Diff line number	Diff line
	@@ -183,7 +183,9 @@ static struct mempolicy mpol_new(int mode, nodemask_t nodes)
	switch (mode) {		switch (mode) {
	case MPOL_INTERLEAVE:		case MPOL_INTERLEAVE:
	policy->v.nodes = *nodes;		policy->v.nodes = *nodes;
	if (nodes_weight(*nodes) == 0) {		nodes_and(policy->v.nodes, policy->v.nodes,
			node_states[N_HIGH_MEMORY]);
			if (nodes_weight(policy->v.nodes) == 0) {
	kmem_cache_free(policy_cache, policy);		kmem_cache_free(policy_cache, policy);
	return ERR_PTR(-EINVAL);		return ERR_PTR(-EINVAL);
	}		}

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