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authorJack Steiner <steiner@sgi.com>2010-05-27 01:42:51 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2010-05-27 20:12:44 +0400
commit0ac0c0d0f837c499afd02a802f9cf52d3027fa3b (patch)
treec20a7306d4b727722556af1aa5565855686aee07 /include/linux/nodemask.h
parent6adef3ebe570bcde67fd6c16101451ddde5712b5 (diff)
downloadlinux-0ac0c0d0f837c499afd02a802f9cf52d3027fa3b.tar.xz
cpusets: randomize node rotor used in cpuset_mem_spread_node()
Some workloads that create a large number of small files tend to assign too many pages to node 0 (multi-node systems). Part of the reason is that the rotor (in cpuset_mem_spread_node()) used to assign nodes starts at node 0 for newly created tasks. This patch changes the rotor to be initialized to a random node number of the cpuset. [akpm@linux-foundation.org: fix layout] [Lee.Schermerhorn@hp.com: Define stub numa_random() for !NUMA configuration] Signed-off-by: Jack Steiner <steiner@sgi.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Paul Menage <menage@google.com> Cc: Jack Steiner <steiner@sgi.com> Cc: Robin Holt <holt@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/nodemask.h')
-rw-r--r--include/linux/nodemask.h8
1 files changed, 8 insertions, 0 deletions
diff --git a/include/linux/nodemask.h b/include/linux/nodemask.h
index dba35e413371..8a8f1d09c133 100644
--- a/include/linux/nodemask.h
+++ b/include/linux/nodemask.h
@@ -66,6 +66,8 @@
* int num_online_nodes() Number of online Nodes
* int num_possible_nodes() Number of all possible Nodes
*
+ * int node_random(mask) Random node with set bit in mask
+ *
* int node_online(node) Is some node online?
* int node_possible(node) Is some node possible?
*
@@ -430,6 +432,10 @@ static inline void node_set_offline(int nid)
node_clear_state(nid, N_ONLINE);
nr_online_nodes = num_node_state(N_ONLINE);
}
+
+#define node_random(mask) __node_random(&(mask))
+extern int __node_random(const nodemask_t *maskp);
+
#else
static inline int node_state(int node, enum node_states state)
@@ -460,6 +466,8 @@ static inline int num_node_state(enum node_states state)
#define node_set_online(node) node_set_state((node), N_ONLINE)
#define node_set_offline(node) node_clear_state((node), N_ONLINE)
+
+static inline int node_random(const nodemask_t mask) { return 0; }
#endif
#define node_online_map node_states[N_ONLINE]