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authorYinghai Lu <yinghai@kernel.org>2009-11-21 00:23:37 -0800
committerIngo Molnar <mingo@elte.hu>2009-11-23 10:06:24 +0100
commitd9c2d5ac6af87b4491bff107113aaf16f6c2b2d9 (patch)
tree5cb605d6396a0572dabf2b6152bb26fea425e376 /arch/x86/mm
parent021428ad1418cf3c386a1a0157140c3ea29b17ef (diff)
x86, numa: Use near(er) online node instead of roundrobin for NUMA
CPU to node mapping is set via the following sequence: 1. numa_init_array(): Set up roundrobin from cpu to online node 2. init_cpu_to_node(): Set that according to apicid_to_node[] according to srat only handle the node that is online, and leave other cpu on node without ram (aka not online) to still roundrobin. 3. later call srat_detect_node for Intel/AMD, will use first_online node or nearby node. Problem is that setup_per_cpu_areas() is not called between 2 and 3, the per_cpu for cpu on node with ram is on different node, and could put that on node with two hops away. So try to optimize this and add find_near_online_node() and call init_cpu_to_node(). Signed-off-by: Yinghai Lu <yinghai@kernel.org> Cc: Tejun Heo <tj@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: David Rientjes <rientjes@google.com> Cc: Andrew Morton <akpm@linux-foundation.org> LKML-Reference: <4B07A739.3030104@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/mm')
-rw-r--r--arch/x86/mm/numa_64.c21
1 files changed, 20 insertions, 1 deletions
diff --git a/arch/x86/mm/numa_64.c b/arch/x86/mm/numa_64.c
index 3acd870d316..83bbc70d11b 100644
--- a/arch/x86/mm/numa_64.c
+++ b/arch/x86/mm/numa_64.c
@@ -764,6 +764,25 @@ static __init int numa_setup(char *opt)
early_param("numa", numa_setup);
#ifdef CONFIG_NUMA
+
+static __init int find_near_online_node(int node)
+{
+ int n, val;
+ int min_val = INT_MAX;
+ int best_node = -1;
+
+ for_each_online_node(n) {
+ val = node_distance(node, n);
+
+ if (val < min_val) {
+ min_val = val;
+ best_node = n;
+ }
+ }
+
+ return best_node;
+}
+
/*
* Setup early cpu_to_node.
*
@@ -795,7 +814,7 @@ void __init init_cpu_to_node(void)
if (node == NUMA_NO_NODE)
continue;
if (!node_online(node))
- continue;
+ node = find_near_online_node(node);
numa_set_node(cpu, node);
}
}