From b204f13cb3738ba7417c4fed95f30aabc8f19168 Mon Sep 17 00:00:00 2001
From: Tejun Heo <tj@kernel.org>
Date: Wed, 2 Mar 2011 11:32:47 +0100
Subject: [PATCH] --- yaml --- r: 234894 b: refs/heads/master c:
 eb8c1e2c830fc25c93bc94e215ed387fe142a98d h: refs/heads/master v: v3

---
 [refs]                             |  2 +-
 trunk/arch/x86/mm/numa_64.c        | 11 ++++++++++-
 trunk/arch/x86/mm/numa_emulation.c |  6 +++++-
 3 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/[refs] b/[refs]
index 49f0c3982697..99d1f92fc9f2 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: ce0033307f1b45e23e0c149f56ea4855eb4687ce
+refs/heads/master: eb8c1e2c830fc25c93bc94e215ed387fe142a98d
diff --git a/trunk/arch/x86/mm/numa_64.c b/trunk/arch/x86/mm/numa_64.c
index 541746fdeb4b..74064e8ae79f 100644
--- a/trunk/arch/x86/mm/numa_64.c
+++ b/trunk/arch/x86/mm/numa_64.c
@@ -392,11 +392,12 @@ void __init numa_reset_distance(void)
 {
 	size_t size = numa_distance_cnt * numa_distance_cnt * sizeof(numa_distance[0]);
 
+	/* numa_distance could be 1LU marking allocation failure, test cnt */
 	if (numa_distance_cnt)
 		memblock_x86_free_range(__pa(numa_distance),
 					__pa(numa_distance) + size);
 	numa_distance_cnt = 0;
-	numa_distance = NULL;
+	numa_distance = NULL;	/* enable table creation */
 }
 
 static int __init numa_alloc_distance(void)
@@ -447,6 +448,14 @@ static int __init numa_alloc_distance(void)
  * Set the distance from node @from to @to to @distance.  If distance table
  * doesn't exist, one which is large enough to accomodate all the currently
  * known nodes will be created.
+ *
+ * If such table cannot be allocated, a warning is printed and further
+ * calls are ignored until the distance table is reset with
+ * numa_reset_distance().
+ *
+ * If @from or @to is higher than the highest known node at the time of
+ * table creation or @distance doesn't make sense, the call is ignored.
+ * This is to allow simplification of specific NUMA config implementations.
  */
 void __init numa_set_distance(int from, int to, int distance)
 {
diff --git a/trunk/arch/x86/mm/numa_emulation.c b/trunk/arch/x86/mm/numa_emulation.c
index 0afa25d967ba..aeecea93820f 100644
--- a/trunk/arch/x86/mm/numa_emulation.c
+++ b/trunk/arch/x86/mm/numa_emulation.c
@@ -379,7 +379,11 @@ void __init numa_emulation(struct numa_meminfo *numa_meminfo, int numa_dist_cnt)
 		if (emu_nid_to_phys[i] == NUMA_NO_NODE)
 			emu_nid_to_phys[i] = 0;
 
-	/* transform distance table */
+	/*
+	 * Transform distance table.  numa_set_distance() ignores all
+	 * out-of-bound distances.  Just call it for every possible node
+	 * combination.
+	 */
 	numa_reset_distance();
 	for (i = 0; i < MAX_NUMNODES; i++) {
 		for (j = 0; j < MAX_NUMNODES; j++) {