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authorTejun Heo <tj@kernel.org>2011-03-02 11:32:47 +0100
committerTejun Heo <tj@kernel.org>2011-03-02 16:34:21 +0100
commiteb8c1e2c830fc25c93bc94e215ed387fe142a98d (patch)
tree21c87bb959e98a1639f6de575f8a630c4cb4e261 /arch/x86/mm/numa_64.c
parentce0033307f1b45e23e0c149f56ea4855eb4687ce (diff)
x86-64, NUMA: Better explain numa_distance handling
Handling of out-of-bounds distances and allocation failure can use better documentation. Add it. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Yinghai Lu <yinghai@kernel.org> Acked-by: David Rientjes <rientjes@google.com>
Diffstat (limited to 'arch/x86/mm/numa_64.c')
-rw-r--r--arch/x86/mm/numa_64.c11
1 files changed, 10 insertions, 1 deletions
diff --git a/arch/x86/mm/numa_64.c b/arch/x86/mm/numa_64.c
index 541746fdeb4b..74064e8ae79f 100644
--- a/arch/x86/mm/numa_64.c
+++ b/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)
{