[PATCH] cpuset: mark number_of_cpusets read_mostly
Mark cpuset global 'number_of_cpusets' as __read_mostly.
This global is accessed everytime a zone is considered in the zonelist loops
beneath __alloc_pages, looking for a free memory page. If number_of_cpusets
is just one, then we can short circuit the mems_allowed check.
Since this global is read alot on a hot path, and written rarely, it is an
excellent candidate for __read_mostly.
Thanks to Christoph Lameter for the suggestion.
Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 6fe28d6..681a5d5 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -62,7 +62,7 @@
* When there is only one cpuset (the root cpuset) we can
* short circuit some hooks.
*/
-int number_of_cpusets;
+int number_of_cpusets __read_mostly;
/* See "Frequency meter" comments, below. */