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authorMel Gorman <mgorman@suse.de>2014-06-05 03:10:08 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2014-06-05 03:54:08 +0400
commit664eeddeef6539247691197c1ac124d4aa872ab6 (patch)
tree568fa77ea4d8b525efeec73e398951b6089374f8 /include
parentea5e9539abf1258f23e725cb9cb25aa74efa29eb (diff)
downloadlinux-664eeddeef6539247691197c1ac124d4aa872ab6.tar.xz
mm: page_alloc: use jump labels to avoid checking number_of_cpusets
If cpusets are not in use then we still check a global variable on every page allocation. Use jump labels to avoid the overhead. Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Jan Kara <jack@suse.cz> Cc: Michal Hocko <mhocko@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/cpuset.h29
1 files changed, 26 insertions, 3 deletions
diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h
index b19d3dc2e651..ade2390ffe92 100644
--- a/include/linux/cpuset.h
+++ b/include/linux/cpuset.h
@@ -12,10 +12,31 @@
#include <linux/cpumask.h>
#include <linux/nodemask.h>
#include <linux/mm.h>
+#include <linux/jump_label.h>
#ifdef CONFIG_CPUSETS
-extern int number_of_cpusets; /* How many cpusets are defined in system? */
+extern struct static_key cpusets_enabled_key;
+static inline bool cpusets_enabled(void)
+{
+ return static_key_false(&cpusets_enabled_key);
+}
+
+static inline int nr_cpusets(void)
+{
+ /* jump label reference count + the top-level cpuset */
+ return static_key_count(&cpusets_enabled_key) + 1;
+}
+
+static inline void cpuset_inc(void)
+{
+ static_key_slow_inc(&cpusets_enabled_key);
+}
+
+static inline void cpuset_dec(void)
+{
+ static_key_slow_dec(&cpusets_enabled_key);
+}
extern int cpuset_init(void);
extern void cpuset_init_smp(void);
@@ -32,13 +53,13 @@ extern int __cpuset_node_allowed_hardwall(int node, gfp_t gfp_mask);
static inline int cpuset_node_allowed_softwall(int node, gfp_t gfp_mask)
{
- return number_of_cpusets <= 1 ||
+ return nr_cpusets() <= 1 ||
__cpuset_node_allowed_softwall(node, gfp_mask);
}
static inline int cpuset_node_allowed_hardwall(int node, gfp_t gfp_mask)
{
- return number_of_cpusets <= 1 ||
+ return nr_cpusets() <= 1 ||
__cpuset_node_allowed_hardwall(node, gfp_mask);
}
@@ -124,6 +145,8 @@ static inline void set_mems_allowed(nodemask_t nodemask)
#else /* !CONFIG_CPUSETS */
+static inline bool cpusets_enabled(void) { return false; }
+
static inline int cpuset_init(void) { return 0; }
static inline void cpuset_init_smp(void) {}