[PATCH] x86_64: Make the cpu_*_maps in kernel/sched.c read mostly

They are referred to often so avoid potential false sharing for them.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/kernel/sched.c b/kernel/sched.c
index d129e56..c0c60c9 100644 (file)
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -3980,12 +3980,12 @@ asmlinkage long sys_sched_setaffinity(pid_t pid, unsigned int len,
  * method, such as ACPI for e.g.
  */
 
-cpumask_t cpu_present_map;
+cpumask_t cpu_present_map __read_mostly;
 EXPORT_SYMBOL(cpu_present_map);
 
 #ifndef CONFIG_SMP
-cpumask_t cpu_online_map = CPU_MASK_ALL;
-cpumask_t cpu_possible_map = CPU_MASK_ALL;
+cpumask_t cpu_online_map __read_mostly = CPU_MASK_ALL;
+cpumask_t cpu_possible_map __read_mostly = CPU_MASK_ALL;
 #endif
 
 long sched_getaffinity(pid_t pid, cpumask_t *mask)