[PATCH] cpuset semaphore depth check optimize

[linux-2.6] / kernel / cpuset.c

diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 407b5f0a8c8eeed2aea648b08748771dd284b3d7..79866bc6b3a154d06c4b42daa3daec60aa96ebd9 100644 (file)
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -180,6 +180,8 @@ static struct super_block *cpuset_sb = NULL;
  */
 
 static DECLARE_MUTEX(cpuset_sem);
+static struct task_struct *cpuset_sem_owner;
+static int cpuset_sem_depth;
 
 /*
  * The global cpuset semaphore cpuset_sem can be needed by the
@@ -200,16 +202,19 @@ static DECLARE_MUTEX(cpuset_sem);
 
 static inline void cpuset_down(struct semaphore *psem)
 {
-       if (current->cpuset_sem_nest_depth == 0)
+       if (cpuset_sem_owner != current) {
                down(psem);
-       current->cpuset_sem_nest_depth++;
+               cpuset_sem_owner = current;
+       }
+       cpuset_sem_depth++;
 }
 
 static inline void cpuset_up(struct semaphore *psem)
 {
-       current->cpuset_sem_nest_depth--;
-       if (current->cpuset_sem_nest_depth == 0)
+       if (--cpuset_sem_depth == 0) {
+               cpuset_sem_owner = NULL;
                up(psem);
+       }
 }
 
 /*