Merge branch 'origin'

[pandora-kernel.git] / kernel / cpuset.c

diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 2a75e44..ba42b0a 100644 (file)
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -641,7 +641,7 @@ static void guarantee_online_mems(const struct cpuset *cs, nodemask_t *pmask)
  * task has been modifying its cpuset.
  */
 
-void cpuset_update_task_memory_state()
+void cpuset_update_task_memory_state(void)
 {
        int my_cpusets_mem_gen;
        struct task_struct *tsk = current;
@@ -1554,7 +1554,7 @@ struct ctr_struct {
  * when reading out p->cpuset, as we don't really care if it changes
  * on the next cycle, and we are not going to try to dereference it.
  */
-static inline int pid_array_load(pid_t *pidarray, int npids, struct cpuset *cs)
+static int pid_array_load(pid_t *pidarray, int npids, struct cpuset *cs)
 {
        int n = 0;
        struct task_struct *g, *p;
@@ -2149,6 +2149,33 @@ int __cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
        return allowed;
 }
 
+/**
+ * cpuset_lock - lock out any changes to cpuset structures
+ *
+ * The out of memory (oom) code needs to lock down cpusets
+ * from being changed while it scans the tasklist looking for a
+ * task in an overlapping cpuset.  Expose callback_sem via this
+ * cpuset_lock() routine, so the oom code can lock it, before
+ * locking the task list.  The tasklist_lock is a spinlock, so
+ * must be taken inside callback_sem.
+ */
+
+void cpuset_lock(void)
+{
+       down(&callback_sem);
+}
+
+/**
+ * cpuset_unlock - release lock on cpuset changes
+ *
+ * Undo the lock taken in a previous cpuset_lock() call.
+ */
+
+void cpuset_unlock(void)
+{
+       up(&callback_sem);
+}
+
 /**
  * cpuset_excl_nodes_overlap - Do we overlap @p's mem_exclusive ancestors?
  * @p: pointer to task_struct of some other task.
@@ -2158,7 +2185,7 @@ int __cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
  * determine if task @p's memory usage might impact the memory
  * available to the current task.
  *
- * Acquires callback_sem - not suitable for calling from a fast path.
+ * Call while holding callback_sem.
  **/
 
 int cpuset_excl_nodes_overlap(const struct task_struct *p)
@@ -2166,8 +2193,6 @@ int cpuset_excl_nodes_overlap(const struct task_struct *p)
        const struct cpuset *cs1, *cs2; /* my and p's cpuset ancestors */
        int overlap = 0;                /* do cpusets overlap? */
 
-       down(&callback_sem);
-
        task_lock(current);
        if (current->flags & PF_EXITING) {
                task_unlock(current);
@@ -2186,8 +2211,6 @@ int cpuset_excl_nodes_overlap(const struct task_struct *p)
 
        overlap = nodes_intersects(cs1->mems_allowed, cs2->mems_allowed);
 done:
-       up(&callback_sem);
-
        return overlap;
 }