3 files changed, 44 insertions, 0 deletions

diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h
index 1fe1c3ebad30..24062a1dbf61 100644
--- a/include/linux/cpuset.h
+++ b/include/linux/cpuset.h
@@ -24,6 +24,7 @@ void cpuset_update_current_mems_allowed(void);
 void cpuset_restrict_to_mems_allowed(unsigned long *nodes);
 int cpuset_zonelist_valid_mems_allowed(struct zonelist *zl);
 extern int cpuset_zone_allowed(struct zone *z, unsigned int __nocast gfp_mask);
+extern int cpuset_excl_nodes_overlap(const struct task_struct *p);
 extern struct file_operations proc_cpuset_operations;
 extern char *cpuset_task_status_allowed(struct task_struct *task, char *buffer);
 
@@ -54,6 +55,11 @@ static inline int cpuset_zone_allowed(struct zone *z,
         return 1;
 }
 
+static inline int cpuset_excl_nodes_overlap(const struct task_struct *p)
+{
+        return 1;
+}
+
 static inline char *cpuset_task_status_allowed(struct task_struct *task,
                                                         char *buffer)
 {
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 214806deca99..40c6d801dd66 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -1688,6 +1688,39 @@ done:
         return allowed;
 }
 
+/**
+ * cpuset_excl_nodes_overlap - Do we overlap @p's mem_exclusive ancestors?
+ * @p: pointer to task_struct of some other task.
+ *
+ * Description: Return true if the nearest mem_exclusive ancestor
+ * cpusets of tasks @p and current overlap.  Used by oom killer to
+ * determine if task @p's memory usage might impact the memory
+ * available to the current task.
+ *
+ * Acquires cpuset_sem - not suitable for calling from a fast path.
+ **/
+
+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(&cpuset_sem);
+        cs1 = current->cpuset;
+        if (!cs1)
+                goto done;              /* current task exiting */
+        cs2 = p->cpuset;
+        if (!cs2)
+                goto done;              /* task p is exiting */
+        cs1 = nearest_exclusive_ancestor(cs1);
+        cs2 = nearest_exclusive_ancestor(cs2);
+        overlap = nodes_intersects(cs1->mems_allowed, cs2->mems_allowed);
+done:
+        up(&cpuset_sem);
+
+        return overlap;
+}
+
 /*
  * proc_cpuset_show()
  *  - Print tasks cpuset path into seq_file.
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 3a1d46502938..5ec8da12cfd9 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -20,6 +20,7 @@
 #include <linux/swap.h>
 #include <linux/timex.h>
 #include <linux/jiffies.h>
+#include <linux/cpuset.h>
 
 /* #define DEBUG */
 
@@ -152,6 +153,10 @@ static struct task_struct * select_bad_process(void)
                         continue;
                 if (p->oomkilladj == OOM_DISABLE)
                         continue;
+                /* If p's nodes don't overlap ours, it won't help to kill p. */
+                if (!cpuset_excl_nodes_overlap(p))
+                        continue;
+
                 /*
                  * This is in the process of releasing memory so for wait it
                  * to finish before killing some other task by mistake.