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-rw-r--r--kernel/cpuset.c33
1 files changed, 33 insertions, 0 deletions
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 214806deca9..40c6d801dd6 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.