oom: compare cpuset mems_allowed instead of exclusive ancestors
Instead of testing for overlap in the memory nodes of the the nearest
exclusive ancestor of both current and the candidate task, it is better to
simply test for intersection between the task's mems_allowed in their task
descriptors. This does not require taking callback_mutex since it is only
used as a hint in the badness scoring.
Tasks that do not have an intersection in their mems_allowed with the current
task are not explicitly restricted from being OOM killed because it is quite
possible that the candidate task has allocated memory there before and has
since changed its mems_allowed.
Cc: Andrea Arcangeli <andrea@suse.de>
Acked-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h
index 9e633ea..ea44d2e 100644
--- a/include/linux/cpuset.h
+++ b/include/linux/cpuset.h
@@ -45,7 +45,8 @@
__cpuset_zone_allowed_hardwall(z, gfp_mask);
}
-extern int cpuset_excl_nodes_overlap(const struct task_struct *p);
+extern int cpuset_mems_allowed_intersects(const struct task_struct *tsk1,
+ const struct task_struct *tsk2);
#define cpuset_memory_pressure_bump() \
do { \
@@ -113,7 +114,8 @@
return 1;
}
-static inline int cpuset_excl_nodes_overlap(const struct task_struct *p)
+static inline int cpuset_mems_allowed_intersects(const struct task_struct *tsk1,
+ const struct task_struct *tsk2)
{
return 1;
}