[PATCH] cpusets: confine oom_killer to mem_exclusive cpuset

Now the real motivation for this cpuset mem_exclusive patch series seems
trivial.

This patch keeps a task in or under one mem_exclusive cpuset from provoking an
oom kill of a task under a non-overlapping mem_exclusive cpuset.  Since only
interrupt and GFP_ATOMIC allocations are allowed to escape mem_exclusive
containment, there is little to gain from oom killing a task under a
non-overlapping mem_exclusive cpuset, as almost all kernel and user memory
allocation must come from disjoint memory nodes.

This patch enables configuring a system so that a runaway job under one
mem_exclusive cpuset cannot cause the killing of a job in another such cpuset
that might be using very high compute and memory resources for a prolonged
time.

Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h
index 1fe1c3e..24062a1 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)
 {