[PATCH] mm: oom-killer tunable

With <garloff@suse.de>

This is protect-pids, a patch to allow the admin to tune the oom killer.
The tweak is inherited between parent and child so it's easy to write a
wrapper for complex apps.

I made used_math a char at the light of later patches. Current patch
breaks alpha, but future patches will fix it.

Signed-off-by: Andrea Arcangeli <andrea@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 13 insertions, 1 deletions

diff --git a/include/linux/sched.h b/include/linux/sched.h
index b15db5dc354c..1fa591147d9f 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -614,7 +614,19 @@ struct task_struct {
 	struct key *process_keyring;	/* keyring private to this process (CLONE_THREAD) */
 	struct key *thread_keyring;	/* keyring private to this thread */
 #endif
-	unsigned short used_math;
+/*
+ * Must be changed atomically so it shouldn't be
+ * be a shareable bitflag.
+ */
+	unsigned char used_math;
+/*
+ * OOM kill score adjustment (bit shift).
+ * Cannot live together with used_math since
+ * used_math and oomkilladj can be changed at the
+ * same time, so they would race if they're in the
+ * same atomic block.
+ */
+	short oomkilladj;
 	char comm[TASK_COMM_LEN];
 /* file system info */
 	int link_count, total_link_count;