[patch 3/5] oom: less memdie

[Nick Piggin <npiggin@suse.de>]

Don't cause all threads in all other thread groups to gain TIF_MEMDIE
otherwise we'll get a thundering herd eating out memory reserve. This
may not be the optimal scheme, but it fits our policy of allowing just
one TIF_MEMDIE in the system at once.

Signed-off-by: Nick Piggin <npiggin@suse.de>

Index: linux-2.6/mm/oom_kill.c
===================================================================
--- linux-2.6.orig/mm/oom_kill.c
+++ linux-2.6/mm/oom_kill.c
@@ -322,11 +322,12 @@ static int oom_kill_task(struct task_str
 
 	/*
 	 * kill all processes that share the ->mm (i.e. all threads),
-	 * but are in a different thread group.
+	 * but are in a different thread group. Don't let them have access
+	 * to memory reserves though, otherwise we might deplete all memory.
 	 */
 	do_each_thread(g, q) {
 		if (q->mm == mm && q->tgid != p->tgid)
-			__oom_kill_task(q, 1);
+			force_sig(SIGKILL, p);
 	} while_each_thread(g, q);
 
 	return 0;