mm, memcg: move all oom handling to memcontrol.c

By globally defining check_panic_on_oom(), the memcg oom handler can be
moved entirely to mm/memcontrol.c.  This removes the ugly #ifdef in the
oom killer and cleans up the code.

Signed-off-by: David Rientjes <rientjes@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 21 deletions

diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index a3a32ae02e9d..198600861638 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -556,8 +556,8 @@ void oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
 /*
  * Determines whether the kernel must panic because of the panic_on_oom sysctl.
  */
-static void check_panic_on_oom(enum oom_constraint constraint, gfp_t gfp_mask,
-                                int order, const nodemask_t *nodemask)
+void check_panic_on_oom(enum oom_constraint constraint, gfp_t gfp_mask,
+                        int order, const nodemask_t *nodemask)
 {
         if (likely(!sysctl_panic_on_oom))
                 return;
@@ -575,25 +575,6 @@ static void check_panic_on_oom(enum oom_constraint constraint, gfp_t gfp_mask,
                 sysctl_panic_on_oom == 2 ? "compulsory" : "system-wide");
 }
 
-#ifdef CONFIG_MEMCG
-void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
-                              int order)
-{
-        /*
-         * If current has a pending SIGKILL, then automatically select it.  The
-         * goal is to allow it to allocate so that it may quickly exit and free
-         * its memory.
-         */
-        if (fatal_signal_pending(current)) {
-                set_thread_flag(TIF_MEMDIE);
-                return;
-        }
-
-        check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, order, NULL);
-        __mem_cgroup_out_of_memory(memcg, gfp_mask, order);
-}
-#endif
-
 static BLOCKING_NOTIFIER_HEAD(oom_notify_list);
 
 int register_oom_notifier(struct notifier_block *nb)