From 61eafb00d55dfbccdfce543c6b60e369ff4f8f18 Mon Sep 17 00:00:00 2001 From: David Rientjes Date: Wed, 20 Jun 2012 12:52:58 -0700 Subject: [PATCH] mm, oom: fix and cleanup oom score calculations The divide in p->signal->oom_score_adj * totalpages / 1000 within oom_badness() was causing an overflow of the signed long data type. This adds both the root bias and p->signal->oom_score_adj before doing the normalization which fixes the issue and also cleans up the calculation. Tested-by: Dave Jones Signed-off-by: David Rientjes Cc: KOSAKI Motohiro Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/oom_kill.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 416637f0e924..77775138e930 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -184,6 +184,7 @@ unsigned long oom_badness(struct task_struct *p, struct mem_cgroup *memcg, const nodemask_t *nodemask, unsigned long totalpages) { long points; + long adj; if (oom_unkillable_task(p, memcg, nodemask)) return 0; @@ -192,7 +193,8 @@ unsigned long oom_badness(struct task_struct *p, struct mem_cgroup *memcg, if (!p) return 0; - if (p->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) { + adj = p->signal->oom_score_adj; + if (adj == OOM_SCORE_ADJ_MIN) { task_unlock(p); return 0; } @@ -210,14 +212,11 @@ unsigned long oom_badness(struct task_struct *p, struct mem_cgroup *memcg, * implementation used by LSMs. */ if (has_capability_noaudit(p, CAP_SYS_ADMIN)) - points -= 30 * totalpages / 1000; + adj -= 30; - /* - * /proc/pid/oom_score_adj ranges from -1000 to +1000 such that it may - * either completely disable oom killing or always prefer a certain - * task. - */ - points += p->signal->oom_score_adj * totalpages / 1000; + /* Normalize to oom_score_adj units */ + adj *= totalpages / 1000; + points += adj; /* * Never return 0 for an eligible task regardless of the root bonus and -- 2.30.2