From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ig0-f200.google.com (mail-ig0-f200.google.com [209.85.213.200]) by kanga.kvack.org (Postfix) with ESMTP id 279F26B007E for ; Sat, 4 Jun 2016 03:20:14 -0400 (EDT) Received: by mail-ig0-f200.google.com with SMTP id lp2so32353008igb.3 for ; Sat, 04 Jun 2016 00:20:14 -0700 (PDT) Received: from www262.sakura.ne.jp (www262.sakura.ne.jp. [2001:e42:101:1:202:181:97:72]) by mx.google.com with ESMTPS id n206si4456591oif.136.2016.06.04.00.20.13 for (version=TLS1 cipher=AES128-SHA bits=128/128); Sat, 04 Jun 2016 00:20:13 -0700 (PDT) From: Tetsuo Handa Subject: [PATCH] oom_reaper: avoid pointless atomic_inc_not_zero usage. Date: Sat, 4 Jun 2016 16:19:19 +0900 Message-Id: <1465024759-8074-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp> Sender: owner-linux-mm@kvack.org List-ID: To: akpm@linux-foundation.org Cc: linux-mm@kvack.org, Tetsuo Handa , Michal Hocko , Arnd Bergmann Since commit 36324a990cf578b5 ("oom: clear TIF_MEMDIE after oom_reaper managed to unmap the address space") changed to use find_lock_task_mm() for finding a mm_struct to reap, it is guaranteed that mm->mm_users > 0 because find_lock_task_mm() returns a task_struct with ->mm != NULL. Therefore, we can safely use atomic_inc(). Signed-off-by: Tetsuo Handa Cc: Michal Hocko Cc: Arnd Bergmann Cc: Andrew Morton --- mm/oom_kill.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) diff --git a/mm/oom_kill.c b/mm/oom_kill.c index dfb1ab6..8050fa0 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -474,13 +474,8 @@ static bool __oom_reap_task(struct task_struct *tsk) p = find_lock_task_mm(tsk); if (!p) goto unlock_oom; - mm = p->mm; - if (!atomic_inc_not_zero(&mm->mm_users)) { - task_unlock(p); - goto unlock_oom; - } - + atomic_inc(&mm->mm_users); task_unlock(p); if (!down_read_trylock(&mm->mmap_sem)) { -- 1.8.3.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org