Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932914AbcCVLBr (ORCPT ); Tue, 22 Mar 2016 07:01:47 -0400 Received: from mail-wm0-f66.google.com ([74.125.82.66]:35365 "EHLO mail-wm0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758627AbcCVLBK (ORCPT ); Tue, 22 Mar 2016 07:01:10 -0400 From: Michal Hocko To: Andrew Morton Cc: , LKML , Tetsuo Handa , David Rientjes , Vladimir Davydov Subject: [PATCH 7/9] oom: make oom_reaper_list single linked Date: Tue, 22 Mar 2016 12:00:24 +0100 Message-Id: <1458644426-22973-8-git-send-email-mhocko@kernel.org> X-Mailer: git-send-email 2.7.0 In-Reply-To: <1458644426-22973-1-git-send-email-mhocko@kernel.org> References: <1458644426-22973-1-git-send-email-mhocko@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2156 Lines: 68 From: Vladimir Davydov Entries are only added/removed from oom_reaper_list at head so we can use a single linked list and hence save a word in task_struct. Signed-off-by: Vladimir Davydov Acked-by: Michal Hocko --- include/linux/sched.h | 2 +- mm/oom_kill.c | 15 +++++++-------- 2 files changed, 8 insertions(+), 9 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index acb480b581e3..d118445a332e 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1841,7 +1841,7 @@ struct task_struct { #endif int pagefault_disabled; #ifdef CONFIG_MMU - struct list_head oom_reaper_list; + struct task_struct *oom_reaper_list; #endif /* CPU-specific state of this task */ struct thread_struct thread; diff --git a/mm/oom_kill.c b/mm/oom_kill.c index b38a648558f9..af75260f32c3 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -417,7 +417,7 @@ bool oom_killer_disabled __read_mostly; */ static struct task_struct *oom_reaper_th; static DECLARE_WAIT_QUEUE_HEAD(oom_reaper_wait); -static LIST_HEAD(oom_reaper_list); +static struct task_struct *oom_reaper_list; static DEFINE_SPINLOCK(oom_reaper_lock); @@ -527,13 +527,11 @@ static int oom_reaper(void *unused) while (true) { struct task_struct *tsk = NULL; - wait_event_freezable(oom_reaper_wait, - (!list_empty(&oom_reaper_list))); + wait_event_freezable(oom_reaper_wait, oom_reaper_list != NULL); spin_lock(&oom_reaper_lock); - if (!list_empty(&oom_reaper_list)) { - tsk = list_first_entry(&oom_reaper_list, - struct task_struct, oom_reaper_list); - list_del(&tsk->oom_reaper_list); + if (oom_reaper_list != NULL) { + tsk = oom_reaper_list; + oom_reaper_list = tsk->oom_reaper_list; } spin_unlock(&oom_reaper_lock); @@ -552,7 +550,8 @@ static void wake_oom_reaper(struct task_struct *tsk) get_task_struct(tsk); spin_lock(&oom_reaper_lock); - list_add(&tsk->oom_reaper_list, &oom_reaper_list); + tsk->oom_reaper_list = oom_reaper_list; + oom_reaper_list = tsk; spin_unlock(&oom_reaper_lock); wake_up(&oom_reaper_wait); } -- 2.7.0