From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx3-rdu2.redhat.com ([66.187.233.73]:49636 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726741AbeH0Ah0 (ORCPT ); Sun, 26 Aug 2018 20:37:26 -0400 From: Waiman Long Subject: [PATCH v2 1/3] sched/core: Export wake_q functions to kernel modules Date: Sun, 26 Aug 2018 16:53:13 -0400 Message-Id: <1535316795-21560-2-git-send-email-longman@redhat.com> In-Reply-To: <1535316795-21560-1-git-send-email-longman@redhat.com> References: <1535316795-21560-1-git-send-email-longman@redhat.com> Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: "Darrick J. Wong" , Ingo Molnar , Peter Zijlstra Cc: linux-xfs@vger.kernel.org, linux-kernel@vger.kernel.org, Dave Chinner , Waiman Long The use of wake_q_add() and wake_up_q() functions help to do task wakeup without holding lock can help to reduce lock hold time. They should be available to kernel modules as well. A new task_in_wake_q() inline function is also added to check if the given task is in a wake_q. Signed-off-by: Waiman Long --- include/linux/sched/wake_q.h | 5 +++++ kernel/sched/core.c | 2 ++ 2 files changed, 7 insertions(+) diff --git a/include/linux/sched/wake_q.h b/include/linux/sched/wake_q.h index 10b19a192b2d..902bf1228d32 100644 --- a/include/linux/sched/wake_q.h +++ b/include/linux/sched/wake_q.h @@ -47,6 +47,11 @@ static inline void wake_q_init(struct wake_q_head *head) head->lastp = &head->first; } +static inline bool task_in_wake_q(struct task_struct *task) +{ + return READ_ONCE(task->wake_q.next) != NULL; +} + extern void wake_q_add(struct wake_q_head *head, struct task_struct *task); extern void wake_up_q(struct wake_q_head *head); diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 625bc9897f62..d90a2930b8ce 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -420,6 +420,7 @@ void wake_q_add(struct wake_q_head *head, struct task_struct *task) *head->lastp = node; head->lastp = &node->next; } +EXPORT_SYMBOL_GPL(wake_q_add); void wake_up_q(struct wake_q_head *head) { @@ -442,6 +443,7 @@ void wake_up_q(struct wake_q_head *head) put_task_struct(task); } } +EXPORT_SYMBOL_GPL(wake_up_q); /* * resched_curr - mark rq's current task 'to be rescheduled now'. -- 2.18.0