From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752957Ab2G0Xzp (ORCPT ); Fri, 27 Jul 2012 19:55:45 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:47011 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752930Ab2G0Xzn (ORCPT ); Fri, 27 Jul 2012 19:55:43 -0400 From: Tejun Heo To: linux-kernel@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, padovan@profusion.mobi, marcel@holtmann.org, peterz@infradead.org, mingo@redhat.com, davem@davemloft.net, dougthompson@xmission.com, ibm-acpi@hmh.eng.br, cbou@mail.ru, rui.zhang@intel.com, Tejun Heo Subject: [PATCH 13/15] workqueue: implement mod_delayed_work[_on]() Date: Fri, 27 Jul 2012 16:55:06 -0700 Message-Id: <1343433308-26614-14-git-send-email-tj@kernel.org> X-Mailer: git-send-email 1.7.7.3 In-Reply-To: <1343433308-26614-1-git-send-email-tj@kernel.org> References: <1343433308-26614-1-git-send-email-tj@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Workqueue was lacking a mechanism to modify the timeout of an already pending delayed_work. delayed_work users have been working around this using several methods - using an explicit timer + work item, messing directly with delayed_work->timer, and canceling before re-queueing, all of which are error-prone and/or ugly. This patch implements mod_delayed_work[_on]() which behaves similarly to mod_timer() - if the delayed_work is idle, it's queued with the given delay; otherwise, its timeout is modified to the new value. Zero @delay guarantees immediate execution. Signed-off-by: Tejun Heo Cc: Linus Torvalds Cc: Andrew Morton Cc: Ingo Molnar --- include/linux/workqueue.h | 4 +++ kernel/workqueue.c | 51 +++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 55 insertions(+), 0 deletions(-) diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h index 5f4aeaa..2000030 100644 --- a/include/linux/workqueue.h +++ b/include/linux/workqueue.h @@ -390,6 +390,10 @@ extern bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq, struct delayed_work *work, unsigned long delay); extern bool queue_delayed_work(struct workqueue_struct *wq, struct delayed_work *work, unsigned long delay); +extern bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq, + struct delayed_work *dwork, unsigned long delay); +extern bool mod_delayed_work(struct workqueue_struct *wq, + struct delayed_work *dwork, unsigned long delay); extern void flush_workqueue(struct workqueue_struct *wq); extern void drain_workqueue(struct workqueue_struct *wq); diff --git a/kernel/workqueue.c b/kernel/workqueue.c index c90f00e..3839203 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -1399,6 +1399,57 @@ bool queue_delayed_work(struct workqueue_struct *wq, EXPORT_SYMBOL_GPL(queue_delayed_work); /** + * mod_delayed_work_on - modify delay of or queue a delayed work on specific CPU + * @cpu: CPU number to execute work on + * @wq: workqueue to use + * @dwork: work to queue + * @delay: number of jiffies to wait before queueing + * + * If @dwork is idle, equivalent to queue_delayed_work_on(); otherwise, + * modify @dwork's timer so that it expires after @delay. If @delay is + * zero, @work is guaranteed to be scheduled immediately regardless of its + * current state. + * + * Returns %false if @dwork was idle and queued, %true if @dwork was + * pending and its timer was modified. + */ +bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq, + struct delayed_work *dwork, unsigned long delay) +{ + int ret; + + preempt_disable(); + + do { + ret = try_to_grab_pending(&dwork->work, &dwork->timer); + } while (unlikely(ret == -EAGAIN)); + + if (likely(ret >= 0)) + __queue_delayed_work(cpu, wq, dwork, delay); + + preempt_enable(); + + /* -ENOENT from try_to_grab_pending() becomes %true */ + return ret; +} +EXPORT_SYMBOL_GPL(mod_delayed_work_on); + +/** + * mod_delayed_work - modify delay of or queue a delayed work + * @wq: workqueue to use + * @dwork: work to queue + * @delay: number of jiffies to wait before queueing + * + * mod_delayed_work_on() on local CPU. + */ +bool mod_delayed_work(struct workqueue_struct *wq, struct delayed_work *dwork, + unsigned long delay) +{ + return mod_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay); +} +EXPORT_SYMBOL_GPL(mod_delayed_work); + +/** * worker_enter_idle - enter idle state * @worker: worker which is entering idle state * -- 1.7.7.3