linux-kernel - [RFC 1/1] workqueue: Add mod_delayed

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1308954457-21487-2-git-send-email-padovan@profusion.mobi>
Date:	Fri, 24 Jun 2011 19:27:37 -0300
From:	"Gustavo F. Padovan" <padovan@...fusion.mobi>
To:	tj@...nel.org
Cc:	linux-kernel@...r.kernel.org, padovan@...fusion.mobi,
	marcel@...tmann.org, a.p.zijlstra@...llo.nl,
	akpm@...ux-foundation.org
Subject: [RFC 1/1] workqueue: Add mod_delayed_work()

mod_delayed_work() updates a timer if the work is pending otherwise calls
queue_delayed_work_on() to queue the work with the specified delay.

Call cancel_delayed_work_sync() and then queue_delayed_work() again to
change a timer's delays is too expensive (and requires process context).
Istead we call mod_delayed_work() to only modify the timer's timeout.

LKML-Reference: <20110203161906.GG2570@....dyndns.org>
Signed-off-by: Gustavo F. Padovan <padovan@...fusion.mobi>
---
 include/linux/workqueue.h |    2 ++
 kernel/workqueue.c        |   26 ++++++++++++++++++++++++++
 2 files changed, 28 insertions(+), 0 deletions(-)

diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h
index 2be2887..44f24a4 100644
--- a/include/linux/workqueue.h
+++ b/include/linux/workqueue.h
@@ -349,6 +349,8 @@ extern void destroy_workqueue(struct workqueue_struct *wq);
 extern int queue_work(struct workqueue_struct *wq, struct work_struct *work);
 extern int queue_work_on(int cpu, struct workqueue_struct *wq,
 			struct work_struct *work);
+extern int mod_delayed_work(struct workqueue_struct *wq,
+			struct delayed_work *work, unsigned long delay);
 extern int queue_delayed_work(struct workqueue_struct *wq,
 			struct delayed_work *work, unsigned long delay);
 extern int queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 25fb1b0..f8b59ea 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1108,6 +1108,32 @@ static void delayed_work_timer_fn(unsigned long __data)
 }
 
 /**
+ * mod_delayed_work - queue work on a workqueue after delay
+ * @wq: workqueue to use
+ * @dwork: delayable work to queue
+ * @delay: number of jiffies to wait before queueing
+ *
+ * Returns 0 if @work was already on a queue, non-zero otherwise.
+ *
+ */
+int mod_delayed_work(struct workqueue_struct *wq,
+			struct delayed_work *dwork, unsigned long delay)
+{
+	struct timer_list *timer = &dwork->timer;
+	struct work_struct *work = &dwork->work;
+
+	if (!test_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work)))
+		return queue_delayed_work_on(-1, wq, dwork, delay);
+
+	BUG_ON(!timer_pending(timer));
+
+	mod_timer(timer, jiffies + delay);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(mod_delayed_work);
+
+/**
  * queue_delayed_work - queue work on a workqueue after delay
  * @wq: workqueue to use
  * @dwork: delayable work to queue
-- 
1.7.5.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/