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: <4B8A1805.9090503@kernel.org>
Date:	Sun, 28 Feb 2010 16:15:17 +0900
From:	Tejun Heo <tj@...nel.org>
To:	Tejun Heo <tj@...nel.org>
CC:	torvalds@...ux-foundation.org, mingo@...e.hu, peterz@...radead.org,
	awalls@...ix.net, linux-kernel@...r.kernel.org, jeff@...zik.org,
	akpm@...ux-foundation.org, jens.axboe@...cle.com,
	rusty@...tcorp.com.au, cl@...ux-foundation.org,
	dhowells@...hat.com, arjan@...ux.intel.com, avi@...hat.com,
	johannes@...solutions.net, andi@...stfloor.org,
	Oleg Nesterov <oleg@...hat.com>,
	Anton Blanchard <anton@...ba.org>
Subject: [PATCH UPDATED 35/43] workqueue: implement several utility APIs

Implement the following utility APIs.

 workqueue_set_max_active()	: adjust max_active of a wq
 workqueue_congested()		: test whether a wq is contested
 work_cpu()			: determine the last / current cpu of a work
 work_busy()			: query whether a work is busy

* Anton Blanchard fixed missing ret initialization in work_busy().

Signed-off-by: Tejun Heo <tj@...nel.org>
Cc: Anton Blanchard <anton@...ba.org>
---
Missing initialization of @ret in work_busy() fixed.  The git tree and
patchset tarball are updated accordingly.  The new commit is
ad66f6442f165fccf3b17f0fb0434272a6286f31.

 git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq.git review-cmwq
 http://master.kernel.org/~tj/patches/review-cmwq.tar.gz

Thanks.

 include/linux/workqueue.h |   11 ++++-
 kernel/workqueue.c        |  108 ++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 117 insertions(+), 2 deletions(-)

diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h
index 850942a..5d1d9be 100644
--- a/include/linux/workqueue.h
+++ b/include/linux/workqueue.h
@@ -65,6 +65,10 @@ enum {
 	WORK_STRUCT_FLAG_MASK	= (1UL << WORK_STRUCT_FLAG_BITS) - 1,
 	WORK_STRUCT_WQ_DATA_MASK = ~WORK_STRUCT_FLAG_MASK,
 	WORK_STRUCT_NO_CPU	= NR_CPUS << WORK_STRUCT_FLAG_BITS,
+
+	/* bit mask for work_busy() return values */
+	WORK_BUSY_PENDING	= 1 << 0,
+	WORK_BUSY_RUNNING	= 1 << 1,
 };
 
 struct work_struct {
@@ -320,9 +324,14 @@ extern void init_workqueues(void);
 int execute_in_process_context(work_func_t fn, struct execute_work *);
 
 extern int flush_work(struct work_struct *work);
-
 extern int cancel_work_sync(struct work_struct *work);
 
+extern void workqueue_set_max_active(struct workqueue_struct *wq,
+				     int max_active);
+extern bool workqueue_congested(unsigned int cpu, struct workqueue_struct *wq);
+extern unsigned int work_cpu(struct work_struct *work);
+extern unsigned int work_busy(struct work_struct *work);
+
 /*
  * Kill off a pending schedule_delayed_work().  Note that the work callback
  * function may still be running on return from cancel_delayed_work(), unless
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index c4cb082..4c48bb6 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -205,7 +205,7 @@ struct workqueue_struct {
 	cpumask_var_t		mayday_mask;	/* cpus requesting rescue */
 	struct worker		*rescuer;	/* I: rescue worker */
 
-	int			saved_max_active; /* I: saved cwq max_active */
+	int			saved_max_active; /* W: saved cwq max_active */
 	const char		*name;		/* I: workqueue name */
 #ifdef CONFIG_LOCKDEP
 	struct lockdep_map	lockdep_map;
@@ -2594,6 +2594,112 @@ void destroy_workqueue(struct workqueue_struct *wq)
 }
 EXPORT_SYMBOL_GPL(destroy_workqueue);
 
+/**
+ * workqueue_set_max_active - adjust max_active of a workqueue
+ * @wq: target workqueue
+ * @max_active: new max_active value.
+ *
+ * Set max_active of @wq to @max_active.
+ *
+ * CONTEXT:
+ * Don't call from IRQ context.
+ */
+void workqueue_set_max_active(struct workqueue_struct *wq, int max_active)
+{
+	unsigned int cpu;
+
+	max_active = wq_clamp_max_active(max_active, wq->name);
+
+	spin_lock(&workqueue_lock);
+
+	wq->saved_max_active = max_active;
+
+	for_each_possible_cpu(cpu) {
+		struct global_cwq *gcwq = get_gcwq(cpu);
+
+		spin_lock_irq(&gcwq->lock);
+
+		if (!(wq->flags & WQ_FREEZEABLE) ||
+		    !(gcwq->flags & GCWQ_FREEZING))
+			get_cwq(gcwq->cpu, wq)->max_active = max_active;
+
+		spin_unlock_irq(&gcwq->lock);
+	}
+
+	spin_unlock(&workqueue_lock);
+}
+EXPORT_SYMBOL_GPL(workqueue_set_max_active);
+
+/**
+ * workqueue_congested - test whether a workqueue is congested
+ * @cpu: CPU in question
+ * @wq: target workqueue
+ *
+ * Test whether @wq's cpu workqueue for @cpu is congested.  There is
+ * no synchronization around this function and the test result is
+ * unreliable and only useful as advisory hints or for debugging.
+ *
+ * RETURNS:
+ * %true if congested, %false otherwise.
+ */
+bool workqueue_congested(unsigned int cpu, struct workqueue_struct *wq)
+{
+	struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
+
+	return !list_empty(&cwq->delayed_works);
+}
+EXPORT_SYMBOL_GPL(workqueue_congested);
+
+/**
+ * work_cpu - return the last known associated cpu for @work
+ * @work: the work of interest
+ *
+ * RETURNS:
+ * CPU number if @work was ever queued.  NR_CPUS otherwise.
+ */
+unsigned int work_cpu(struct work_struct *work)
+{
+	struct global_cwq *gcwq = get_work_gcwq(work);
+
+	return gcwq ? gcwq->cpu : NR_CPUS;
+}
+EXPORT_SYMBOL_GPL(work_cpu);
+
+/**
+ * work_busy - test whether a work is currently pending or running
+ * @work: the work to be tested
+ *
+ * Test whether @work is currently pending or running.  There is no
+ * synchronization around this function and the test result is
+ * unreliable and only useful as advisory hints or for debugging.
+ * Especially for reentrant wqs, the pending state might hide the
+ * running state.
+ *
+ * RETURNS:
+ * OR'd bitmask of WORK_BUSY_* bits.
+ */
+unsigned int work_busy(struct work_struct *work)
+{
+	struct global_cwq *gcwq = get_work_gcwq(work);
+	unsigned long flags;
+	unsigned int ret = 0;
+
+	if (!gcwq)
+		return false;
+
+	spin_lock_irqsave(&gcwq->lock, flags);
+
+	if (work_pending(work))
+		ret |= WORK_BUSY_PENDING;
+	if (find_worker_executing_work(gcwq, work))
+		ret |= WORK_BUSY_RUNNING;
+
+	spin_unlock_irqrestore(&gcwq->lock, flags);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(work_busy);
+
 /*
  * CPU hotplug.
  *
-- 
1.6.4.2

--
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/

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ