4 files changed, 140 insertions, 37 deletions

diff --git a/drivers/block/aoe/aoe.h b/drivers/block/aoe/aoe.h
index 175649468c95..025c41d3cb33 100644
--- a/drivers/block/aoe/aoe.h
+++ b/drivers/block/aoe/aoe.h
@@ -1,5 +1,5 @@
-/* Copyright (c) 2012 Coraid, Inc.  See COPYING for GPL terms. */
-#define VERSION "81"
+/* Copyright (c) 2013 Coraid, Inc.  See COPYING for GPL terms. */
+#define VERSION "83"
 #define AOE_MAJOR 152
 #define DEVICE_NAME "aoe"
 
@@ -196,9 +196,11 @@ struct ktstate {
 	struct completion rendez;
 	struct task_struct *task;
 	wait_queue_head_t *waitq;
-	int (*fn) (void);
-	char *name;
+	int (*fn) (int);
+	char name[12];
 	spinlock_t *lock;
+	int id;
+	int active;
 };
 
 int aoeblk_init(void);
@@ -222,6 +224,7 @@ int aoecmd_init(void);
 struct sk_buff *aoecmd_ata_id(struct aoedev *);
 void aoe_freetframe(struct frame *);
 void aoe_flush_iocq(void);
+void aoe_flush_iocq_by_index(int);
 void aoe_end_request(struct aoedev *, struct request *, int);
 int aoe_ktstart(struct ktstate *k);
 void aoe_ktstop(struct ktstate *k);
diff --git a/drivers/block/aoe/aoecmd.c b/drivers/block/aoe/aoecmd.c
index fc803ecbbce4..99cb944a002d 100644
--- a/drivers/block/aoe/aoecmd.c
+++ b/drivers/block/aoe/aoecmd.c
@@ -1,4 +1,4 @@
-/* Copyright (c) 2012 Coraid, Inc.  See COPYING for GPL terms. */
+/* Copyright (c) 2013 Coraid, Inc.  See COPYING for GPL terms. */
 /*
  * aoecmd.c
  * Filesystem request handling methods
@@ -35,14 +35,27 @@ module_param(aoe_maxout, int, 0644);
 MODULE_PARM_DESC(aoe_maxout,
 	"Only aoe_maxout outstanding packets for every MAC on eX.Y.");
 
-static wait_queue_head_t ktiowq;
-static struct ktstate kts;
+/* The number of online cpus during module initialization gives us a
+ * convenient heuristic cap on the parallelism used for ktio threads
+ * doing I/O completion.  It is not important that the cap equal the
+ * actual number of running CPUs at any given time, but because of CPU
+ * hotplug, we take care to use ncpus instead of using
+ * num_online_cpus() after module initialization.
+ */
+static int ncpus;
+
+/* mutex lock used for synchronization while thread spawning */
+static DEFINE_MUTEX(ktio_spawn_lock);
+
+static wait_queue_head_t *ktiowq;
+static struct ktstate *kts;
 
 /* io completion queue */
-static struct {
+struct iocq_ktio {
 	struct list_head head;
 	spinlock_t lock;
-} iocq;
+};
+static struct iocq_ktio *iocq;
 
 static struct page *empty_page;
 
@@ -1278,23 +1291,36 @@ out:
  * Returns true iff responses needing processing remain.
  */
 static int
-ktio(void)
+ktio(int id)
 {
 	struct frame *f;
 	struct list_head *pos;
 	int i;
+	int actual_id;
 
 	for (i = 0; ; ++i) {
 		if (i == MAXIOC)
 			return 1;
-		if (list_empty(&iocq.head))
+		if (list_empty(&iocq[id].head))
 			return 0;
-		pos = iocq.head.next;
+		pos = iocq[id].head.next;
 		list_del(pos);
-		spin_unlock_irq(&iocq.lock);
 		f = list_entry(pos, struct frame, head);
+		spin_unlock_irq(&iocq[id].lock);
 		ktiocomplete(f);
-		spin_lock_irq(&iocq.lock);
+
+		/* Figure out if extra threads are required. */
+		actual_id = f->t->d->aoeminor % ncpus;
+
+		if (!kts[actual_id].active) {
+			BUG_ON(id != 0);
+			mutex_lock(&ktio_spawn_lock);
+			if (!kts[actual_id].active
+				&& aoe_ktstart(&kts[actual_id]) == 0)
+				kts[actual_id].active = 1;
+			mutex_unlock(&ktio_spawn_lock);
+		}
+		spin_lock_irq(&iocq[id].lock);
 	}
 }
 
@@ -1311,7 +1337,7 @@ kthread(void *vp)
 	complete(&k->rendez);	/* tell spawner we're running */
 	do {
 		spin_lock_irq(k->lock);
-		more = k->fn();
+		more = k->fn(k->id);
 		if (!more) {
 			add_wait_queue(k->waitq, &wait);
 			__set_current_state(TASK_INTERRUPTIBLE);
@@ -1340,7 +1366,7 @@ aoe_ktstart(struct ktstate *k)
 	struct task_struct *task;
 
 	init_completion(&k->rendez);
-	task = kthread_run(kthread, k, k->name);
+	task = kthread_run(kthread, k, "%s", k->name);
 	if (task == NULL || IS_ERR(task))
 		return -ENOMEM;
 	k->task = task;
@@ -1353,13 +1379,24 @@ aoe_ktstart(struct ktstate *k)
 static void
 ktcomplete(struct frame *f, struct sk_buff *skb)
 {
+	int id;
 	ulong flags;
 
 	f->r_skb = skb;
-	spin_lock_irqsave(&iocq.lock, flags);
-	list_add_tail(&f->head, &iocq.head);
-	spin_unlock_irqrestore(&iocq.lock, flags);
-	wake_up(&ktiowq);
+	id = f->t->d->aoeminor % ncpus;
+	spin_lock_irqsave(&iocq[id].lock, flags);
+	if (!kts[id].active) {
+		spin_unlock_irqrestore(&iocq[id].lock, flags);
+		/* The thread with id has not been spawned yet,
+		 * so delegate the work to the main thread and
+		 * try spawning a new thread.
+		 */
+		id = 0;
+		spin_lock_irqsave(&iocq[id].lock, flags);
+	}
+	list_add_tail(&f->head, &iocq[id].head);
+	spin_unlock_irqrestore(&iocq[id].lock, flags);
+	wake_up(&ktiowq[id]);
 }
 
 struct sk_buff *
@@ -1706,6 +1743,17 @@ aoe_failbuf(struct aoedev *d, struct buf *buf)
 void
 aoe_flush_iocq(void)
 {
+	int i;
+
+	for (i = 0; i < ncpus; i++) {
+		if (kts[i].active)
+			aoe_flush_iocq_by_index(i);
+	}
+}
+
+void
+aoe_flush_iocq_by_index(int id)
+{
 	struct frame *f;
 	struct aoedev *d;
 	LIST_HEAD(flist);
@@ -1713,9 +1761,9 @@ aoe_flush_iocq(void)
 	struct sk_buff *skb;
 	ulong flags;
 
-	spin_lock_irqsave(&iocq.lock, flags);
-	list_splice_init(&iocq.head, &flist);
-	spin_unlock_irqrestore(&iocq.lock, flags);
+	spin_lock_irqsave(&iocq[id].lock, flags);
+	list_splice_init(&iocq[id].head, &flist);
+	spin_unlock_irqrestore(&iocq[id].lock, flags);
 	while (!list_empty(&flist)) {
 		pos = flist.next;
 		list_del(pos);
@@ -1738,6 +1786,8 @@ int __init
 aoecmd_init(void)
 {
 	void *p;
+	int i;
+	int ret;
 
 	/* get_zeroed_page returns page with ref count 1 */
 	p = (void *) get_zeroed_page(GFP_KERNEL | __GFP_REPEAT);
@@ -1745,22 +1795,72 @@ aoecmd_init(void)
 		return -ENOMEM;
 	empty_page = virt_to_page(p);
 
-	INIT_LIST_HEAD(&iocq.head);
-	spin_lock_init(&iocq.lock);
-	init_waitqueue_head(&ktiowq);
-	kts.name = "aoe_ktio";
-	kts.fn = ktio;
-	kts.waitq = &ktiowq;
-	kts.lock = &iocq.lock;
-	return aoe_ktstart(&kts);
+	ncpus = num_online_cpus();
+
+	iocq = kcalloc(ncpus, sizeof(struct iocq_ktio), GFP_KERNEL);
+	if (!iocq)
+		return -ENOMEM;
+
+	kts = kcalloc(ncpus, sizeof(struct ktstate), GFP_KERNEL);
+	if (!kts) {
+		ret = -ENOMEM;
+		goto kts_fail;
+	}
+
+	ktiowq = kcalloc(ncpus, sizeof(wait_queue_head_t), GFP_KERNEL);
+	if (!ktiowq) {
+		ret = -ENOMEM;
+		goto ktiowq_fail;
+	}
+
+	mutex_init(&ktio_spawn_lock);
+
+	for (i = 0; i < ncpus; i++) {
+		INIT_LIST_HEAD(&iocq[i].head);
+		spin_lock_init(&iocq[i].lock);
+		init_waitqueue_head(&ktiowq[i]);
+		snprintf(kts[i].name, sizeof(kts[i].name), "aoe_ktio%d", i);
+		kts[i].fn = ktio;
+		kts[i].waitq = &ktiowq[i];
+		kts[i].lock = &iocq[i].lock;
+		kts[i].id = i;
+		kts[i].active = 0;
+	}
+	kts[0].active = 1;
+	if (aoe_ktstart(&kts[0])) {
+		ret = -ENOMEM;
+		goto ktstart_fail;
+	}
+	return 0;
+
+ktstart_fail:
+	kfree(ktiowq);
+ktiowq_fail:
+	kfree(kts);
+kts_fail:
+	kfree(iocq);
+
+	return ret;
 }
 
 void
 aoecmd_exit(void)
 {
-	aoe_ktstop(&kts);
+	int i;
+
+	for (i = 0; i < ncpus; i++)
+		if (kts[i].active)
+			aoe_ktstop(&kts[i]);
+
 	aoe_flush_iocq();
 
+	/* Free up the iocq and thread speicific configuration
+	* allocated during startup.
+	*/
+	kfree(iocq);
+	kfree(kts);
+	kfree(ktiowq);
+
 	free_page((unsigned long) page_address(empty_page));
 	empty_page = NULL;
 }
diff --git a/drivers/block/aoe/aoedev.c b/drivers/block/aoe/aoedev.c
index 98f2965778b9..784c92e038d1 100644
--- a/drivers/block/aoe/aoedev.c
+++ b/drivers/block/aoe/aoedev.c
@@ -1,4 +1,4 @@
-/* Copyright (c) 2012 Coraid, Inc.  See COPYING for GPL terms. */
+/* Copyright (c) 2013 Coraid, Inc.  See COPYING for GPL terms. */
 /*
  * aoedev.c
  * AoE device utility functions; maintains device list.
@@ -518,7 +518,6 @@ void
 aoedev_exit(void)
 {
 	flush_scheduled_work();
-	aoe_flush_iocq();
 	flush(NULL, 0, EXITING);
 }
 
diff --git a/drivers/block/aoe/aoenet.c b/drivers/block/aoe/aoenet.c
index 71d3ea8d3006..63773a90581d 100644
--- a/drivers/block/aoe/aoenet.c
+++ b/drivers/block/aoe/aoenet.c
@@ -1,4 +1,4 @@
-/* Copyright (c) 2012 Coraid, Inc.  See COPYING for GPL terms. */
+/* Copyright (c) 2013 Coraid, Inc.  See COPYING for GPL terms. */
 /*
  * aoenet.c
  * Ethernet portion of AoE driver
@@ -52,7 +52,7 @@ static struct sk_buff_head skbtxq;
 
 /* enters with txlock held */
 static int
-tx(void) __must_hold(&txlock)
+tx(int id) __must_hold(&txlock)
 {
 	struct sk_buff *skb;
 	struct net_device *ifp;
@@ -205,7 +205,8 @@ aoenet_init(void)
 	kts.lock = &txlock;
 	kts.fn = tx;
 	kts.waitq = &txwq;
-	kts.name = "aoe_tx";
+	kts.id = 0;
+	snprintf(kts.name, sizeof(kts.name), "aoe_tx%d", kts.id);
 	if (aoe_ktstart(&kts))
 		return -EAGAIN;
 	dev_add_pack(&aoe_pt);