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path: root/drivers/block/aoe/aoecmd.c
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Diffstat (limited to 'drivers/block/aoe/aoecmd.c')
-rw-r--r--drivers/block/aoe/aoecmd.c152
1 files changed, 126 insertions, 26 deletions
diff --git a/drivers/block/aoe/aoecmd.c b/drivers/block/aoe/aoecmd.c
index b75c7db16559..19955dd72eee 100644
--- a/drivers/block/aoe/aoecmd.c
+++ b/drivers/block/aoe/aoecmd.c
@@ -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);
@@ -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;
}