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-rw-r--r--block/blk-throttle.c69
1 files changed, 44 insertions, 25 deletions
diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 8ee8e4e0a2ba..918d22240856 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -932,31 +932,26 @@ static int throtl_select_dispatch(struct throtl_service_queue *parent_sq)
return nr_disp;
}
+/**
+ * throtl_pending_timer_fn - timer function for service_queue->pending_timer
+ * @arg: the throtl_service_queue being serviced
+ *
+ * This timer is armed when a child throtl_grp with active bio's become
+ * pending and queued on the service_queue's pending_tree and expires when
+ * the first child throtl_grp should be dispatched. This function
+ * dispatches bio's from the children throtl_grps and kicks
+ * throtl_data->dispatch_work if there are bio's ready to be issued.
+ */
static void throtl_pending_timer_fn(unsigned long arg)
{
struct throtl_service_queue *sq = (void *)arg;
struct throtl_data *td = sq_to_td(sq);
-
- queue_work(kthrotld_workqueue, &td->dispatch_work);
-}
-
-/* work function to dispatch throttled bios */
-void blk_throtl_dispatch_work_fn(struct work_struct *work)
-{
- struct throtl_data *td = container_of(work, struct throtl_data,
- dispatch_work);
- struct throtl_service_queue *sq = &td->service_queue;
struct request_queue *q = td->queue;
- struct bio_list bio_list_on_stack;
- struct bio *bio;
- struct blk_plug plug;
bool dispatched = false;
- int rw, ret;
+ int ret;
spin_lock_irq(q->queue_lock);
- bio_list_init(&bio_list_on_stack);
-
while (true) {
throtl_log(sq, "dispatch nr_queued=%u read=%u write=%u",
td->nr_queued[READ] + td->nr_queued[WRITE],
@@ -964,10 +959,6 @@ void blk_throtl_dispatch_work_fn(struct work_struct *work)
ret = throtl_select_dispatch(sq);
if (ret) {
- for (rw = READ; rw <= WRITE; rw++) {
- bio_list_merge(&bio_list_on_stack, &sq->bio_lists[rw]);
- bio_list_init(&sq->bio_lists[rw]);
- }
throtl_log(sq, "bios disp=%u", ret);
dispatched = true;
}
@@ -981,13 +972,41 @@ void blk_throtl_dispatch_work_fn(struct work_struct *work)
spin_lock_irq(q->queue_lock);
}
+ if (dispatched)
+ queue_work(kthrotld_workqueue, &td->dispatch_work);
+
spin_unlock_irq(q->queue_lock);
+}
- /*
- * If we dispatched some requests, unplug the queue to make sure
- * immediate dispatch
- */
- if (dispatched) {
+/**
+ * blk_throtl_dispatch_work_fn - work function for throtl_data->dispatch_work
+ * @work: work item being executed
+ *
+ * This function is queued for execution when bio's reach the bio_lists[]
+ * of throtl_data->service_queue. Those bio's are ready and issued by this
+ * function.
+ */
+void blk_throtl_dispatch_work_fn(struct work_struct *work)
+{
+ struct throtl_data *td = container_of(work, struct throtl_data,
+ dispatch_work);
+ struct throtl_service_queue *td_sq = &td->service_queue;
+ struct request_queue *q = td->queue;
+ struct bio_list bio_list_on_stack;
+ struct bio *bio;
+ struct blk_plug plug;
+ int rw;
+
+ bio_list_init(&bio_list_on_stack);
+
+ spin_lock_irq(q->queue_lock);
+ for (rw = READ; rw <= WRITE; rw++) {
+ bio_list_merge(&bio_list_on_stack, &td_sq->bio_lists[rw]);
+ bio_list_init(&td_sq->bio_lists[rw]);
+ }
+ spin_unlock_irq(q->queue_lock);
+
+ if (!bio_list_empty(&bio_list_on_stack)) {
blk_start_plug(&plug);
while((bio = bio_list_pop(&bio_list_on_stack)))
generic_make_request(bio);