blkio: Core implementation of throttle policy

o Actual implementation of throttling policy in block layer. Currently it
  implements READ and WRITE bytes per second throttling logic. IOPS throttling
  comes in later patches.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

1 files changed, 24 insertions, 0 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index 8d07c1b7e701..797d5095eb83 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -382,6 +382,7 @@ void blk_sync_queue(struct request_queue *q)
         del_timer_sync(&q->unplug_timer);
         del_timer_sync(&q->timeout);
         cancel_work_sync(&q->unplug_work);
+        throtl_shutdown_timer_wq(q);
 }
 EXPORT_SYMBOL(blk_sync_queue);
 
@@ -459,6 +460,8 @@ void blk_cleanup_queue(struct request_queue *q)
         if (q->elevator)
                 elevator_exit(q->elevator);
 
+        blk_throtl_exit(q);
+
         blk_put_queue(q);
 }
 EXPORT_SYMBOL(blk_cleanup_queue);
@@ -515,6 +518,11 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
                 return NULL;
         }
 
+        if (blk_throtl_init(q)) {
+                kmem_cache_free(blk_requestq_cachep, q);
+                return NULL;
+        }
+
         setup_timer(&q->backing_dev_info.laptop_mode_wb_timer,
                     laptop_mode_timer_fn, (unsigned long) q);
         init_timer(&q->unplug_timer);
@@ -1522,6 +1530,15 @@ static inline void __generic_make_request(struct bio *bio)
                         goto end_io;
                 }
 
+                blk_throtl_bio(q, &bio);
+
+                /*
+                 * If bio = NULL, bio has been throttled and will be submitted
+                 * later.
+                 */
+                if (!bio)
+                        break;
+
                 trace_block_bio_queue(q, bio);
 
                 ret = q->make_request_fn(q, bio);
@@ -2580,6 +2597,13 @@ int kblockd_schedule_work(struct request_queue *q, struct work_struct *work)
 }
 EXPORT_SYMBOL(kblockd_schedule_work);
 
+int kblockd_schedule_delayed_work(struct request_queue *q,
+                        struct delayed_work *dwork, unsigned long delay)
+{
+        return queue_delayed_work(kblockd_workqueue, dwork, delay);
+}
+EXPORT_SYMBOL(kblockd_schedule_delayed_work);
+
 int __init blk_dev_init(void)
 {
         BUILD_BUG_ON(__REQ_NR_BITS > 8 *