[14/15] rbd: embed image request as blk_mq request payload

Commit Message

Hannes Reinecke Jan. 31, 2020, 10:37 a.m. UTC

Instead of allocating an image request for every block request
we can as well embed it as the payload and save the allocation.

Signed-off-by: Hannes Reinecke <[e-mail]>
---
 drivers/block/rbd.c | 56 +++++++++++++++++++++++++++++++++++------------------
 1 file changed, 37 insertions(+), 19 deletions(-)

Patch

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 9829f225c57d..cc3e5116fe58 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -324,6 +324,7 @@  typedef void (*rbd_img_request_cb_t)(struct rbd_img_request *img_request,
 enum img_req_flags {
 	IMG_REQ_CHILD,		/* initiator: block = 0, child image = 1 */
 	IMG_REQ_LAYERED,	/* ENOENT handling: normal = 0, layered = 1 */
+	IMG_REQ_EMBEDDED,	/* free handling: normal = 0, embedded = 1 */
 };
 
 enum rbd_img_state {
@@ -1640,17 +1641,10 @@  static bool rbd_dev_parent_get(struct rbd_device *rbd_dev)
  * that comprises the image request, and the Linux request pointer
  * (if there is one).
  */
-static struct rbd_img_request *rbd_img_request_create(
-					struct rbd_device *rbd_dev,
-					enum obj_operation_type op_type,
-					struct ceph_snap_context *snapc)
+static void rbd_img_request_setup(struct rbd_img_request *img_request,
+		struct rbd_device *rbd_dev, enum obj_operation_type op_type,
+		struct ceph_snap_context *snapc)
 {
-	struct rbd_img_request *img_request;
-
-	img_request = kmem_cache_zalloc(rbd_img_request_cache, GFP_NOIO);
-	if (!img_request)
-		return NULL;
-
 	img_request->rbd_dev = rbd_dev;
 	img_request->op_type = op_type;
 	if (!rbd_img_is_write(img_request))
@@ -1661,9 +1655,25 @@  static struct rbd_img_request *rbd_img_request_create(
 	if (rbd_dev_parent_get(rbd_dev))
 		img_request_layered_set(img_request);
 
+	img_request->pending_result = 0;
+	img_request->state = RBD_IMG_DONE;
 	INIT_LIST_HEAD(&img_request->lock_item);
 	INIT_LIST_HEAD(&img_request->object_extents);
 	mutex_init(&img_request->object_mutex);
+}
+
+struct rbd_img_request *rbd_img_request_create(
+					struct rbd_device *rbd_dev,
+					enum obj_operation_type op_type,
+					struct ceph_snap_context *snapc)
+{
+	struct rbd_img_request *img_request;
+
+	img_request = kmem_cache_zalloc(rbd_img_request_cache, GFP_NOIO);
+	if (!img_request)
+		return NULL;
+
+	rbd_img_request_setup(img_request, rbd_dev, op_type, snapc);
 
 	return img_request;
 }
@@ -1690,7 +1700,8 @@  static void rbd_img_request_destroy(struct rbd_img_request *img_request)
 	if (rbd_img_is_write(img_request))
 		ceph_put_snap_context(img_request->snapc);
 
-	kmem_cache_free(rbd_img_request_cache, img_request);
+	if (!test_bit(IMG_REQ_EMBEDDED, &img_request->flags))
+		kmem_cache_free(rbd_img_request_cache, img_request);
 }
 
 #define BITS_PER_OBJ	2
@@ -4780,7 +4791,7 @@  static blk_status_t rbd_queue_rq(struct blk_mq_hw_ctx *hctx,
 {
 	struct request *rq = bd->rq;
 	struct rbd_device *rbd_dev = rq->q->queuedata;
-	struct rbd_img_request *img_request;
+	struct rbd_img_request *img_request = blk_mq_rq_to_pdu(rq);
 	struct ceph_snap_context *snapc = NULL;
 	u64 offset = (u64)blk_rq_pos(rq) << SECTOR_SHIFT;
 	u64 length = blk_rq_bytes(rq);
@@ -4845,11 +4856,7 @@  static blk_status_t rbd_queue_rq(struct blk_mq_hw_ctx *hctx,
 		goto err_rq;
 	}
 
-	img_request = rbd_img_request_create(rbd_dev, op_type, snapc);
-	if (!img_request) {
-		result = -ENOMEM;
-		goto err_rq;
-	}
+	rbd_img_request_setup(img_request, rbd_dev, op_type, snapc);
 	img_request->callback = rbd_img_end_request;
 	img_request->callback_data = rq;
 	snapc = NULL; /* img_request consumes a ref */
@@ -4865,7 +4872,7 @@  static blk_status_t rbd_queue_rq(struct blk_mq_hw_ctx *hctx,
 	if (result)
 		goto err_img_request;
 
-	rbd_img_schedule(img_request, 0);
+	queue_work(rbd_wq, &img_request->work);
 	return BLK_STS_OK;
 
 err_img_request:
@@ -5043,8 +5050,19 @@  static int rbd_dev_refresh(struct rbd_device *rbd_dev)
 	return ret;
 }
 
+static int rbd_init_request(struct blk_mq_tag_set *set, struct request *rq,
+		unsigned int hctx_idx, unsigned int numa_node)
+{
+	struct rbd_img_request *img_req = blk_mq_rq_to_pdu(rq);
+
+	INIT_WORK(&img_req->work, rbd_img_handle_request_work);
+	set_bit(IMG_REQ_EMBEDDED, &img_req->flags);
+	return 0;
+}
+
 static const struct blk_mq_ops rbd_mq_ops = {
 	.queue_rq	= rbd_queue_rq,
+	.init_request	= rbd_init_request,
 };
 
 static int rbd_init_disk(struct rbd_device *rbd_dev)
@@ -5077,7 +5095,7 @@  static int rbd_init_disk(struct rbd_device *rbd_dev)
 	rbd_dev->tag_set.numa_node = NUMA_NO_NODE;
 	rbd_dev->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
 	rbd_dev->tag_set.nr_hw_queues = 1;
-	rbd_dev->tag_set.cmd_size = sizeof(struct work_struct);
+	rbd_dev->tag_set.cmd_size = sizeof(struct rbd_img_request);
 
 	err = blk_mq_alloc_tag_set(&rbd_dev->tag_set);
 	if (err)