[Sheepdog] [PATCH] sheep: use need_consistency_check consistently

[Liu Yuan]

On 05/15/2012 04:57 PM, Christoph Hellwig wrote:

> Move all remaining checks if we need a consistency check into
> need_consistency_check, which cleans up process_request_queue, and reduces
> the number of calls to object_is_cached which is more expensive than
> the other calls.  Pass the request directly to need_consistency_check and
> set_consistency_check and thus avoid having to deal with the object header
> inside process_request_queue.  Also remove the unused local copies variable
> while we're at it.
> 
> Signed-off-by: Christoph Hellwig <hch at lst.de>
> 
> ---
>  sheep/group.c |   48 +++++++++++++++++++++---------------------------
>  1 file changed, 21 insertions(+), 27 deletions(-)
> 
> Index: sheepdog/sheep/group.c
> ===================================================================
> --- sheepdog.orig/sheep/group.c	2012-05-15 10:34:54.000000000 +0200
> +++ sheepdog/sheep/group.c	2012-05-15 10:35:58.519971818 +0200
> @@ -988,35 +988,44 @@ int is_access_to_busy_objects(uint64_t o
>  	return 0;
>  }
>  
> -static int need_consistency_check(uint8_t opcode, uint16_t flags)
> +static int need_consistency_check(struct request *req)
>  {
> -	if (flags & SD_FLAG_CMD_IO_LOCAL)
> +	struct sd_obj_req *hdr = (struct sd_obj_req *)&req->rq;
> +
> +	if (hdr->flags & SD_FLAG_CMD_IO_LOCAL)
>  		/* only gateway fixes data consistency */
>  		return 0;
>  
> -	if (opcode != SD_OP_READ_OBJ)
> +	if (hdr->opcode != SD_OP_READ_OBJ)
>  		/* consistency is fixed when clients read data for the
>  		 * first time */
>  		return 0;
>  
> -	if (flags & SD_FLAG_CMD_WEAK_CONSISTENCY)
> +	if (hdr->flags & SD_FLAG_CMD_WEAK_CONSISTENCY)
> +		return 0;
> +
> +	if (is_vdi_obj(hdr->oid))
> +		/* only check consistency for data objects */
>  		return 0;
>  
> +	if (object_is_cached(hdr->oid))
> +		/* we don't check consistency for cached objects */
> +		return 0;
> +
>  	return 1;
>  }
>  
> -static inline void set_consistency_check(struct request *req, uint64_t oid)
> +static inline void set_consistency_check(struct request *req)
>  {
> -	uint32_t vdi_id = oid_to_vid(oid);
> +	struct sd_obj_req *hdr = (struct sd_obj_req *)&req->rq;
> +	uint32_t vdi_id = oid_to_vid(hdr->oid);
> +	uint32_t idx = data_oid_to_idx(hdr->oid);
>  	struct data_object_bmap *bmap;
>  
> -	if (is_vdi_obj(oid))
> -		return;
> -
>  	req->check_consistency = 1;
>  	list_for_each_entry(bmap, &sys->consistent_obj_list, list) {
>  		if (bmap->vdi_id == vdi_id) {
> -			if (test_bit(data_oid_to_idx(oid), bmap->dobjs))
> +			if (test_bit(idx, bmap->dobjs))
>  				req->check_consistency = 0;
>  			break;
>  		}
> @@ -1031,27 +1040,12 @@ static void process_request_queue(void)
>  		list_del(&req->request_list);
>  
>  		if (is_io_op(req->op)) {
> -			struct sd_obj_req *hdr = (struct sd_obj_req *)&req->rq;
> -			int copies = sys->nr_copies;
> -
> -			if (copies > req->vnodes->nr_zones)
> -				copies = req->vnodes->nr_zones;
> -
>  			list_add_tail(&req->request_list,
>  				      &sys->outstanding_req_list);
> -
> -			if (!(req->rq.flags & SD_FLAG_CMD_IO_LOCAL) &&
> -			    object_is_cached(hdr->oid)) {
> -				/* If we have cache of it we are at its service. */
> -				sys->nr_outstanding_io++;
> -				queue_work(sys->gateway_wqueue, &req->work);
> -				continue;
> -			}
> -
>  			sys->nr_outstanding_io++;
>  
> -			if (need_consistency_check(req->rq.opcode, req->rq.flags))
> -				set_consistency_check(req, hdr->oid);
> +			if (need_consistency_check(req))
> +				set_consistency_check(req);
>  
>  			if (req->rq.flags & SD_FLAG_CMD_IO_LOCAL)
>  				queue_work(sys->io_wqueue, &req->work);


Applied, thanks.

Yuan