Merge pull request #193 from arutk/wo_improvements

Write-only cache mode improvements

src/engine/engine_rd.c

@@ -101,7 +101,7 @@ static void _ocf_read_generic_miss_complete(struct ocf_request *req, int error)
 	}
 }
 
-static inline void _ocf_read_generic_submit_hit(struct ocf_request *req)
+void ocf_read_generic_submit_hit(struct ocf_request *req)
 {
 	env_atomic_set(&req->req_remaining, ocf_engine_io_count(req));
 
@@ -135,7 +135,7 @@ err_alloc:
 	_ocf_read_generic_miss_complete(req, -OCF_ERR_NO_MEM);
 }
 
-int ocf_read_generic_do(struct ocf_request *req)
+static int _ocf_read_generic_do(struct ocf_request *req)
 {
 	struct ocf_cache *cache = req->cache;
 
@@ -191,7 +191,7 @@ int ocf_read_generic_do(struct ocf_request *req)
 
 	/* Submit IO */
 	if (ocf_engine_is_hit(req))
-		_ocf_read_generic_submit_hit(req);
+		ocf_read_generic_submit_hit(req);
 	else
 		_ocf_read_generic_submit_miss(req);
 
@@ -206,8 +206,8 @@ int ocf_read_generic_do(struct ocf_request *req)
 }
 
 static const struct ocf_io_if _io_if_read_generic_resume = {
-	.read = ocf_read_generic_do,
-	.write = ocf_read_generic_do,
+	.read = _ocf_read_generic_do,
+	.write = _ocf_read_generic_do,
 	.resume = ocf_engine_on_resume,
 };
 
@@ -294,7 +294,7 @@ int ocf_read_generic(struct ocf_request *req)
 				OCF_DEBUG_RQ(req, "NO LOCK");
 			} else {
 				/* Lock was acquired can perform IO */
-				ocf_read_generic_do(req);
+				_ocf_read_generic_do(req);
 			}
 		} else {
 			OCF_DEBUG_RQ(req, "LOCK ERROR %d", lock);

src/engine/engine_rd.h

@@ -8,6 +8,6 @@
 
 int ocf_read_generic(struct ocf_request *req);
 
-int ocf_read_generic_do(struct ocf_request *req);
+void ocf_read_generic_submit_hit(struct ocf_request *req);
 
 #endif /* ENGINE_RD_H_ */

src/engine/engine_wo.c

@@ -167,38 +167,30 @@ static void _ocf_read_wo_core_complete(struct ocf_request *req, int error)
 
 int ocf_read_wo_do(struct ocf_request *req)
 {
-	ocf_cache_t cache = req->cache;
-
-	if (ocf_engine_is_hit(req)) {
-		/* read hit - just fetch the data from cache using standard read path
-		 */
-		ocf_read_generic_do(req);
-		return 0;
-	}
-
 	ocf_req_get(req);
 
-	if (req->info.re_part) {
-		OCF_DEBUG_RQ(req, "Re-Part");
+	/* Lack of cacheline repartitioning here is deliberate. WO cache mode
+	 * reads should not affect cacheline status as reading data from the
+	 * cache is just an internal optimization. Also WO cache mode is
+	 * designed to be used with partitioning based on write life-time hints
+	 * and read requests do not carry write lifetime hint by definition.
+	 */
 
-		OCF_METADATA_LOCK_WR();
+	if (ocf_engine_is_hit(req)) {
+		/* read hit - just fetch the data from cache */
+		OCF_DEBUG_RQ(req, "Submit cache hit");
+		ocf_read_generic_submit_hit(req);
+	} else {
 
-		/* Probably some cache lines are assigned into wrong
-		 * partition. Need to move it to new one
-		 */
-		ocf_part_move(req);
-
-		OCF_METADATA_UNLOCK_WR();
+		OCF_DEBUG_RQ(req, "Submit core");
+		ocf_submit_volume_req(&req->core->volume, req,
+				_ocf_read_wo_core_complete);
 	}
 
-	OCF_DEBUG_RQ(req, "Submit core");
-	ocf_submit_volume_req(&req->core->volume, req, _ocf_read_wo_core_complete);
-
 	ocf_engine_update_request_stats(req);
 	ocf_engine_update_block_stats(req);
 
 	ocf_req_put(req);
-
 	return 0;
 }
 

src/utils/utils_io.c

@@ -236,12 +236,11 @@ void ocf_submit_cache_reqs(struct ocf_cache *cache,
 	struct ocf_io *io;
 	int err;
 	uint32_t i;
-	uint32_t entry = ocf_bytes_2_lines(cache, req->byte_position + offset) -
-			ocf_bytes_2_lines(cache, req->byte_position);
-	struct ocf_map_info *map_info = &req->map[entry];
+	uint32_t first_cl = ocf_bytes_2_lines(cache, req->byte_position +
+			offset) - ocf_bytes_2_lines(cache, req->byte_position);
 
 	ENV_BUG_ON(req->byte_length < offset + size);
-	ENV_BUG_ON(entry + reqs > req->core_line_count);
+	ENV_BUG_ON(first_cl + reqs > req->core_line_count);
 
 	cache_stats = &req->core->counters->cache_blocks;
 
@@ -253,7 +252,7 @@ void ocf_submit_cache_reqs(struct ocf_cache *cache,
 		}
 
 		addr = ocf_metadata_map_lg2phy(cache,
-					map_info[0].coll_idx);
+					req->map[first_cl].coll_idx);
 		addr *= ocf_line_size(cache);
 		addr += cache->device->metadata_offset;
 		addr += ((req->byte_position + offset) % ocf_line_size(cache));
@@ -288,7 +287,7 @@ void ocf_submit_cache_reqs(struct ocf_cache *cache,
 		}
 
 		addr  = ocf_metadata_map_lg2phy(cache,
-				map_info[i].coll_idx);
+				req->map[first_cl + i].coll_idx);
 		addr *= ocf_line_size(cache);
 		addr += cache->device->metadata_offset;
 		bytes = ocf_line_size(cache);