Added tracing functionality

Signed-off-by: Tomasz Rybicki <tomasz.rybicki@intel.com>

inc/ocf.h

@@ -33,5 +33,6 @@
 #include "ocf_mngt.h"
 #include "ocf_ctx.h"
 #include "ocf_err.h"
+#include "ocf_trace.h"
 
 #endif /* __OCF_H__ */

inc/ocf_io.h

@@ -76,7 +76,7 @@ struct ocf_io {
 	/**
 	 * @brief OCF IO destination class
 	 */
-	uint32_t class;
+	uint32_t io_class;
 
 	/**
 	 * @brief OCF IO direction
@@ -157,15 +157,15 @@ void *ocf_io_get_priv(struct ocf_io *io);
  * @param[in] addr OCF IO destination address
  * @param[in] bytes OCF IO size in bytes
  * @param[in] dir OCF IO direction
- * @param[in] class OCF IO destination class
+ * @param[in] io_class OCF IO destination class
  * @param[in] flags OCF IO flags
  */
 static inline void ocf_io_configure(struct ocf_io *io, uint64_t addr,
-		uint32_t bytes, uint32_t dir, uint32_t class, uint64_t flags)
+		uint32_t bytes, uint32_t dir, uint32_t io_class, uint64_t flags)
 {
 	io->addr = addr;
 	io->bytes = bytes;
-	io->class = class;
+	io->io_class = io_class;
 	io->flags = flags;
 	io->dir = dir;
 }

inc/ocf_trace.h

@@ -0,0 +1,188 @@
+/*
+ * Copyright(c) 2012-2018 Intel Corporation
+ * SPDX-License-Identifier: BSD-3-Clause-Clear
+ */
+
+#ifndef __OCF_TRACE_H__
+#define __OCF_TRACE_H__
+
+#include "ocf_def.h"
+#include "ocf_types.h"
+
+typedef uint64_t log_sid_t;
+
+#define OCF_EVENT_VERSION	1
+#define OCF_TRACING_STOP	1
+
+/**
+ * @brief OCF trace (event) type
+ */
+typedef enum {
+	/** IO trace description, this event is pushed first to indicate version
+	 * of traces, number of cores and provides details about cache */
+	ocf_event_type_cache_desc,
+
+	/** Event describing ocf core */
+	ocf_event_type_core_desc,
+
+	/** IO */
+	ocf_event_type_io,
+
+	/** IO completion */
+	ocf_event_type_io_cmpl,
+
+	/** IO in file domain */
+	ocf_event_type_io_file,
+} ocf_event_type;
+
+/**
+ * @brief Generic OCF trace event
+ */
+struct ocf_event_hdr {
+	/** Event sequence ID */
+	log_sid_t sid;
+
+	/** Time stamp */
+	uint64_t timestamp;
+
+	/** Trace event type */
+	ocf_event_type type;
+
+	/** Size of this event */
+	uint32_t size;
+};
+
+/**
+ *  @brief Cache trace description
+*/
+struct ocf_event_cache_desc {
+	/** Event header */
+	struct ocf_event_hdr hdr;
+
+	/** Cache Id */
+	ocf_cache_id_t id;
+
+	/** Cache line size */
+	ocf_cache_line_size_t cache_line_size;
+
+	/** Cache mode */
+	ocf_cache_mode_t cache_mode;
+
+	/** Cache size in bytes*/
+	uint64_t cache_size;
+
+	/** Number of cores */
+	uint32_t cores_no;
+
+	/** Number of IO queues */
+	uint32_t io_queues_no;
+
+	/** Trace version */
+	uint32_t version;
+};
+
+/**
+ *  @brief Core trace description
+*/
+struct ocf_event_core_desc {
+	/** Event header */
+	struct ocf_event_hdr hdr;
+
+	/** Core Id */
+	ocf_core_id_t id;
+
+	/** Core size in bytes */
+	uint64_t core_size;
+};
+
+/** @brief IO operation */
+typedef enum {
+	/** Read */
+	ocf_event_operation_rd = 'R',
+
+	/** Write */
+	ocf_event_operation_wr = 'W',
+
+	/** Flush */
+	ocf_event_operation_flush = 'F',
+
+	/** Discard */
+	ocf_event_operation_discard = 'D',
+} ocf_event_operation_t;
+
+/**
+ * @brief IO trace event
+ */
+struct ocf_event_io {
+	/** Trace event header */
+	struct ocf_event_hdr hdr;
+
+	/** Address of IO in bytes */
+	uint64_t addr;
+
+	/** Size of IO in bytes */
+	uint32_t len;
+
+	/** IO class of IO */
+	uint32_t io_class;
+
+	/** Core ID */
+	ocf_core_id_t core_id;
+
+	/** Operation type: read, write, trim or flush **/
+	ocf_event_operation_t operation;
+};
+
+/**
+ * @brief IO completion event
+ */
+struct ocf_event_io_cmpl {
+	/** Trace event header */
+	struct ocf_event_hdr hdr;
+
+	/** Reference event sequence ID */
+	log_sid_t rsid;
+
+	/** Was IO a cache hit or miss */
+	bool is_hit;
+};
+
+
+/** @brief Push log callback.
+ *
+ * @param[in] cache OCF cache
+ * @param[in] trace_ctx Tracing context
+ * @param[in] qid Queue Id
+ * @param[out] trace Event log
+ * @param[out] size Size of event log
+ *
+ * @return 0 If pushing trace succeeded
+ * @return Non-zero error
+ */
+typedef void (*ocf_trace_callback_t)(ocf_cache_t cache, void *trace_ctx,
+		uint32_t qid, const void* trace, const uint32_t size);
+
+/**
+ * @brief Start tracing
+ *
+ * @param[in] cache OCF cache
+ * @param[in] trace_ctx Tracing context
+ * @param[in] trace_callback Callback used for pushing logs
+ *
+ * @retval 0 Tracing started successfully
+ * @retval Non-zero Error
+ */
+int ocf_mgnt_start_trace(ocf_cache_t cache, void *trace_ctx,
+		ocf_trace_callback_t trace_callback);
+
+/**
+ * @brief Stop tracing
+ *
+ * @param[in] cache OCF cache
+ *
+ * @retval 0 Tracing stopped successfully
+ * @retval Non-zero Error
+ */
+int ocf_mgnt_stop_trace(ocf_cache_t cache);
+
+#endif /* __OCF_TRACE_H__ */

src/engine/cache_engine.c

@@ -222,7 +222,7 @@ ocf_cache_mode_t ocf_get_effective_cache_mode(ocf_cache_t cache,
 		return ocf_cache_mode_pt;
 
 	mode = ocf_part_get_cache_mode(cache,
-			ocf_part_class2id(cache, io->class));
+			ocf_part_class2id(cache, io->io_class));
 	if (!ocf_cache_mode_is_valid(mode))
 		mode = cache->conf_meta->cache_mode;
 

src/ocf_cache_priv.h

@@ -17,10 +17,24 @@
 #include "ocf_stats_priv.h"
 #include "cleaning/cleaning.h"
 #include "ocf_logger_priv.h"
+#include "ocf/ocf_trace.h"
 
 #define DIRTY_FLUSHED 1
 #define DIRTY_NOT_FLUSHED 0
 
+/**
+ * @brief Structure used for aggregating trace-related ocf_cache fields
+ */
+struct ocf_trace {
+	/* Placeholder for push_event callback */
+	volatile ocf_trace_callback_t trace_callback;
+
+	/* Telemetry context */
+	volatile void *trace_ctx;
+
+	env_atomic64 trace_seq_ref;
+};
+
 struct ocf_metadata_uuid {
 	uint32_t size;
 	uint8_t data[OCF_DATA_OBJ_UUID_MAX_SIZE];
@@ -208,6 +222,8 @@ struct ocf_cache {
 	bool use_submit_io_fast;
 
 	void *cleaning_policy_context;
+
+	struct ocf_trace trace;
 };
 
 #define ocf_cache_log_prefix(cache, lvl, prefix, fmt, ...) \

src/ocf_core.c

@@ -13,6 +13,7 @@
 #include "utils/utils_part.h"
 #include "utils/utils_device.h"
 #include "ocf_request.h"
+#include "ocf_trace_priv.h"
 
 struct ocf_core_dobj {
 	ocf_core_t core;
@@ -287,7 +288,7 @@ static inline int ocf_core_validate_io(struct ocf_io *io)
 	if (io->addr + io->bytes > ocf_dobj_get_length(io->obj))
 		return -EINVAL;
 
-	if (io->class >= OCF_IO_CLASS_MAX)
+	if (io->io_class >= OCF_IO_CLASS_MAX)
 		return -EINVAL;
 
 	if (io->dir != OCF_READ && io->dir != OCF_WRITE)
@@ -304,6 +305,9 @@ static inline int ocf_core_validate_io(struct ocf_io *io)
 
 static void ocf_req_complete(struct ocf_request *req, int error)
 {
+	/* Log trace */
+	ocf_trace_io_cmpl(ocf_io_to_core_io(req->io), req->cache);
+
 	/* Complete IO */
 	ocf_io_end(req->io, error);
 
@@ -335,6 +339,8 @@ void ocf_core_submit_io_mode(struct ocf_io *io, ocf_cache_mode_t cache_mode)
 	core = ocf_data_obj_to_core(io->obj);
 	cache = ocf_core_get_cache(core);
 
+	ocf_trace_init_io(core_io, cache);
+
 	if (unlikely(!env_bit_test(ocf_cache_state_running,
 					&cache->cache_state))) {
 		ocf_io_end(io, -EIO);
@@ -358,9 +364,6 @@ void ocf_core_submit_io_mode(struct ocf_io *io, ocf_cache_mode_t cache_mode)
 			dec_counter_if_req_was_dirty(core_io, cache);
 	}
 
-	if (cache->conf_meta->valid_parts_no <= 1)
-		io->class = 0;
-
 	core_io->req = ocf_req_new(cache, ocf_core_get_id(core),
 			io->addr, io->bytes, io->dir);
 	if (!core_io->req) {
@@ -373,7 +376,7 @@ void ocf_core_submit_io_mode(struct ocf_io *io, ocf_cache_mode_t cache_mode)
 		req_cache_mode = ocf_req_cache_mode_d2c;
 
 	core_io->req->io_queue = io->io_queue;
-	core_io->req->part_id = ocf_part_class2id(cache, io->class);
+	core_io->req->part_id = ocf_part_class2id(cache, io->io_class);
 	core_io->req->data = core_io->data;
 	core_io->req->complete = ocf_req_complete;
 	core_io->req->io = io;
@@ -382,6 +385,11 @@ void ocf_core_submit_io_mode(struct ocf_io *io, ocf_cache_mode_t cache_mode)
 
 	ocf_core_update_stats(core, io);
 
+	if (io->dir == OCF_WRITE)
+		ocf_trace_io(core_io, ocf_event_operation_wr, cache);
+	else if (io->dir == OCF_READ)
+		ocf_trace_io(core_io, ocf_event_operation_rd, cache);
+
 	ocf_io_get(io);
 	ret = ocf_engine_hndl_req(core_io->req, req_cache_mode);
 	if (ret) {
@@ -395,6 +403,7 @@ int ocf_core_submit_io_fast(struct ocf_io *io)
 {
 	struct ocf_core_io *core_io;
 	ocf_req_cache_mode_t req_cache_mode;
+	struct ocf_event_io trace_event;
 	struct ocf_request *req;
 	ocf_core_t core;
 	ocf_cache_t cache;
@@ -444,9 +453,6 @@ int ocf_core_submit_io_fast(struct ocf_io *io)
 		req_cache_mode = ocf_req_cache_mode_fast;
 	}
 
-	if (cache->conf_meta->valid_parts_no <= 1)
-		io->class = 0;
-
 	core_io->req = ocf_req_new_extended(cache, ocf_core_get_id(core),
 			io->addr, io->bytes, io->dir);
 	// We need additional pointer to req in case completion arrives before
@@ -465,16 +471,26 @@ int ocf_core_submit_io_fast(struct ocf_io *io)
 	}
 
 	req->io_queue = io->io_queue;
-	req->part_id = ocf_part_class2id(cache, io->class);
+	req->part_id = ocf_part_class2id(cache, io->io_class);
 	req->data = core_io->data;
 	req->complete = ocf_req_complete;
 	req->io = io;
 
 	ocf_core_update_stats(core, io);
+
+	if (cache->trace.trace_callback) {
+		if (io->dir == OCF_WRITE)
+			ocf_trace_prep_io_event(&trace_event, core_io, ocf_event_operation_wr);
+		else if (io->dir == OCF_READ)
+			ocf_trace_prep_io_event(&trace_event, core_io, ocf_event_operation_rd);
+	}
+
 	ocf_io_get(io);
 
 	fast = ocf_engine_hndl_fast_req(req, req_cache_mode);
 	if (fast != OCF_FAST_PATH_NO) {
+		ocf_trace_push(cache, core_io->req->io_queue,
+				&trace_event, sizeof(trace_event));
 		ocf_seq_cutoff_update(core, req);
 		return 0;
 	}
@@ -529,6 +545,7 @@ static void ocf_core_data_obj_submit_flush(struct ocf_io *io)
 	core_io->req->io = io;
 	core_io->req->data = core_io->data;
 
+	ocf_trace_io(core_io, ocf_event_operation_flush, cache);
 	ocf_io_get(io);
 	ocf_engine_hndl_ops_req(core_io->req);
 }
@@ -571,6 +588,7 @@ static void ocf_core_data_obj_submit_discard(struct ocf_io *io)
 	core_io->req->io = io;
 	core_io->req->data = core_io->data;
 
+	ocf_trace_io(core_io, ocf_event_operation_discard, cache);
 	ocf_io_get(io);
 	ocf_engine_hndl_discard_req(core_io->req);
 }

src/ocf_core_priv.h

@@ -24,6 +24,12 @@ struct ocf_core_io {
 
 	struct ocf_request *req;
 	ctx_data_t *data;
+
+	log_sid_t sid;
+	/*!< Sequence ID */
+
+	uint64_t timestamp;
+	/*!< Timestamp */
 };
 
 struct ocf_core {

src/ocf_queue_priv.h

@@ -17,6 +17,12 @@ struct ocf_queue {
 	struct list_head io_list;
 	env_spinlock io_list_lock;
 
+	/* Tracing reference counter */
+	env_atomic64 trace_ref_cntr;
+
+	/* Tracing stop request */
+	env_atomic trace_stop;
+
 	void *priv;
 };
 

src/ocf_trace.c

@@ -0,0 +1,156 @@
+/*
+ * Copyright(c) 2012-2018 Intel Corporation
+ * SPDX-License-Identifier: BSD-3-Clause-Clear
+ */
+
+#include "ocf_env.h"
+#include "ocf_priv.h"
+#include "ocf/ocf.h"
+#include "ocf/ocf_trace.h"
+#include "ocf_core_priv.h"
+#include "ocf_cache_priv.h"
+#include "ocf_trace_priv.h"
+
+struct core_trace_visitor_ctx {
+	ocf_cache_t cache;
+	uint32_t io_queue;
+};
+
+static int _ocf_core_desc(ocf_core_t core, void  *ctx)
+{
+	struct ocf_event_core_desc core_desc;
+	struct core_trace_visitor_ctx *visitor_ctx =
+			(struct core_trace_visitor_ctx *) ctx;
+	ocf_cache_t cache = visitor_ctx->cache;
+
+	ocf_event_init_hdr(&core_desc.hdr, ocf_event_type_core_desc,
+			ocf_trace_seq_id(cache), env_get_tick_ns(), sizeof(core_desc));
+	core_desc.id = ocf_core_get_id(core);
+	core_desc.core_size = ocf_dobj_get_length(
+			ocf_core_get_data_object(core));
+
+	ocf_trace_push(cache, visitor_ctx->io_queue,
+			&core_desc, sizeof(core_desc));
+
+	return 0;
+}
+
+static int _ocf_trace_cache_info(ocf_cache_t cache, uint32_t io_queue)
+{
+	struct ocf_event_cache_desc cache_desc;
+	int retval;
+	struct core_trace_visitor_ctx visitor_ctx;
+
+	ocf_event_init_hdr(&cache_desc.hdr, ocf_event_type_cache_desc,
+			ocf_trace_seq_id(cache), env_get_tick_ns(), sizeof(cache_desc));
+
+	cache_desc.id = ocf_cache_get_id(cache);
+	cache_desc.cache_line_size = ocf_cache_get_line_size(cache);
+	cache_desc.cache_mode = ocf_cache_get_mode(cache);
+
+	if (ocf_cache_is_device_attached(cache)) {
+		/* Attached cache */
+		cache_desc.cache_size = ocf_dobj_get_length(
+				ocf_cache_get_data_object(cache));
+	} else {
+		cache_desc.cache_size = 0;
+	}
+
+	cache_desc.cores_no = ocf_cache_get_core_count(cache);
+	cache_desc.version = OCF_EVENT_VERSION;
+	cache_desc.io_queues_no = cache->io_queues_no;
+
+	ocf_trace_push(cache, io_queue, &cache_desc, sizeof(cache_desc));
+
+	visitor_ctx.cache = cache;
+	visitor_ctx.io_queue = io_queue;
+
+	retval = ocf_core_visit(cache, _ocf_core_desc, &visitor_ctx, true);
+
+	return retval;
+}
+
+int ocf_mgnt_start_trace(ocf_cache_t cache, void *trace_ctx,
+	ocf_trace_callback_t trace_callback)
+{
+	int result;
+	uint32_t i;
+
+	OCF_CHECK_NULL(cache);
+
+	if (!trace_callback) {
+		return -EINVAL;
+	}
+
+	result = ocf_mngt_cache_lock(cache);
+	if (result)
+		return result;
+
+	if (cache->trace.trace_callback) {
+		ocf_cache_log(cache, log_err,
+				"Tracing already started for cache %u\n",
+				ocf_cache_get_id(cache));
+		ocf_mngt_cache_unlock(cache);
+		return -EINVAL;
+	}
+
+	cache->trace.trace_callback = trace_callback;
+	cache->trace.trace_ctx = trace_ctx;
+
+	// Reset trace stop flag
+	for (int queue = 0; queue < cache->io_queues_no; queue++) {
+		env_atomic_set(&cache->io_queues[queue].trace_stop, 0);
+	}
+
+	for (i = 0; i < cache->io_queues_no; i++) {
+		result = _ocf_trace_cache_info(cache, i);
+		if (result)
+			goto trace_deinit;
+	}
+
+	ocf_cache_log(cache, log_info,
+			"Tracing started for cache %u\n", ocf_cache_get_id(cache));
+
+	ocf_mngt_cache_unlock(cache);
+	return result;
+
+trace_deinit:
+	cache->trace.trace_callback = NULL;
+	ocf_mngt_cache_unlock(cache);
+
+	return result;
+}
+
+int ocf_mgnt_stop_trace(ocf_cache_t cache)
+{
+	int result;
+
+	result = ocf_mngt_cache_lock(cache);
+	if (result)
+		return result;
+
+	if (!cache->trace.trace_callback) {
+		ocf_cache_log(cache, log_err,
+				"Tracing not started for cache %u\n",
+				ocf_cache_get_id(cache));
+		ocf_mngt_cache_unlock(cache);
+		return -EINVAL;
+	}
+
+	// Set trace stop flag
+	for (int queue = 0; queue < cache->io_queues_no; queue++) {
+		env_atomic_set(&cache->io_queues[queue].trace_stop, OCF_TRACING_STOP);
+	}
+
+	cache->trace.trace_callback = NULL;
+	cache->trace.trace_ctx = NULL;
+
+	// Poll for all ongoing traces completion
+	while (ocf_is_trace_ongoing(cache)) {
+		env_msleep(20);
+	}
+
+	ocf_mngt_cache_unlock(cache);
+
+	return result;
+}

src/ocf_trace_priv.h

@@ -0,0 +1,130 @@
+/*
+ * Copyright(c) 2012-2018 Intel Corporation
+ * SPDX-License-Identifier: BSD-3-Clause-Clear
+ */
+
+#ifndef __OCF_TRACE_PRIV_H__
+#define __OCF_TRACE_PRIV_H__
+
+#include "ocf/ocf_trace.h"
+#include "engine/engine_common.h"
+#include "ocf_request.h"
+#include "ocf_core_priv.h"
+#include "ocf_queue_priv.h"
+
+static inline bool ocf_is_trace_ongoing(ocf_cache_t cache)
+{
+	for (int i = 0; i < cache->io_queues_no; i++) {
+		if (env_atomic64_read(&cache->io_queues[i].trace_ref_cntr)) {
+			return true;
+		}
+	}
+
+	return false;
+}
+static inline void ocf_event_init_hdr(struct ocf_event_hdr *hdr,
+		ocf_event_type type, uint64_t sid, uint64_t timestamp,
+		uint32_t size)
+{
+	hdr->sid = sid;
+	hdr->timestamp = timestamp;
+	hdr->type = type;
+	hdr->size = size;
+}
+
+static inline uint64_t ocf_trace_seq_id(ocf_cache_t cache)
+{
+	return env_atomic64_inc_return(&cache->trace.trace_seq_ref);
+}
+
+static inline void ocf_trace_init_io(struct ocf_core_io *io, ocf_cache_t cache)
+{
+	io->timestamp = env_get_tick_ns();
+	io->sid = ocf_trace_seq_id(cache);
+}
+
+static inline void ocf_trace_prep_io_event(struct ocf_event_io *ev,
+		struct ocf_core_io *io, ocf_event_operation_t op)
+{
+	struct ocf_request *rq = io->req;
+
+	ocf_event_init_hdr(&ev->hdr, ocf_event_type_io, io->sid,
+		io->timestamp, sizeof(*ev));
+
+	ev->addr = rq->byte_position;
+	if (op == ocf_event_operation_discard)
+		ev->len = rq->discard.nr_sects << ENV_SECTOR_SHIFT;
+	else
+		ev->len = rq->byte_length;
+
+	ev->operation = op;
+	ev->core_id = rq->core_id;
+
+	ev->io_class = rq->io->io_class;
+}
+
+static inline void ocf_trace_push(ocf_cache_t cache, uint32_t io_queue,
+	void *trace, uint32_t size)
+{
+	ocf_trace_callback_t trace_callback;
+	void *trace_ctx;
+
+	if (cache->trace.trace_callback == NULL)
+		return;
+
+	env_atomic64_inc(&cache->io_queues[io_queue].trace_ref_cntr);
+
+	if (env_atomic_read(&cache->io_queues[io_queue].trace_stop)) {
+		// Tracing stop was requested
+		env_atomic64_dec(&cache->io_queues[io_queue].trace_ref_cntr);
+		return;
+	}
+
+	/*
+	 * Remember callback and context pointers.
+	 * These will be valid even when later on original pointers
+	 * will be set to NULL as cleanup will wait till trace
+	 * reference counter is zero
+	 */
+	trace_callback = cache->trace.trace_callback;
+	trace_ctx = cache->trace.trace_ctx;
+
+	if (trace_callback && trace_ctx) {
+		trace_callback(cache, trace_ctx, io_queue, trace, size);
+	}
+
+	env_atomic64_dec(&cache->io_queues[io_queue].trace_ref_cntr);
+}
+
+static inline void ocf_trace_io(struct ocf_core_io *io, ocf_event_operation_t dir, ocf_cache_t cache)
+{
+	struct ocf_event_io ev;
+	struct ocf_request *rq;
+
+	if (!cache->trace.trace_callback)
+		return;
+
+	rq  = io->req;
+	ocf_trace_prep_io_event(&ev, io, dir);
+
+	ocf_trace_push(cache, rq->io_queue, &ev, sizeof(ev));
+}
+
+static inline void ocf_trace_io_cmpl(struct ocf_core_io *io, ocf_cache_t cache)
+{
+	struct ocf_event_io_cmpl ev;
+	struct ocf_request *rq;
+
+	if (!cache->trace.trace_callback)
+		return;
+
+	rq = io->req;
+	ocf_event_init_hdr(&ev.hdr, ocf_event_type_io_cmpl,
+		ocf_trace_seq_id(cache), env_get_tick_ns(), sizeof(ev));
+	ev.rsid = io->sid;
+	ev.is_hit = ocf_engine_is_hit(rq);
+
+	ocf_trace_push(cache, rq->io_queue, &ev, sizeof(ev));
+}
+
+#endif /* __OCF_TRACE_PRIV_H__ */

src/utils/utils_io.c

@@ -217,7 +217,7 @@ void ocf_submit_cache_reqs(struct ocf_cache *cache,
 {
 	struct ocf_counters_block *cache_stats;
 	uint64_t flags = req->io ? req->io->flags : 0;
-	uint32_t class = req->io ? req->io->class : 0;
+	uint32_t class = req->io ? req->io->io_class : 0;
 	uint64_t addr, bytes, total_bytes = 0;
 	struct ocf_io *io;
 	uint32_t i;
@@ -317,7 +317,7 @@ void ocf_submit_obj_req(ocf_data_obj_t obj, struct ocf_request *req,
 	struct ocf_cache *cache = req->cache;
 	struct ocf_counters_block *core_stats;
 	uint64_t flags = req->io ? req->io->flags : 0;
-	uint32_t class = req->io ? req->io->class : 0;
+	uint32_t class = req->io ? req->io->io_class : 0;
 	int dir = req->rw;
 	struct ocf_io *io;
 	int err;