mempool: support block dequeue operation

If mempool manager supports object blocks (physically and virtual
contiguous set of objects), it is sufficient to get the first
object only and the function allows to avoid filling in of
information about each block member.

Signed-off-by: Artem V. Andreev <artem.andreev@oktetlabs.ru>
Signed-off-by: Andrew Rybchenko <arybchenko@solarflare.com>
Acked-by: Olivier Matz <olivier.matz@6wind.com>

doc/guides/rel_notes/deprecation.rst

@@ -37,13 +37,6 @@ Deprecation Notices
 
   - ``rte_eal_mbuf_default_mempool_ops``
 
-* mempool: several API and ABI changes are planned in v18.05.
-
-  The following changes are planned:
-
-  - addition of new op to allocate contiguous
-    block of objects if underlying driver supports it.
-
 * mbuf: The opaque ``mbuf->hash.sched`` field will be updated to support generic
   definition in line with the ethdev TM and MTR APIs. Currently, this field
   is defined in librte_sched in a non-generic way. The new generic format

lib/librte_mempool/Makefile

@@ -10,6 +10,7 @@ CFLAGS += $(WERROR_FLAGS) -I$(SRCDIR) -O3
 # Allow deprecated symbol to use deprecated rte_mempool_populate_iova_tab()
 # from earlier deprecated rte_mempool_populate_phys_tab()
 CFLAGS += -Wno-deprecated-declarations
+CFLAGS += -DALLOW_EXPERIMENTAL_API
 LDLIBS += -lrte_eal -lrte_ring
 
 EXPORT_MAP := rte_mempool_version.map

lib/librte_mempool/meson.build

@@ -1,6 +1,8 @@
 # SPDX-License-Identifier: BSD-3-Clause
 # Copyright(c) 2017 Intel Corporation
 
+allow_experimental_apis = true
+
 extra_flags = []
 
 # Allow deprecated symbol to use deprecated rte_mempool_populate_iova_tab()

lib/librte_mempool/rte_mempool.c

@@ -1255,6 +1255,36 @@ void rte_mempool_check_cookies(const struct rte_mempool *mp,
 #endif
 }
 
+void
+rte_mempool_contig_blocks_check_cookies(const struct rte_mempool *mp,
+	void * const *first_obj_table_const, unsigned int n, int free)
+{
+#ifdef RTE_LIBRTE_MEMPOOL_DEBUG
+	struct rte_mempool_info info;
+	const size_t total_elt_sz =
+		mp->header_size + mp->elt_size + mp->trailer_size;
+	unsigned int i, j;
+
+	rte_mempool_ops_get_info(mp, &info);
+
+	for (i = 0; i < n; ++i) {
+		void *first_obj = first_obj_table_const[i];
+
+		for (j = 0; j < info.contig_block_size; ++j) {
+			void *obj;
+
+			obj = (void *)((uintptr_t)first_obj + j * total_elt_sz);
+			rte_mempool_check_cookies(mp, &obj, 1, free);
+		}
+	}
+#else
+	RTE_SET_USED(mp);
+	RTE_SET_USED(first_obj_table_const);
+	RTE_SET_USED(n);
+	RTE_SET_USED(free);
+#endif
+}
+
 #ifdef RTE_LIBRTE_MEMPOOL_DEBUG
 static void
 mempool_obj_audit(struct rte_mempool *mp, __rte_unused void *opaque,
@@ -1320,6 +1350,7 @@ void
 rte_mempool_dump(FILE *f, struct rte_mempool *mp)
 {
 #ifdef RTE_LIBRTE_MEMPOOL_DEBUG
+	struct rte_mempool_info info;
 	struct rte_mempool_debug_stats sum;
 	unsigned lcore_id;
 #endif
@@ -1361,6 +1392,7 @@ rte_mempool_dump(FILE *f, struct rte_mempool *mp)
 
 	/* sum and dump statistics */
 #ifdef RTE_LIBRTE_MEMPOOL_DEBUG
+	rte_mempool_ops_get_info(mp, &info);
 	memset(&sum, 0, sizeof(sum));
 	for (lcore_id = 0; lcore_id < RTE_MAX_LCORE; lcore_id++) {
 		sum.put_bulk += mp->stats[lcore_id].put_bulk;
@@ -1369,6 +1401,8 @@ rte_mempool_dump(FILE *f, struct rte_mempool *mp)
 		sum.get_success_objs += mp->stats[lcore_id].get_success_objs;
 		sum.get_fail_bulk += mp->stats[lcore_id].get_fail_bulk;
 		sum.get_fail_objs += mp->stats[lcore_id].get_fail_objs;
+		sum.get_success_blks += mp->stats[lcore_id].get_success_blks;
+		sum.get_fail_blks += mp->stats[lcore_id].get_fail_blks;
 	}
 	fprintf(f, "  stats:\n");
 	fprintf(f, "    put_bulk=%"PRIu64"\n", sum.put_bulk);
@@ -1377,6 +1411,11 @@ rte_mempool_dump(FILE *f, struct rte_mempool *mp)
 	fprintf(f, "    get_success_objs=%"PRIu64"\n", sum.get_success_objs);
 	fprintf(f, "    get_fail_bulk=%"PRIu64"\n", sum.get_fail_bulk);
 	fprintf(f, "    get_fail_objs=%"PRIu64"\n", sum.get_fail_objs);
+	if (info.contig_block_size > 0) {
+		fprintf(f, "    get_success_blks=%"PRIu64"\n",
+			sum.get_success_blks);
+		fprintf(f, "    get_fail_blks=%"PRIu64"\n", sum.get_fail_blks);
+	}
 #else
 	fprintf(f, "  no statistics available\n");
 #endif

lib/librte_mempool/rte_mempool.h

@@ -70,6 +70,10 @@ struct rte_mempool_debug_stats {
 	uint64_t get_success_objs; /**< Objects successfully allocated. */
 	uint64_t get_fail_bulk;    /**< Failed allocation number. */
 	uint64_t get_fail_objs;    /**< Objects that failed to be allocated. */
+	/** Successful allocation number of contiguous blocks. */
+	uint64_t get_success_blks;
+	/** Failed allocation number of contiguous blocks. */
+	uint64_t get_fail_blks;
 } __rte_cache_aligned;
 #endif
 
@@ -199,11 +203,8 @@ struct rte_mempool_memhdr {
  * a number of cases when something small is added.
  */
 struct rte_mempool_info {
-	/*
-	 * Dummy structure member to make it non emtpy until the first
-	 * real member is added.
-	 */
-	unsigned int dummy;
+	/** Number of objects in the contiguous block */
+	unsigned int contig_block_size;
 } __rte_cache_aligned;
 
 /**
@@ -282,8 +283,16 @@ struct rte_mempool {
 			mp->stats[__lcore_id].name##_bulk += 1;	\
 		}                                               \
 	} while(0)
+#define __MEMPOOL_CONTIG_BLOCKS_STAT_ADD(mp, name, n) do {                    \
+		unsigned int __lcore_id = rte_lcore_id();       \
+		if (__lcore_id < RTE_MAX_LCORE) {               \
+			mp->stats[__lcore_id].name##_blks += n;	\
+			mp->stats[__lcore_id].name##_bulk += 1;	\
+		}                                               \
+	} while (0)
 #else
 #define __MEMPOOL_STAT_ADD(mp, name, n) do {} while(0)
+#define __MEMPOOL_CONTIG_BLOCKS_STAT_ADD(mp, name, n) do {} while (0)
 #endif
 
 /**
@@ -351,6 +360,38 @@ void rte_mempool_check_cookies(const struct rte_mempool *mp,
 #define __mempool_check_cookies(mp, obj_table_const, n, free) do {} while(0)
 #endif /* RTE_LIBRTE_MEMPOOL_DEBUG */
 
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * @internal Check contiguous object blocks and update cookies or panic.
+ *
+ * @param mp
+ *   Pointer to the memory pool.
+ * @param first_obj_table_const
+ *   Pointer to a table of void * pointers (first object of the contiguous
+ *   object blocks).
+ * @param n
+ *   Number of contiguous object blocks.
+ * @param free
+ *   - 0: object is supposed to be allocated, mark it as free
+ *   - 1: object is supposed to be free, mark it as allocated
+ *   - 2: just check that cookie is valid (free or allocated)
+ */
+void rte_mempool_contig_blocks_check_cookies(const struct rte_mempool *mp,
+	void * const *first_obj_table_const, unsigned int n, int free);
+
+#ifdef RTE_LIBRTE_MEMPOOL_DEBUG
+#define __mempool_contig_blocks_check_cookies(mp, first_obj_table_const, n, \
+					      free) \
+	rte_mempool_contig_blocks_check_cookies(mp, first_obj_table_const, n, \
+						free)
+#else
+#define __mempool_contig_blocks_check_cookies(mp, first_obj_table_const, n, \
+					      free) \
+	do {} while (0)
+#endif /* RTE_LIBRTE_MEMPOOL_DEBUG */
+
 #define RTE_MEMPOOL_OPS_NAMESIZE 32 /**< Max length of ops struct name. */
 
 /**
@@ -382,6 +423,15 @@ typedef int (*rte_mempool_enqueue_t)(struct rte_mempool *mp,
 typedef int (*rte_mempool_dequeue_t)(struct rte_mempool *mp,
 		void **obj_table, unsigned int n);
 
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * Dequeue a number of contiquous object blocks from the external pool.
+ */
+typedef int (*rte_mempool_dequeue_contig_blocks_t)(struct rte_mempool *mp,
+		 void **first_obj_table, unsigned int n);
+
 /**
  * Return the number of available objects in the external pool.
  */
@@ -548,6 +598,10 @@ struct rte_mempool_ops {
 	 * Get mempool info
 	 */
 	rte_mempool_get_info_t get_info;
+	/**
+	 * Dequeue a number of contiguous object blocks.
+	 */
+	rte_mempool_dequeue_contig_blocks_t dequeue_contig_blocks;
 } __rte_cache_aligned;
 
 #define RTE_MEMPOOL_MAX_OPS_IDX 16  /**< Max registered ops structs */
@@ -625,6 +679,30 @@ rte_mempool_ops_dequeue_bulk(struct rte_mempool *mp,
 	return ops->dequeue(mp, obj_table, n);
 }
 
+/**
+ * @internal Wrapper for mempool_ops dequeue_contig_blocks callback.
+ *
+ * @param[in] mp
+ *   Pointer to the memory pool.
+ * @param[out] first_obj_table
+ *   Pointer to a table of void * pointers (first objects).
+ * @param[in] n
+ *   Number of blocks to get.
+ * @return
+ *   - 0: Success; got n objects.
+ *   - <0: Error; code of dequeue function.
+ */
+static inline int
+rte_mempool_ops_dequeue_contig_blocks(struct rte_mempool *mp,
+		void **first_obj_table, unsigned int n)
+{
+	struct rte_mempool_ops *ops;
+
+	ops = rte_mempool_get_ops(mp->ops_index);
+	RTE_ASSERT(ops->dequeue_contig_blocks != NULL);
+	return ops->dequeue_contig_blocks(mp, first_obj_table, n);
+}
+
 /**
  * @internal wrapper for mempool_ops enqueue callback.
  *
@@ -1539,6 +1617,49 @@ rte_mempool_get(struct rte_mempool *mp, void **obj_p)
 	return rte_mempool_get_bulk(mp, obj_p, 1);
 }
 
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * Get a contiguous blocks of objects from the mempool.
+ *
+ * If cache is enabled, consider to flush it first, to reuse objects
+ * as soon as possible.
+ *
+ * The application should check that the driver supports the operation
+ * by calling rte_mempool_ops_get_info() and checking that `contig_block_size`
+ * is not zero.
+ *
+ * @param mp
+ *   A pointer to the mempool structure.
+ * @param first_obj_table
+ *   A pointer to a pointer to the first object in each block.
+ * @param n
+ *   The number of blocks to get from mempool.
+ * @return
+ *   - 0: Success; blocks taken.
+ *   - -ENOBUFS: Not enough entries in the mempool; no object is retrieved.
+ *   - -EOPNOTSUPP: The mempool driver does not support block dequeue
+ */
+static __rte_always_inline int
+__rte_experimental
+rte_mempool_get_contig_blocks(struct rte_mempool *mp,
+			      void **first_obj_table, unsigned int n)
+{
+	int ret;
+
+	ret = rte_mempool_ops_dequeue_contig_blocks(mp, first_obj_table, n);
+	if (ret == 0) {
+		__MEMPOOL_CONTIG_BLOCKS_STAT_ADD(mp, get_success, n);
+		__mempool_contig_blocks_check_cookies(mp, first_obj_table, n,
+						      1);
+	} else {
+		__MEMPOOL_CONTIG_BLOCKS_STAT_ADD(mp, get_fail, n);
+	}
+
+	return ret;
+}
+
 /**
  * Return the number of entries in the mempool.
  *

lib/librte_mempool/rte_mempool_ops.c

@@ -60,6 +60,7 @@ rte_mempool_register_ops(const struct rte_mempool_ops *h)
 	ops->calc_mem_size = h->calc_mem_size;
 	ops->populate = h->populate;
 	ops->get_info = h->get_info;
+	ops->dequeue_contig_blocks = h->dequeue_contig_blocks;
 
 	rte_spinlock_unlock(&rte_mempool_ops_table.sl);
 

lib/librte_mempool/rte_mempool_version.map

@@ -53,6 +53,7 @@ DPDK_17.11 {
 DPDK_18.05 {
 	global:
 
+	rte_mempool_contig_blocks_check_cookies;
 	rte_mempool_op_calc_mem_size_default;
 	rte_mempool_op_populate_default;