[dpdk-dev] [RFC PATCH 5/6] mempool: support block dequeue operation

[Andrew Rybchenko <arybchenko@solarflare.com>]

From: "Artem V. Andreev" <Artem.Andreev@oktetlabs.ru>

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>
---
 lib/librte_mempool/rte_mempool.c     |   4 +-
 lib/librte_mempool/rte_mempool.h     | 111 +++++++++++++++++++++++++++++++++++
 lib/librte_mempool/rte_mempool_ops.c |   1 +
 3 files changed, 115 insertions(+), 1 deletion(-)

diff --git a/lib/librte_mempool/rte_mempool.c b/lib/librte_mempool/rte_mempool.c
index 43455a3..6850d6e 100644
--- a/lib/librte_mempool/rte_mempool.c
+++ b/lib/librte_mempool/rte_mempool.c
@@ -603,8 +603,10 @@ rte_mempool_populate_default(struct rte_mempool *mp)
 	ret = rte_mempool_ops_get_info(mp, &mp->info);
 	if ((ret < 0) && (ret != -ENOTSUP))
 		return ret;
-	if (ret == -ENOTSUP)
+	if (ret == -ENOTSUP) {
 		mp->info.cluster_size = 0;
+		mp->info.contig_block_size = 0;
+	}
 
 	if ((mp->info.cluster_size == 0) &&
 	    (mp_flags & MEMPOOL_F_CAPA_ALLOCATE_IN_CLUSTERS))
diff --git a/lib/librte_mempool/rte_mempool.h b/lib/librte_mempool/rte_mempool.h
index 3a52b93..4575eb2 100644
--- a/lib/librte_mempool/rte_mempool.h
+++ b/lib/librte_mempool/rte_mempool.h
@@ -223,6 +223,8 @@ struct rte_mempool_memhdr {
 struct rte_mempool_info {
 	/** Number of objects in a cluster */
 	unsigned int cluster_size;
+	/** Number of objects in the contiguous block */
+	unsigned int contig_block_size;
 };
 
 /**
@@ -431,6 +433,12 @@ typedef int (*rte_mempool_dequeue_t)(struct rte_mempool *mp,
 		void **obj_table, unsigned int n);
 
 /**
+ * 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.
  */
 typedef unsigned (*rte_mempool_get_count)(const struct rte_mempool *mp);
@@ -473,6 +481,10 @@ 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 */
@@ -551,6 +563,30 @@ rte_mempool_ops_dequeue_bulk(struct rte_mempool *mp,
 }
 
 /**
+ * @internal Wrapper for mempool_ops dequeue_contig_blocks callback.
+ *
+ * @param mp
+ *   Pointer to the memory pool.
+ * @param first_obj_table
+ *   Pointer to a table of void * pointers (first objects).
+ * @param 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.
  *
  * @param mp
@@ -1456,6 +1492,81 @@ rte_mempool_get(struct rte_mempool *mp, void **obj_p)
 }
 
 /**
+ * @internal Get contiguous blocks of objects from the pool. Used internally.
+ * @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
+ *   A number of blocks to get.
+ * @return
+ *   - >0: Success
+ *   - <0: Error
+ */
+static __rte_always_inline int
+__mempool_generic_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_STAT_ADD(mp, get_fail,
+				   n * mp->info.contig_block_size);
+	else
+		__MEMPOOL_STAT_ADD(mp, get_success,
+				   n * mp->info.contig_block_size);
+
+	return ret;
+}
+
+/**
+ * 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.
+ *
+ * @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: the size of the block
+ *   - -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_mempool_get_contig_blocks(struct rte_mempool *mp,
+			      void **first_obj_table, unsigned int n)
+{
+	int ret;
+
+	ret = __mempool_generic_get_contig_blocks(mp, first_obj_table, n);
+#ifdef RTE_LIBRTE_MEMPOOL_DEBUG
+	if (ret == 0) {
+		const size_t total_elt_sz =
+			mp->header_size + mp->elt_size + mp->trailer_size;
+		unsigned int i, j;
+
+		for (i = 0; i < n; ++i) {
+			void *first_obj = first_obj_table[i];
+
+			for (j = 0; j < mp->info.contig_block_size; ++j) {
+				void *obj;
+
+				obj = (void *)((uintptr_t)first_obj +
+					       j * total_elt_sz);
+				rte_mempool_check_cookies(mp, &obj, 1, 1);
+			}
+		}
+	}
+#endif
+	return ret;
+}
+
+/**
  * Return the number of entries in the mempool.
  *
  * When cache is enabled, this function has to browse the length of
diff --git a/lib/librte_mempool/rte_mempool_ops.c b/lib/librte_mempool/rte_mempool_ops.c
index 23de4db..cc38761 100644
--- a/lib/librte_mempool/rte_mempool_ops.c
+++ b/lib/librte_mempool/rte_mempool_ops.c
@@ -89,6 +89,7 @@ rte_mempool_register_ops(const struct rte_mempool_ops *h)
 	ops->get_capabilities = h->get_capabilities;
 	ops->register_memory_area = h->register_memory_area;
 	ops->get_info = h->get_info;
+	ops->dequeue_contig_blocks = h->dequeue_contig_blocks;
 
 	rte_spinlock_unlock(&rte_mempool_ops_table.sl);
 
-- 
2.7.4