[dpdk-dev] [RFC v2 04/17] mempool: add op to populate objects using provided memory

[Andrew Rybchenko <arybchenko@solarflare.com>]

The callback allows to customize how objects are stored in the
memory chunk. Default implementation of the callback which simply
puts objects one by one is available.

Suggested-by: Olivier Matz <olivier.matz@6wind.com>
Signed-off-by: Andrew Rybchenko <arybchenko@solarflare.com>
---
 lib/librte_mempool/rte_mempool.c           | 44 +++++++++++-----
 lib/librte_mempool/rte_mempool.h           | 83 ++++++++++++++++++++++++++++++
 lib/librte_mempool/rte_mempool_ops.c       | 18 +++++++
 lib/librte_mempool/rte_mempool_version.map |  1 +
 4 files changed, 133 insertions(+), 13 deletions(-)

diff --git a/lib/librte_mempool/rte_mempool.c b/lib/librte_mempool/rte_mempool.c
index 1f54f95..c5003a9 100644
--- a/lib/librte_mempool/rte_mempool.c
+++ b/lib/librte_mempool/rte_mempool.c
@@ -145,9 +145,6 @@ mempool_add_elem(struct rte_mempool *mp, void *obj, rte_iova_t iova)
 	tlr = __mempool_get_trailer(obj);
 	tlr->cookie = RTE_MEMPOOL_TRAILER_COOKIE;
 #endif
-
-	/* enqueue in ring */
-	rte_mempool_ops_enqueue_bulk(mp, &obj, 1);
 }
 
 /* call obj_cb() for each mempool element */
@@ -396,6 +393,30 @@ rte_mempool_free_memchunks(struct rte_mempool *mp)
 	}
 }
 
+int
+rte_mempool_populate_one_by_one(struct rte_mempool *mp, unsigned int max_objs,
+		void *vaddr, rte_iova_t iova, size_t len,
+		rte_mempool_populate_obj_cb_t *obj_cb)
+{
+	size_t total_elt_sz;
+	size_t off;
+	unsigned int i;
+	void *obj;
+
+	total_elt_sz = mp->header_size + mp->elt_size + mp->trailer_size;
+
+	for (off = 0, i = 0; off + total_elt_sz <= len && i < max_objs; i++) {
+		off += mp->header_size;
+		obj = (char *)vaddr + off;
+		obj_cb(mp, obj,
+		       (iova == RTE_BAD_IOVA) ? RTE_BAD_IOVA : (iova + off));
+		rte_mempool_ops_enqueue_bulk(mp, &obj, 1);
+		off += mp->elt_size + mp->trailer_size;
+	}
+
+	return i;
+}
+
 /* Add objects in the pool, using a physically contiguous memory
  * zone. Return the number of objects added, or a negative value
  * on error.
@@ -466,16 +487,13 @@ rte_mempool_populate_iova(struct rte_mempool *mp, char *vaddr,
 	else
 		off = RTE_PTR_ALIGN_CEIL(vaddr, RTE_CACHE_LINE_SIZE) - vaddr;
 
-	while (off + total_elt_sz <= len && mp->populated_size < mp->size) {
-		off += mp->header_size;
-		if (iova == RTE_BAD_IOVA)
-			mempool_add_elem(mp, (char *)vaddr + off,
-				RTE_BAD_IOVA);
-		else
-			mempool_add_elem(mp, (char *)vaddr + off, iova + off);
-		off += mp->elt_size + mp->trailer_size;
-		i++;
-	}
+	if (off > len)
+		return -EINVAL;
+
+	i = rte_mempool_ops_populate(mp, mp->size - mp->populated_size,
+		(char *)vaddr + off,
+		(iova == RTE_BAD_IOVA) ? RTE_BAD_IOVA : (iova + off),
+		len - off, mempool_add_elem);
 
 	/* not enough room to store one object */
 	if (i == 0)
diff --git a/lib/librte_mempool/rte_mempool.h b/lib/librte_mempool/rte_mempool.h
index be8a371..f6ffab9 100644
--- a/lib/librte_mempool/rte_mempool.h
+++ b/lib/librte_mempool/rte_mempool.h
@@ -461,6 +461,59 @@ ssize_t rte_mempool_calc_mem_size_def(const struct rte_mempool *mp,
 				      uint32_t obj_num, uint32_t pg_shift,
 				      size_t *min_chunk_size, size_t *align);
 
+/**
+ * Function to be called for each populated object.
+ *
+ * @param mp
+ *   A pointer to the mempool structure.
+ * @param vaddr
+ *   Object virtual address.
+ * @param iova
+ *   Input/output virtual addresss of the object or #RTE_BAD_IOVA.
+ */
+typedef void (rte_mempool_populate_obj_cb_t)(struct rte_mempool *mp,
+		void *vaddr, rte_iova_t iova);
+
+/**
+ * Populate memory pool objects using provided memory chunk.
+ *
+ * Populated objects should be enqueued to the pool, e.g. using
+ * rte_mempool_ops_enqueue_bulk().
+ *
+ * If the given IO address is unknown (iova = RTE_BAD_IOVA),
+ * the chunk doesn't need to be physically contiguous (only virtually),
+ * and allocated objects may span two pages.
+ *
+ * @param mp
+ *   A pointer to the mempool structure.
+ * @param max_objs
+ *   Maximum number of objects to be populated.
+ * @param vaddr
+ *   The virtual address of memory that should be used to store objects.
+ * @param iova
+ *   The IO address
+ * @param len
+ *   The length of memory in bytes.
+ * @param obj_cb
+ *   Callback function to be executed for each populated object.
+ * @return
+ *   The number of objects added on success.
+ *   On error, no objects are populated and a negative errno is returned.
+ */
+typedef int (*rte_mempool_populate_t)(struct rte_mempool *mp,
+		unsigned int max_objs,
+		void *vaddr, rte_iova_t iova, size_t len,
+		rte_mempool_populate_obj_cb_t *obj_cb);
+
+/**
+ * Default way to populate memory pool object using provided memory
+ * chunk: just slice objects one by one.
+ */
+int rte_mempool_populate_one_by_one(struct rte_mempool *mp,
+		unsigned int max_objs,
+		void *vaddr, rte_iova_t iova, size_t len,
+		rte_mempool_populate_obj_cb_t *obj_cb);
+
 /** Structure defining mempool operations structure */
 struct rte_mempool_ops {
 	char name[RTE_MEMPOOL_OPS_NAMESIZE]; /**< Name of mempool ops struct. */
@@ -482,6 +535,11 @@ struct rte_mempool_ops {
 	 * store specified number of objects.
 	 */
 	rte_mempool_calc_mem_size_t calc_mem_size;
+	/**
+	 * Optional callback to populate mempool objects using
+	 * provided memory chunk.
+	 */
+	rte_mempool_populate_t populate;
 } __rte_cache_aligned;
 
 #define RTE_MEMPOOL_MAX_OPS_IDX 16  /**< Max registered ops structs */
@@ -654,6 +712,31 @@ ssize_t rte_mempool_ops_calc_mem_size(const struct rte_mempool *mp,
 				      size_t *min_chunk_size, size_t *align);
 
 /**
+ * @internal wrapper for mempool_ops populate callback.
+ *
+ * Populate memory pool objects using provided memory chunk.
+ *
+ * @param mp
+ *   A pointer to the mempool structure.
+ * @param max_objs
+ *   Maximum number of objects to be populated.
+ * @param vaddr
+ *   The virtual address of memory that should be used to store objects.
+ * @param iova
+ *   The IO address
+ * @param len
+ *   The length of memory in bytes.
+ * @param obj_cb
+ *   Callback function to be executed for each populated object.
+ * @return
+ *   The number of objects added on success.
+ *   On error, no objects are populated and a negative errno is returned.
+ */
+int rte_mempool_ops_populate(struct rte_mempool *mp, unsigned int max_objs,
+			     void *vaddr, rte_iova_t iova, size_t len,
+			     rte_mempool_populate_obj_cb_t *obj_cb);
+
+/**
  * @internal wrapper for mempool_ops free callback.
  *
  * @param mp
diff --git a/lib/librte_mempool/rte_mempool_ops.c b/lib/librte_mempool/rte_mempool_ops.c
index d048b37..7c4a22b 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->calc_mem_size = h->calc_mem_size;
+	ops->populate = h->populate;
 
 	rte_spinlock_unlock(&rte_mempool_ops_table.sl);
 
@@ -170,6 +171,23 @@ rte_mempool_ops_calc_mem_size(const struct rte_mempool *mp,
 	return ops->calc_mem_size(mp, obj_num, pg_shift, min_chunk_size, align);
 }
 
+/* wrapper to populate memory pool objects using provided memory chunk */
+int
+rte_mempool_ops_populate(struct rte_mempool *mp, unsigned int max_objs,
+				void *vaddr, rte_iova_t iova, size_t len,
+				rte_mempool_populate_obj_cb_t *obj_cb)
+{
+	struct rte_mempool_ops *ops;
+
+	ops = rte_mempool_get_ops(mp->ops_index);
+
+	if (ops->populate == NULL)
+		return rte_mempool_populate_one_by_one(mp, max_objs, vaddr,
+						       iova, len, obj_cb);
+
+	return ops->populate(mp, max_objs, vaddr, iova, len, obj_cb);
+}
+
 /* sets mempool ops previously registered by rte_mempool_register_ops. */
 int
 rte_mempool_set_ops_byname(struct rte_mempool *mp, const char *name,
diff --git a/lib/librte_mempool/rte_mempool_version.map b/lib/librte_mempool/rte_mempool_version.map
index 9fa7270..00288de 100644
--- a/lib/librte_mempool/rte_mempool_version.map
+++ b/lib/librte_mempool/rte_mempool_version.map
@@ -56,6 +56,7 @@ DPDK_18.05 {
 	global:
 
 	rte_mempool_calc_mem_size_def;
+	rte_mempool_populate_one_by_one;
 
 } DPDK_17.11;
 
-- 
2.7.4