[PATCH v15 2/6] mempool: add functions to get extra mempool info

[Paul Szczepanek]

Add two functions:
- rte_mempool_get_mem_range - get virtual memory range
of the objects in the mempool,
- rte_mempool_get_obj_alignment - get alignment of
objects in the mempool.

Add two tests that test these new functions.

Signed-off-by: Paul Szczepanek <paul.szczepanek at arm.com>
Reviewed-by: Jack Bond-Preston <jack.bond-preston at foss.arm.com>
Reviewed-by: Nathan Brown <nathan.brown at arm.com>
Acked-by: Morten Brørup <mb at smartsharesystems.com>
Acked-by: Konstantin Ananyev <konstantin.v.ananyev at yandex.ru>
---
 app/test/test_mempool.c   | 70 +++++++++++++++++++++++++++++++++++++++
 lib/mempool/rte_mempool.c | 45 +++++++++++++++++++++++++
 lib/mempool/rte_mempool.h | 49 +++++++++++++++++++++++++++
 lib/mempool/version.map   |  3 ++
 4 files changed, 167 insertions(+)

diff --git a/app/test/test_mempool.c b/app/test/test_mempool.c
index ad7ebd6363..3f7ba5872d 100644
--- a/app/test/test_mempool.c
+++ b/app/test/test_mempool.c
@@ -843,16 +843,19 @@ test_mempool(void)
 	int ret = -1;
 	uint32_t nb_objs = 0;
 	uint32_t nb_mem_chunks = 0;
+	size_t alignment = 0;
 	struct rte_mempool *mp_cache = NULL;
 	struct rte_mempool *mp_nocache = NULL;
 	struct rte_mempool *mp_stack_anon = NULL;
 	struct rte_mempool *mp_stack_mempool_iter = NULL;
 	struct rte_mempool *mp_stack = NULL;
 	struct rte_mempool *default_pool = NULL;
+	struct rte_mempool *mp_alignment = NULL;
 	struct mp_data cb_arg = {
 		.ret = -1
 	};
 	const char *default_pool_ops = rte_mbuf_best_mempool_ops();
+	struct rte_mempool_mem_range_info mem_range = { 0 };

 	/* create a mempool (without cache) */
 	mp_nocache = rte_mempool_create("test_nocache", MEMPOOL_SIZE,
@@ -967,6 +970,72 @@ test_mempool(void)
 	}
 	rte_mempool_obj_iter(default_pool, my_obj_init, NULL);

+	if (rte_mempool_get_mem_range(default_pool, &mem_range)) {
+		printf("cannot get mem range from default mempool\n");
+		GOTO_ERR(ret, err);
+	}
+
+	if (rte_mempool_get_mem_range(NULL, NULL) != -EINVAL) {
+		printf("rte_mempool_get_mem_range failed to return -EINVAL "
+				"when passed invalid arguments\n");
+		GOTO_ERR(ret, err);
+	}
+
+	if (mem_range.start == NULL || mem_range.length <
+			(MEMPOOL_SIZE * MEMPOOL_ELT_SIZE)) {
+		printf("mem range of default mempool is invalid\n");
+		GOTO_ERR(ret, err);
+	}
+
+	/* by default mempool objects are aligned by RTE_MEMPOOL_ALIGN */
+	alignment = rte_mempool_get_obj_alignment(default_pool);
+	if (alignment != RTE_MEMPOOL_ALIGN) {
+		printf("rte_mempool_get_obj_alignment returned wrong value, "
+				"expected %zu, returned %zu\n",
+				(size_t)RTE_MEMPOOL_ALIGN, alignment);
+		GOTO_ERR(ret, err);
+	}
+
+	/* create a mempool with a RTE_MEMPOOL_F_NO_CACHE_ALIGN flag */
+	mp_alignment = rte_mempool_create("test_alignment",
+		1, 8, /* the small size guarantees single memory chunk */
+		0, 0, NULL, NULL, my_obj_init, NULL,
+		SOCKET_ID_ANY, RTE_MEMPOOL_F_NO_CACHE_ALIGN);
+
+	if (mp_alignment == NULL) {
+		printf("cannot allocate mempool with "
+				"RTE_MEMPOOL_F_NO_CACHE_ALIGN flag\n");
+		GOTO_ERR(ret, err);
+	}
+
+	/* mempool was created with RTE_MEMPOOL_F_NO_CACHE_ALIGN
+	 * and minimum alignment is expected which is sizeof(uint64_t)
+	 */
+	alignment = rte_mempool_get_obj_alignment(mp_alignment);
+	if (alignment != sizeof(uint64_t)) {
+		printf("rte_mempool_get_obj_alignment returned wrong value, "
+				"expected %zu, returned %zu\n",
+				(size_t)sizeof(uint64_t), alignment);
+		GOTO_ERR(ret, err);
+	}
+
+	alignment = rte_mempool_get_obj_alignment(NULL);
+	if (alignment != 0) {
+		printf("rte_mempool_get_obj_alignment failed to return 0 for "
+				" an invalid mempool\n");
+		GOTO_ERR(ret, err);
+	}
+
+	if (rte_mempool_get_mem_range(mp_alignment, &mem_range)) {
+		printf("cannot get mem range from mempool\n");
+		GOTO_ERR(ret, err);
+	}
+
+	if (!mem_range.is_contiguous) {
+		printf("mempool not contiguous\n");
+		GOTO_ERR(ret, err);
+	}
+
 	/* retrieve the mempool from its name */
 	if (rte_mempool_lookup("test_nocache") != mp_nocache) {
 		printf("Cannot lookup mempool from its name\n");
@@ -1039,6 +1108,7 @@ test_mempool(void)
 	rte_mempool_free(mp_stack_mempool_iter);
 	rte_mempool_free(mp_stack);
 	rte_mempool_free(default_pool);
+	rte_mempool_free(mp_alignment);

 	return ret;
 }
diff --git a/lib/mempool/rte_mempool.c b/lib/mempool/rte_mempool.c
index 12390a2c81..71100bff4f 100644
--- a/lib/mempool/rte_mempool.c
+++ b/lib/mempool/rte_mempool.c
@@ -1386,6 +1386,51 @@ void rte_mempool_walk(void (*func)(struct rte_mempool *, void *),
 	rte_mcfg_mempool_read_unlock();
 }

+int rte_mempool_get_mem_range(const struct rte_mempool *mp,
+		struct rte_mempool_mem_range_info *mem_range)
+{
+	void *address_low = (void *)UINTPTR_MAX;
+	void *address_high = 0;
+	size_t address_diff = 0;
+	size_t total_size = 0;
+	struct rte_mempool_memhdr *hdr;
+
+	if (mp == NULL || mem_range == NULL)
+		return -EINVAL;
+
+	/* go through memory chunks and find the lowest and highest addresses */
+	STAILQ_FOREACH(hdr, &mp->mem_list, next) {
+		if (address_low > hdr->addr)
+			address_low = hdr->addr;
+		if (address_high < RTE_PTR_ADD(hdr->addr, hdr->len))
+			address_high = RTE_PTR_ADD(hdr->addr, hdr->len);
+		total_size += hdr->len;
+	}
+
+	/* check if mempool was not populated yet (no memory chunks) */
+	if (address_low == (void *)UINTPTR_MAX)
+		return -EINVAL;
+
+	address_diff = (size_t)RTE_PTR_DIFF(address_high, address_low);
+
+	mem_range->start = address_low;
+	mem_range->length = address_diff;
+	mem_range->is_contiguous = (total_size == address_diff) ? true : false;
+
+	return 0;
+}
+
+size_t rte_mempool_get_obj_alignment(const struct rte_mempool *mp)
+{
+	if (mp == NULL)
+		return 0;
+
+	if (mp->flags & RTE_MEMPOOL_F_NO_CACHE_ALIGN)
+		return sizeof(uint64_t);
+	else
+		return RTE_MEMPOOL_ALIGN;
+}
+
 struct mempool_callback_data {
 	TAILQ_ENTRY(mempool_callback_data) callbacks;
 	rte_mempool_event_callback *func;
diff --git a/lib/mempool/rte_mempool.h b/lib/mempool/rte_mempool.h
index 23fd5c8465..e11282763d 100644
--- a/lib/mempool/rte_mempool.h
+++ b/lib/mempool/rte_mempool.h
@@ -1917,6 +1917,55 @@ uint32_t rte_mempool_calc_obj_size(uint32_t elt_size, uint32_t flags,
 void rte_mempool_walk(void (*func)(struct rte_mempool *, void *arg),
 		      void *arg);

+/**
+ * A structure used to retrieve information about the memory range
+ * of the mempool.
+ */
+struct rte_mempool_mem_range_info {
+	/** Start of the memory range used by mempool objects */
+	void *start;
+	/** Length of the memory range used by mempool objects */
+	size_t length;
+	/** Are all memory addresses used by mempool objects contiguous */
+	bool is_contiguous;
+};
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * Get information about the memory range used by the mempool.
+ *
+ * @param[in] mp
+ *   Pointer to an initialized mempool.
+ * @param[out] mem_range
+ *   Pointer to struct which is used to return lowest address,
+ *   length of the memory range containing all the addresses,
+ *   and whether these addresses are contiguous.
+ * @return
+ *   0 on success, -EINVAL if mempool is not valid or mem_range is NULL.
+ **/
+__rte_experimental
+int
+rte_mempool_get_mem_range(const struct rte_mempool *mp,
+		struct rte_mempool_mem_range_info *mem_range);
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * Return object alignment.
+ *
+ * @param[in] mp
+ *   Pointer to a mempool.
+ * @return
+ *   Object alignment if mp is valid. 0 if mp is NULL.
+ *
+ **/
+__rte_experimental
+size_t
+rte_mempool_get_obj_alignment(const struct rte_mempool *mp);
+
 /**
  * @internal Get page size used for mempool object allocation.
  * This function is internal to mempool library and mempool drivers.
diff --git a/lib/mempool/version.map b/lib/mempool/version.map
index 473277400c..02df634b2a 100644
--- a/lib/mempool/version.map
+++ b/lib/mempool/version.map
@@ -50,6 +50,9 @@ EXPERIMENTAL {
 	__rte_mempool_trace_get_contig_blocks;
 	__rte_mempool_trace_default_cache;
 	__rte_mempool_trace_cache_flush;
+	# added in 24.07
+	rte_mempool_get_mem_range;
+	rte_mempool_get_obj_alignment;
 };

 INTERNAL {
--
2.25.1