[dpdk-dev] [PATCH v9 3/5] kni: add app specific mempool create & free routine

[<vattunuru@marvell.com>]

From: Vamsi Attunuru <vattunuru@marvell.com>

When KNI operates in IOVA = VA mode, it requires mbuf memory
to be physically contiguous to ensure KNI kernel module could
translate IOVA addresses properly. Patch adds a KNI specific
mempool create routine to populate the KNI packet mbuf pool
with memory objects that are being on a page.

KNI applications need to use this mempool create & free routines
so that mbuf related requirements in IOVA = VA mode are handled
inside those routines based on the enabled mode.

Updated the release notes with these new routine details.

Signed-off-by: Vamsi Attunuru <vattunuru@marvell.com>
---
 doc/guides/rel_notes/release_19_08.rst |  6 ++++
 examples/kni/main.c                    |  5 ++-
 lib/librte_kni/Makefile                |  1 +
 lib/librte_kni/meson.build             |  1 +
 lib/librte_kni/rte_kni.c               | 60 ++++++++++++++++++++++++++++++++++
 lib/librte_kni/rte_kni.h               | 48 +++++++++++++++++++++++++++
 lib/librte_kni/rte_kni_version.map     |  2 ++
 7 files changed, 122 insertions(+), 1 deletion(-)

diff --git a/doc/guides/rel_notes/release_19_08.rst b/doc/guides/rel_notes/release_19_08.rst
index c9bd3ce..b200aae 100644
--- a/doc/guides/rel_notes/release_19_08.rst
+++ b/doc/guides/rel_notes/release_19_08.rst
@@ -301,6 +301,12 @@ API Changes
   best-effort tc, and qsize field of struct ``rte_sched_port_params`` is
   changed to allow different size of the each queue.
 
+* kni: ``rte_kni_pktmbuf_pool_create`` ``rte_kni_pktmbuf_pool_free`` functions
+  were introduced for KNI applications for creating & freeing packet pool.
+  Since IOVA=VA mode was added in KNI, packet pool's mbuf memory should be
+  physically contiguous for the KNI kernel module to work in IOVA=VA mode,
+  this requirement was taken care in the kni packet pool creation fucntions.
+
 
 ABI Changes
 -----------
diff --git a/examples/kni/main.c b/examples/kni/main.c
index 4710d71..fdfeed2 100644
--- a/examples/kni/main.c
+++ b/examples/kni/main.c
@@ -975,7 +975,7 @@ main(int argc, char** argv)
 		rte_exit(EXIT_FAILURE, "Could not parse input parameters\n");
 
 	/* Create the mbuf pool */
-	pktmbuf_pool = rte_pktmbuf_pool_create("mbuf_pool", NB_MBUF,
+	pktmbuf_pool = rte_kni_pktmbuf_pool_create("mbuf_pool", NB_MBUF,
 		MEMPOOL_CACHE_SZ, 0, MBUF_DATA_SZ, rte_socket_id());
 	if (pktmbuf_pool == NULL) {
 		rte_exit(EXIT_FAILURE, "Could not initialise mbuf pool\n");
@@ -1043,6 +1043,9 @@ main(int argc, char** argv)
 			continue;
 		kni_free_kni(port);
 	}
+
+	rte_kni_pktmbuf_pool_free(pktmbuf_pool);
+
 	for (i = 0; i < RTE_MAX_ETHPORTS; i++)
 		if (kni_port_params_array[i]) {
 			rte_free(kni_port_params_array[i]);
diff --git a/lib/librte_kni/Makefile b/lib/librte_kni/Makefile
index ab15d10..5e3dd01 100644
--- a/lib/librte_kni/Makefile
+++ b/lib/librte_kni/Makefile
@@ -6,6 +6,7 @@ include $(RTE_SDK)/mk/rte.vars.mk
 # library name
 LIB = librte_kni.a
 
+CFLAGS += -DALLOW_EXPERIMENTAL_API
 CFLAGS += $(WERROR_FLAGS) -I$(SRCDIR) -O3 -fno-strict-aliasing
 CFLAGS += -I$(RTE_SDK)/drivers/bus/pci
 LDLIBS += -lrte_eal -lrte_mempool -lrte_mbuf -lrte_ethdev
diff --git a/lib/librte_kni/meson.build b/lib/librte_kni/meson.build
index fd46f87..e357445 100644
--- a/lib/librte_kni/meson.build
+++ b/lib/librte_kni/meson.build
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: BSD-3-Clause
 # Copyright(c) 2017 Intel Corporation
 
+allow_experimental_apis = true
 if not is_linux or not dpdk_conf.get('RTE_ARCH_64')
 	build = false
 	reason = 'only supported on 64-bit linux'
diff --git a/lib/librte_kni/rte_kni.c b/lib/librte_kni/rte_kni.c
index 2aaaeaa..15dda45 100644
--- a/lib/librte_kni/rte_kni.c
+++ b/lib/librte_kni/rte_kni.c
@@ -22,6 +22,7 @@
 #include <rte_tailq.h>
 #include <rte_rwlock.h>
 #include <rte_eal_memconfig.h>
+#include <rte_mbuf_pool_ops.h>
 #include <rte_kni_common.h>
 #include "rte_kni_fifo.h"
 
@@ -681,6 +682,65 @@ kni_allocate_mbufs(struct rte_kni *kni)
 	}
 }
 
+struct rte_mempool *
+rte_kni_pktmbuf_pool_create(const char *name, unsigned int n,
+	unsigned int cache_size, uint16_t priv_size, uint16_t data_room_size,
+	int socket_id)
+{
+	struct rte_pktmbuf_pool_private mbp_priv;
+	const char *mp_ops_name;
+	struct rte_mempool *mp;
+	unsigned int elt_size;
+	int ret;
+
+	if (RTE_ALIGN(priv_size, RTE_MBUF_PRIV_ALIGN) != priv_size) {
+		RTE_LOG(ERR, MBUF, "mbuf priv_size=%u is not aligned\n",
+			priv_size);
+		rte_errno = EINVAL;
+		return NULL;
+	}
+	elt_size = sizeof(struct rte_mbuf) + (unsigned int)priv_size +
+		(unsigned int)data_room_size;
+	mbp_priv.mbuf_data_room_size = data_room_size;
+	mbp_priv.mbuf_priv_size = priv_size;
+
+	mp = rte_mempool_create_empty(name, n, elt_size, cache_size,
+		 sizeof(struct rte_pktmbuf_pool_private), socket_id, 0);
+	if (mp == NULL)
+		return NULL;
+
+	mp_ops_name = rte_mbuf_best_mempool_ops();
+	ret = rte_mempool_set_ops_byname(mp, mp_ops_name, NULL);
+	if (ret != 0) {
+		RTE_LOG(ERR, MBUF, "error setting mempool handler\n");
+		rte_mempool_free(mp);
+		rte_errno = -ret;
+		return NULL;
+	}
+	rte_pktmbuf_pool_init(mp, &mbp_priv);
+
+	if (rte_eal_iova_mode() == RTE_IOVA_VA)
+		ret = rte_mempool_populate_from_pg_sz_chunks(mp);
+	else
+		ret = rte_mempool_populate_default(mp);
+
+	if (ret < 0) {
+		rte_mempool_free(mp);
+		rte_errno = -ret;
+		return NULL;
+	}
+
+	rte_mempool_obj_iter(mp, rte_pktmbuf_init, NULL);
+
+	return mp;
+}
+
+void
+rte_kni_pktmbuf_pool_free(struct rte_mempool *mp)
+{
+	rte_mempool_free(mp);
+}
+
 struct rte_kni *
 rte_kni_get(const char *name)
 {
diff --git a/lib/librte_kni/rte_kni.h b/lib/librte_kni/rte_kni.h
index 5699a64..99d263d 100644
--- a/lib/librte_kni/rte_kni.h
+++ b/lib/librte_kni/rte_kni.h
@@ -184,6 +184,54 @@ unsigned rte_kni_tx_burst(struct rte_kni *kni, struct rte_mbuf **mbufs,
 		unsigned num);
 
 /**
+ * Create a kni packet mbuf pool.
+ *
+ * This function creates and initializes a packet mbuf pool for KNI applications
+ * It calls the required mempool populate routine based on the IOVA mode.
+ *
+ * @param name
+ *   The name of the mbuf pool.
+ * @param n
+ *   The number of elements in the mbuf pool. The optimum size (in terms
+ *   of memory usage) for a mempool is when n is a power of two minus one:
+ *   n = (2^q - 1).
+ * @param cache_size
+ *   Size of the per-core object cache. See rte_mempool_create() for
+ *   details.
+ * @param priv_size
+ *   Size of application private are between the rte_mbuf structure
+ *   and the data buffer. This value must be aligned to RTE_MBUF_PRIV_ALIGN.
+ * @param data_room_size
+ *   Size of data buffer in each mbuf, including RTE_PKTMBUF_HEADROOM.
+ * @param socket_id
+ *   The socket identifier where the memory should be allocated. The
+ *   value can be *SOCKET_ID_ANY* if there is no NUMA constraint for the
+ *   reserved zone.
+ * @return
+ *   The pointer to the new allocated mempool, on success. NULL on error
+ *   with rte_errno set appropriately. Possible rte_errno values include:
+ *    - E_RTE_NO_CONFIG - function could not get pointer to rte_config structure
+ *    - E_RTE_SECONDARY - function was called from a secondary process instance
+ *    - EINVAL - cache size provided is too large, or priv_size is not aligned.
+ *    - ENOSPC - the maximum number of memzones has already been allocated
+ *    - EEXIST - a memzone with the same name already exists
+ *    - ENOMEM - no appropriate memory area found in which to create memzone
+ */
+__rte_experimental
+struct rte_mempool *rte_kni_pktmbuf_pool_create(const char *name,
+		unsigned int n, unsigned int cache_size, uint16_t priv_size,
+		uint16_t data_room_size, int socket_id);
+
+/**
+ * Free the given packet mempool.
+ *
+ * @param mp
+ *  The mempool pointer.
+ */
+__rte_experimental
+void rte_kni_pktmbuf_pool_free(struct rte_mempool *mp);
+
+/**
  * Get the KNI context of its name.
  *
  * @param name
diff --git a/lib/librte_kni/rte_kni_version.map b/lib/librte_kni/rte_kni_version.map
index c877dc6..aba9728 100644
--- a/lib/librte_kni/rte_kni_version.map
+++ b/lib/librte_kni/rte_kni_version.map
@@ -20,4 +20,6 @@ EXPERIMENTAL {
 	global:
 
 	rte_kni_update_link;
+	rte_kni_pktmbuf_pool_create;
+	rte_kni_pktmbuf_pool_free;
 };
-- 
2.8.4