[dpdk-dev] [PATCH 0/2] ring: allow to init a rte_ring outside of an rte_memzone

[dpdk-dev] [PATCH 0/2] ring: allow to init a rte_ring outside of an rte_memzone

[Olivier Matz]

These 2 patches adds 2 new functions that permits to initialize and use
a rte_ring anywhere in memory.

Before this patches, only rte_ring_create() was available. This function
allocates a rte_memzone (that cannot be freed) and initializes a ring
inside.

This series allows to do the following:
  size = rte_ring_get_memsize(1024);
  r = malloc(size);
  rte_ring_init(r, "my_ring", 1024, 0);


Olivier Matz (2):
  ring: introduce rte_ring_get_memsize()
  ring: introduce rte_ring_init()

 lib/librte_ring/rte_ring.c | 88 +++++++++++++++++++++++++++++-----------------
 lib/librte_ring/rte_ring.h | 67 ++++++++++++++++++++++++++++++++---
 2 files changed, 118 insertions(+), 37 deletions(-)

-- 
1.9.2

[dpdk-dev] [PATCH 1/2] ring: introduce rte_ring_get_memsize()

[Olivier Matz]

Add a function that returns the amount of memory occupied by a rte_ring
structure and its object table. This commit prepares the next one that
will allow to allocate a ring dynamically.

Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
---
 lib/librte_ring/rte_ring.c | 29 ++++++++++++++++++++++-------
 lib/librte_ring/rte_ring.h | 16 ++++++++++++++++
 2 files changed, 38 insertions(+), 7 deletions(-)

diff --git a/lib/librte_ring/rte_ring.c b/lib/librte_ring/rte_ring.c
index 0d43a55..4aa500f 100644
--- a/lib/librte_ring/rte_ring.c
+++ b/lib/librte_ring/rte_ring.c
@@ -94,6 +94,24 @@ TAILQ_HEAD(rte_ring_list, rte_ring);
 /* true if x is a power of 2 */
 #define POWEROF2(x) ((((x)-1) & (x)) == 0)
 
+/* return the size of memory occupied by a ring */
+ssize_t rte_ring_get_memsize(unsigned count)
+{
+	ssize_t sz;
+
+	/* count must be a power of 2 */
+	if ((!POWEROF2(count)) || (count > RTE_RING_SZ_MASK )) {
+		RTE_LOG(ERR, RING,
+			"Requested size is invalid, must be power of 2, and "
+			"do not exceed the size limit %u\n", RTE_RING_SZ_MASK);
+		return -EINVAL;
+	}
+
+	sz = sizeof(struct rte_ring) + count * sizeof(void *);
+	sz = (sz + CACHE_LINE_MASK) & (~CACHE_LINE_MASK);
+	return sz;
+}
+
 /* create the ring */
 struct rte_ring *
 rte_ring_create(const char *name, unsigned count, int socket_id,
@@ -102,7 +120,7 @@ rte_ring_create(const char *name, unsigned count, int socket_id,
 	char mz_name[RTE_MEMZONE_NAMESIZE];
 	struct rte_ring *r;
 	const struct rte_memzone *mz;
-	size_t ring_size;
+	ssize_t ring_size;
 	int mz_flags = 0;
 	struct rte_ring_list* ring_list = NULL;
 
@@ -129,16 +147,13 @@ rte_ring_create(const char *name, unsigned count, int socket_id,
 		return NULL;	
 	}
 
-	/* count must be a power of 2 */
-	if ((!POWEROF2(count)) || (count > RTE_RING_SZ_MASK )) {
-		rte_errno = EINVAL;
-		RTE_LOG(ERR, RING, "Requested size is invalid, must be power of 2, and "
-				"do not exceed the size limit %u\n", RTE_RING_SZ_MASK);
+	ring_size = rte_ring_get_memsize(count);
+	if (ring_size < 0) {
+		rte_errno = ring_size;
 		return NULL;
 	}
 
 	rte_snprintf(mz_name, sizeof(mz_name), "%s%s", RTE_RING_MZ_PREFIX, name);
-	ring_size = count * sizeof(void *) + sizeof(struct rte_ring);
 
 	rte_rwlock_write_lock(RTE_EAL_TAILQ_RWLOCK);
 
diff --git a/lib/librte_ring/rte_ring.h b/lib/librte_ring/rte_ring.h
index 775ea79..e8493f2 100644
--- a/lib/librte_ring/rte_ring.h
+++ b/lib/librte_ring/rte_ring.h
@@ -199,6 +199,22 @@ struct rte_ring {
 #endif
 
 /**
+ * Calculate the memory size needed for a ring
+ *
+ * This function returns the number of bytes needed for a ring, given
+ * the number of elements in it. This value is the sum of the size of
+ * the structure rte_ring and the size of the memory needed by the
+ * objects pointers. The value is aligned to a cache line size.
+ *
+ * @param count
+ *   The number of elements in the ring (must be a power of 2).
+ * @return
+ *   - The memory size needed for the ring on success.
+ *   - -EINVAL if count is not a power of 2.
+ */
+ssize_t rte_ring_get_memsize(unsigned count);
+
+/**
  * Create a new ring named *name* in memory.
  *
  * This function uses ``memzone_reserve()`` to allocate memory. Its size is
-- 
1.9.2

[dpdk-dev] [PATCH 2/2] ring: introduce rte_ring_init()

[Olivier Matz]

Allow to initialize a ring in an already allocated memory. The rte_ring_create()
function that allocates a ring in a rte_memzone is still available and now uses
the new rte_ring_init() function in order to factorize the code.

Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
---
 lib/librte_ring/rte_ring.c | 63 ++++++++++++++++++++++++++--------------------
 lib/librte_ring/rte_ring.h | 51 +++++++++++++++++++++++++++++++++----
 2 files changed, 82 insertions(+), 32 deletions(-)

diff --git a/lib/librte_ring/rte_ring.c b/lib/librte_ring/rte_ring.c
index 4aa500f..a65f33e 100644
--- a/lib/librte_ring/rte_ring.c
+++ b/lib/librte_ring/rte_ring.c
@@ -112,18 +112,10 @@ ssize_t rte_ring_get_memsize(unsigned count)
 	return sz;
 }
 
-/* create the ring */
-struct rte_ring *
-rte_ring_create(const char *name, unsigned count, int socket_id,
-		unsigned flags)
+int
+rte_ring_init(struct rte_ring *r, const char *name, unsigned count,
+	unsigned flags)
 {
-	char mz_name[RTE_MEMZONE_NAMESIZE];
-	struct rte_ring *r;
-	const struct rte_memzone *mz;
-	ssize_t ring_size;
-	int mz_flags = 0;
-	struct rte_ring_list* ring_list = NULL;
-
 	/* compilation-time checks */
 	RTE_BUILD_BUG_ON((sizeof(struct rte_ring) &
 			  CACHE_LINE_MASK) != 0);
@@ -140,11 +132,38 @@ rte_ring_create(const char *name, unsigned count, int socket_id,
 			  CACHE_LINE_MASK) != 0);
 #endif
 
+	/* init the ring structure */
+	memset(r, 0, sizeof(*r));
+	rte_snprintf(r->name, sizeof(r->name), "%s", name);
+	r->flags = flags;
+	r->prod.watermark = count;
+	r->prod.sp_enqueue = !!(flags & RING_F_SP_ENQ);
+	r->cons.sc_dequeue = !!(flags & RING_F_SC_DEQ);
+	r->prod.size = r->cons.size = count;
+	r->prod.mask = r->cons.mask = count-1;
+	r->prod.head = r->cons.head = 0;
+	r->prod.tail = r->cons.tail = 0;
+
+	return 0;
+}
+
+/* create the ring */
+struct rte_ring *
+rte_ring_create(const char *name, unsigned count, int socket_id,
+		unsigned flags)
+{
+	char mz_name[RTE_MEMZONE_NAMESIZE];
+	struct rte_ring *r;
+	const struct rte_memzone *mz;
+	ssize_t ring_size;
+	int mz_flags = 0;
+	struct rte_ring_list* ring_list = NULL;
+
 	/* check that we have an initialised tail queue */
-	if ((ring_list = 
+	if ((ring_list =
 	     RTE_TAILQ_LOOKUP_BY_IDX(RTE_TAILQ_RING, rte_ring_list)) == NULL) {
 		rte_errno = E_RTE_NO_TAILQ;
-		return NULL;	
+		return NULL;
 	}
 
 	ring_size = rte_ring_get_memsize(count);
@@ -163,26 +182,16 @@ rte_ring_create(const char *name, unsigned count, int socket_id,
 	mz = rte_memzone_reserve(mz_name, ring_size, socket_id, mz_flags);
 	if (mz != NULL) {
 		r = mz->addr;
-
-		/* init the ring structure */
-		memset(r, 0, sizeof(*r));
-		rte_snprintf(r->name, sizeof(r->name), "%s", name);
-		r->flags = flags;
-		r->prod.watermark = count;
-		r->prod.sp_enqueue = !!(flags & RING_F_SP_ENQ);
-		r->cons.sc_dequeue = !!(flags & RING_F_SC_DEQ);
-		r->prod.size = r->cons.size = count;
-		r->prod.mask = r->cons.mask = count-1;
-		r->prod.head = r->cons.head = 0;
-		r->prod.tail = r->cons.tail = 0;
-
+		/* no need to check return value here, we already checked the
+		 * arguments above */
+		rte_ring_init(r, name, count, flags);
 		TAILQ_INSERT_TAIL(ring_list, r, next);
 	} else {
 		r = NULL;
 		RTE_LOG(ERR, RING, "Cannot reserve memory\n");
 	}
 	rte_rwlock_write_unlock(RTE_EAL_TAILQ_RWLOCK);
-	
+
 	return r;
 }
 
diff --git a/lib/librte_ring/rte_ring.h b/lib/librte_ring/rte_ring.h
index e8493f2..c62e7d7 100644
--- a/lib/librte_ring/rte_ring.h
+++ b/lib/librte_ring/rte_ring.h
@@ -215,13 +215,54 @@ struct rte_ring {
 ssize_t rte_ring_get_memsize(unsigned count);
 
 /**
+ * Initialize a ring structure.
+ *
+ * Initialize a ring structure in memory pointed by "r". The size of the
+ * memory area must be large enough to store the ring structure and the
+ * object table. It is advised to use rte_ring_get_memsize() to get the
+ * appropriate size.
+ *
+ * The ring size is set to *count*, which must be a power of two. Water
+ * marking is disabled by default. The real usable ring size is
+ * *count-1* instead of *count* to differentiate a free ring from an
+ * empty ring.
+ *
+ * The ring is not added in RTE_TAILQ_RING global list. Indeed, the
+ * memory given by the caller may not be shareable among dpdk
+ * processes.
+ *
+ * @param r
+ *   The pointer to the ring structure followed by the objects table.
+ * @param name
+ *   The size of the ring.
+ * @param count
+ *   The number of elements in the ring (must be a power of 2).
+ * @param flags
+ *   An OR of the following:
+ *    - RING_F_SP_ENQ: If this flag is set, the default behavior when
+ *      using ``rte_ring_enqueue()`` or ``rte_ring_enqueue_bulk()``
+ *      is "single-producer". Otherwise, it is "multi-producers".
+ *    - RING_F_SC_DEQ: If this flag is set, the default behavior when
+ *      using ``rte_ring_dequeue()`` or ``rte_ring_dequeue_bulk()``
+ *      is "single-consumer". Otherwise, it is "multi-consumers".
+ * @return
+ *   0 on success, or a negative value on error.
+ */
+int rte_ring_init(struct rte_ring *r, const char *name, unsigned count,
+	unsigned flags);
+
+/**
  * Create a new ring named *name* in memory.
  *
- * This function uses ``memzone_reserve()`` to allocate memory. Its size is
- * set to *count*, which must be a power of two. Water marking is
- * disabled by default.
- * Note that the real usable ring size is *count-1* instead of
- * *count*.
+ * This function uses ``memzone_reserve()`` to allocate memory. Then it
+ * calls rte_ring_init() to initialize an empty ring.
+ *
+ * The new ring size is set to *count*, which must be a power of
+ * two. Water marking is disabled by default. The real usable ring size
+ * is *count-1* instead of *count* to differentiate a free ring from an
+ * empty ring.
+ *
+ * The ring is added in RTE_TAILQ_RING list.
  *
  * @param name
  *   The name of the ring.
-- 
1.9.2

Re: [dpdk-dev] [PATCH 1/2] ring: introduce rte_ring_get_memsize()

[Ananyev, Konstantin]

Hi Oliver,

2 nits from me:

1. ssize_t rte_ring_get_memsize(unsigned count)

Can you use usual syntax for functions definitions in DPDK:

ssize_t
rte_ring_get_memsize(unsigned count)

2. sz = (sz + CACHE_LINE_MASK) & (~CACHE_LINE_MASK);

Use RTE_ALIGN(sz, CACHE_LINE_SIZE) instead?

Konstantin

-----Original Message-----
From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Olivier Matz
Sent: Wednesday, May 07, 2014 12:39 PM
To: dev@dpdk.org
Subject: [dpdk-dev] [PATCH 1/2] ring: introduce rte_ring_get_memsize()

Add a function that returns the amount of memory occupied by a rte_ring
structure and its object table. This commit prepares the next one that
will allow to allocate a ring dynamically.

Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
---
 lib/librte_ring/rte_ring.c | 29 ++++++++++++++++++++++-------
 lib/librte_ring/rte_ring.h | 16 ++++++++++++++++
 2 files changed, 38 insertions(+), 7 deletions(-)

diff --git a/lib/librte_ring/rte_ring.c b/lib/librte_ring/rte_ring.c
index 0d43a55..4aa500f 100644
--- a/lib/librte_ring/rte_ring.c
+++ b/lib/librte_ring/rte_ring.c
@@ -94,6 +94,24 @@ TAILQ_HEAD(rte_ring_list, rte_ring);
 /* true if x is a power of 2 */
 #define POWEROF2(x) ((((x)-1) & (x)) == 0)
 
+/* return the size of memory occupied by a ring */
+ssize_t rte_ring_get_memsize(unsigned count)
+{
+	ssize_t sz;
+
+	/* count must be a power of 2 */
+	if ((!POWEROF2(count)) || (count > RTE_RING_SZ_MASK )) {
+		RTE_LOG(ERR, RING,
+			"Requested size is invalid, must be power of 2, and "
+			"do not exceed the size limit %u\n", RTE_RING_SZ_MASK);
+		return -EINVAL;
+	}
+
+	sz = sizeof(struct rte_ring) + count * sizeof(void *);
+	sz = (sz + CACHE_LINE_MASK) & (~CACHE_LINE_MASK);
+	return sz;
+}
+
 /* create the ring */
 struct rte_ring *
 rte_ring_create(const char *name, unsigned count, int socket_id,
@@ -102,7 +120,7 @@ rte_ring_create(const char *name, unsigned count, int socket_id,
 	char mz_name[RTE_MEMZONE_NAMESIZE];
 	struct rte_ring *r;
 	const struct rte_memzone *mz;
-	size_t ring_size;
+	ssize_t ring_size;
 	int mz_flags = 0;
 	struct rte_ring_list* ring_list = NULL;
 
@@ -129,16 +147,13 @@ rte_ring_create(const char *name, unsigned count, int socket_id,
 		return NULL;	
 	}
 
-	/* count must be a power of 2 */
-	if ((!POWEROF2(count)) || (count > RTE_RING_SZ_MASK )) {
-		rte_errno = EINVAL;
-		RTE_LOG(ERR, RING, "Requested size is invalid, must be power of 2, and "
-				"do not exceed the size limit %u\n", RTE_RING_SZ_MASK);
+	ring_size = rte_ring_get_memsize(count);
+	if (ring_size < 0) {
+		rte_errno = ring_size;
 		return NULL;
 	}
 
 	rte_snprintf(mz_name, sizeof(mz_name), "%s%s", RTE_RING_MZ_PREFIX, name);
-	ring_size = count * sizeof(void *) + sizeof(struct rte_ring);
 
 	rte_rwlock_write_lock(RTE_EAL_TAILQ_RWLOCK);
 
diff --git a/lib/librte_ring/rte_ring.h b/lib/librte_ring/rte_ring.h
index 775ea79..e8493f2 100644
--- a/lib/librte_ring/rte_ring.h
+++ b/lib/librte_ring/rte_ring.h
@@ -199,6 +199,22 @@ struct rte_ring {
 #endif
 
 /**
+ * Calculate the memory size needed for a ring
+ *
+ * This function returns the number of bytes needed for a ring, given
+ * the number of elements in it. This value is the sum of the size of
+ * the structure rte_ring and the size of the memory needed by the
+ * objects pointers. The value is aligned to a cache line size.
+ *
+ * @param count
+ *   The number of elements in the ring (must be a power of 2).
+ * @return
+ *   - The memory size needed for the ring on success.
+ *   - -EINVAL if count is not a power of 2.
+ */
+ssize_t rte_ring_get_memsize(unsigned count);
+
+/**
  * Create a new ring named *name* in memory.
  *
  * This function uses ``memzone_reserve()`` to allocate memory. Its size is
-- 
1.9.2

Re: [dpdk-dev] [PATCH 1/2] ring: introduce rte_ring_get_memsize()

[Olivier MATZ]

Hi Konstantin,

On 05/07/2014 02:35 PM, Ananyev, Konstantin wrote:
> 1. ssize_t rte_ring_get_memsize(unsigned count)
>
> Can you use usual syntax for functions definitions in DPDK:
>
> ssize_t
> rte_ring_get_memsize(unsigned count)
>
> 2. sz = (sz + CACHE_LINE_MASK) & (~CACHE_LINE_MASK);
>
> Use RTE_ALIGN(sz, CACHE_LINE_SIZE) instead?

Thank you for reviewing. I'll include these 2 changes in
a patch-v2.

Regards,
Olivier