ring: return free space when enqueuing

[dpdk.git] / lib / librte_ring / rte_ring.h

diff --git a/lib/librte_ring/rte_ring.h b/lib/librte_ring/rte_ring.h
index 34b438c..439698b 100644 (file)
--- a/lib/librte_ring/rte_ring.h
+++ b/lib/librte_ring/rte_ring.h
@@ -354,20 +354,16 @@ void rte_ring_dump(FILE *f, const struct rte_ring *r);
  */
 static inline unsigned int __attribute__((always_inline))
 __rte_ring_mp_do_enqueue(struct rte_ring *r, void * const *obj_table,
-                        unsigned n, enum rte_ring_queue_behavior behavior)
+                        unsigned int n, enum rte_ring_queue_behavior behavior,
+                        unsigned int *free_space)
 {
        uint32_t prod_head, prod_next;
        uint32_t cons_tail, free_entries;
-       const unsigned max = n;
+       const unsigned int max = n;
        int success;
        unsigned int i;
        uint32_t mask = r->mask;
 
-       /* Avoid the unnecessary cmpset operation below, which is also
-        * potentially harmful when n equals 0. */
-       if (n == 0)
-               return 0;
-
        /* move prod.head atomically */
        do {
                /* Reset n to the initial burst count */
@@ -382,16 +378,12 @@ __rte_ring_mp_do_enqueue(struct rte_ring *r, void * const *obj_table,
                free_entries = (mask + cons_tail - prod_head);
 
                /* check that we have enough room in ring */
-               if (unlikely(n > free_entries)) {
-                       if (behavior == RTE_RING_QUEUE_FIXED)
-                               return 0;
-                       else {
-                               /* No free entry available */
-                               if (unlikely(free_entries == 0))
-                                       return 0;
-                               n = free_entries;
-                       }
-               }
+               if (unlikely(n > free_entries))
+                       n = (behavior == RTE_RING_QUEUE_FIXED) ?
+                                       0 : free_entries;
+
+               if (n == 0)
+                       goto end;
 
                prod_next = prod_head + n;
                success = rte_atomic32_cmpset(&r->prod.head, prod_head,
@@ -410,6 +402,9 @@ __rte_ring_mp_do_enqueue(struct rte_ring *r, void * const *obj_table,
                rte_pause();
 
        r->prod.tail = prod_next;
+end:
+       if (free_space != NULL)
+               *free_space = free_entries - n;
        return n;
 }
 
@@ -431,7 +426,8 @@ __rte_ring_mp_do_enqueue(struct rte_ring *r, void * const *obj_table,
  */
 static inline unsigned int __attribute__((always_inline))
 __rte_ring_sp_do_enqueue(struct rte_ring *r, void * const *obj_table,
-                        unsigned n, enum rte_ring_queue_behavior behavior)
+                        unsigned int n, enum rte_ring_queue_behavior behavior,
+                        unsigned int *free_space)
 {
        uint32_t prod_head, cons_tail;
        uint32_t prod_next, free_entries;
@@ -447,16 +443,12 @@ __rte_ring_sp_do_enqueue(struct rte_ring *r, void * const *obj_table,
        free_entries = mask + cons_tail - prod_head;
 
        /* check that we have enough room in ring */
-       if (unlikely(n > free_entries)) {
-               if (behavior == RTE_RING_QUEUE_FIXED)
-                       return 0;
-               else {
-                       /* No free entry available */
-                       if (unlikely(free_entries == 0))
-                               return 0;
-                       n = free_entries;
-               }
-       }
+       if (unlikely(n > free_entries))
+               n = (behavior == RTE_RING_QUEUE_FIXED) ? 0 : free_entries;
+
+       if (n == 0)
+               goto end;
+
 
        prod_next = prod_head + n;
        r->prod.head = prod_next;
@@ -466,6 +458,9 @@ __rte_ring_sp_do_enqueue(struct rte_ring *r, void * const *obj_table,
        rte_smp_wmb();
 
        r->prod.tail = prod_next;
+end:
+       if (free_space != NULL)
+               *free_space = free_entries - n;
        return n;
 }
 
@@ -620,14 +615,18 @@ __rte_ring_sc_do_dequeue(struct rte_ring *r, void **obj_table,
  *   A pointer to a table of void * pointers (objects).
  * @param n
  *   The number of objects to add in the ring from the obj_table.
+ * @param free_space
+ *   if non-NULL, returns the amount of space in the ring after the
+ *   enqueue operation has finished.
  * @return
  *   The number of objects enqueued, either 0 or n
  */
 static inline unsigned int __attribute__((always_inline))
 rte_ring_mp_enqueue_bulk(struct rte_ring *r, void * const *obj_table,
-                        unsigned n)
+                        unsigned int n, unsigned int *free_space)
 {
-       return __rte_ring_mp_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_FIXED);
+       return __rte_ring_mp_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_FIXED,
+                       free_space);
 }
 
 /**
@@ -639,14 +638,18 @@ rte_ring_mp_enqueue_bulk(struct rte_ring *r, void * const *obj_table,
  *   A pointer to a table of void * pointers (objects).
  * @param n
  *   The number of objects to add in the ring from the obj_table.
+ * @param free_space
+ *   if non-NULL, returns the amount of space in the ring after the
+ *   enqueue operation has finished.
  * @return
  *   The number of objects enqueued, either 0 or n
  */
 static inline unsigned int __attribute__((always_inline))
 rte_ring_sp_enqueue_bulk(struct rte_ring *r, void * const *obj_table,
-                        unsigned n)
+                        unsigned int n, unsigned int *free_space)
 {
-       return __rte_ring_sp_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_FIXED);
+       return __rte_ring_sp_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_FIXED,
+                       free_space);
 }
 
 /**
@@ -662,17 +665,20 @@ rte_ring_sp_enqueue_bulk(struct rte_ring *r, void * const *obj_table,
  *   A pointer to a table of void * pointers (objects).
  * @param n
  *   The number of objects to add in the ring from the obj_table.
+ * @param free_space
+ *   if non-NULL, returns the amount of space in the ring after the
+ *   enqueue operation has finished.
  * @return
  *   The number of objects enqueued, either 0 or n
  */
 static inline unsigned int __attribute__((always_inline))
 rte_ring_enqueue_bulk(struct rte_ring *r, void * const *obj_table,
-                     unsigned n)
+                     unsigned int n, unsigned int *free_space)
 {
        if (r->prod.single)
-               return rte_ring_sp_enqueue_bulk(r, obj_table, n);
+               return rte_ring_sp_enqueue_bulk(r, obj_table, n, free_space);
        else
-               return rte_ring_mp_enqueue_bulk(r, obj_table, n);
+               return rte_ring_mp_enqueue_bulk(r, obj_table, n, free_space);
 }
 
 /**
@@ -692,7 +698,7 @@ rte_ring_enqueue_bulk(struct rte_ring *r, void * const *obj_table,
 static inline int __attribute__((always_inline))
 rte_ring_mp_enqueue(struct rte_ring *r, void *obj)
 {
-       return rte_ring_mp_enqueue_bulk(r, &obj, 1) ? 0 : -ENOBUFS;
+       return rte_ring_mp_enqueue_bulk(r, &obj, 1, NULL) ? 0 : -ENOBUFS;
 }
 
 /**
@@ -709,7 +715,7 @@ rte_ring_mp_enqueue(struct rte_ring *r, void *obj)
 static inline int __attribute__((always_inline))
 rte_ring_sp_enqueue(struct rte_ring *r, void *obj)
 {
-       return rte_ring_sp_enqueue_bulk(r, &obj, 1) ? 0 : -ENOBUFS;
+       return rte_ring_sp_enqueue_bulk(r, &obj, 1, NULL) ? 0 : -ENOBUFS;
 }
 
 /**
@@ -730,7 +736,7 @@ rte_ring_sp_enqueue(struct rte_ring *r, void *obj)
 static inline int __attribute__((always_inline))
 rte_ring_enqueue(struct rte_ring *r, void *obj)
 {
-       return rte_ring_enqueue_bulk(r, &obj, 1) ? 0 : -ENOBUFS;
+       return rte_ring_enqueue_bulk(r, &obj, 1, NULL) ? 0 : -ENOBUFS;
 }
 
 /**
@@ -971,14 +977,18 @@ struct rte_ring *rte_ring_lookup(const char *name);
  *   A pointer to a table of void * pointers (objects).
  * @param n
  *   The number of objects to add in the ring from the obj_table.
+ * @param free_space
+ *   if non-NULL, returns the amount of space in the ring after the
+ *   enqueue operation has finished.
  * @return
  *   - n: Actual number of objects enqueued.
  */
 static inline unsigned __attribute__((always_inline))
 rte_ring_mp_enqueue_burst(struct rte_ring *r, void * const *obj_table,
-                        unsigned n)
+                        unsigned int n, unsigned int *free_space)
 {
-       return __rte_ring_mp_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_VARIABLE);
+       return __rte_ring_mp_do_enqueue(r, obj_table, n,
+                       RTE_RING_QUEUE_VARIABLE, free_space);
 }
 
 /**
@@ -990,14 +1000,18 @@ rte_ring_mp_enqueue_burst(struct rte_ring *r, void * const *obj_table,
  *   A pointer to a table of void * pointers (objects).
  * @param n
  *   The number of objects to add in the ring from the obj_table.
+ * @param free_space
+ *   if non-NULL, returns the amount of space in the ring after the
+ *   enqueue operation has finished.
  * @return
  *   - n: Actual number of objects enqueued.
  */
 static inline unsigned __attribute__((always_inline))
 rte_ring_sp_enqueue_burst(struct rte_ring *r, void * const *obj_table,
-                        unsigned n)
+                        unsigned int n, unsigned int *free_space)
 {
-       return __rte_ring_sp_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_VARIABLE);
+       return __rte_ring_sp_do_enqueue(r, obj_table, n,
+                       RTE_RING_QUEUE_VARIABLE, free_space);
 }
 
 /**
@@ -1013,17 +1027,20 @@ rte_ring_sp_enqueue_burst(struct rte_ring *r, void * const *obj_table,
  *   A pointer to a table of void * pointers (objects).
  * @param n
  *   The number of objects to add in the ring from the obj_table.
+ * @param free_space
+ *   if non-NULL, returns the amount of space in the ring after the
+ *   enqueue operation has finished.
  * @return
  *   - n: Actual number of objects enqueued.
  */
 static inline unsigned __attribute__((always_inline))
 rte_ring_enqueue_burst(struct rte_ring *r, void * const *obj_table,
-                     unsigned n)
+                     unsigned int n, unsigned int *free_space)
 {
        if (r->prod.single)
-               return rte_ring_sp_enqueue_burst(r, obj_table, n);
+               return rte_ring_sp_enqueue_burst(r, obj_table, n, free_space);
        else
-               return rte_ring_mp_enqueue_burst(r, obj_table, n);
+               return rte_ring_mp_enqueue_burst(r, obj_table, n, free_space);
 }
 
 /**