remove extra parentheses in return statement

[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 39bacdd..943c97c 100644 (file)
--- a/lib/librte_ring/rte_ring.h
+++ b/lib/librte_ring/rte_ring.h
@@ -101,6 +101,8 @@ extern "C" {
 #include <rte_atomic.h>
 #include <rte_branch_prediction.h>
 
+#define RTE_TAILQ_RING_NAME "RTE_RING"
+
 enum rte_ring_queue_behavior {
        RTE_RING_QUEUE_FIXED = 0, /* Enq/Deq a fixed number of items from a ring */
        RTE_RING_QUEUE_VARIABLE   /* Enq/Deq as many items a possible from ring */
@@ -127,6 +129,13 @@ struct rte_ring_debug_stats {
 #define RTE_RING_NAMESIZE 32 /**< The maximum length of a ring name. */
 #define RTE_RING_MZ_PREFIX "RG_"
 
+#ifndef RTE_RING_PAUSE_REP_COUNT
+#define RTE_RING_PAUSE_REP_COUNT 0 /**< Yield after pause num of times, no yield
+                                    *   if RTE_RING_PAUSE_REP not defined. */
+#endif
+
+struct rte_memzone; /* forward declaration, so as not to require memzone.h */
+
 /**
  * An RTE ring structure.
  *
@@ -140,6 +149,8 @@ struct rte_ring_debug_stats {
 struct rte_ring {
        char name[RTE_RING_NAMESIZE];    /**< Name of the ring. */
        int flags;                       /**< Flags supplied at creation. */
+       const struct rte_memzone *memzone;
+                       /**< Memzone, if any, containing the rte_ring */
 
        /** Ring producer status. */
        struct prod {
@@ -286,7 +297,6 @@ int rte_ring_init(struct rte_ring *r, const char *name, unsigned count,
  *    rte_errno set appropriately. Possible 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
- *    - E_RTE_NO_TAILQ - no tailq list could be got for the ring list
  *    - EINVAL - count provided is not a power of 2
  *    - ENOSPC - the maximum number of memzones has already been allocated
  *    - EEXIST - a memzone with the same name already exists
@@ -294,6 +304,13 @@ int rte_ring_init(struct rte_ring *r, const char *name, unsigned count,
  */
 struct rte_ring *rte_ring_create(const char *name, unsigned count,
                                 int socket_id, unsigned flags);
+/**
+ * De-allocate all memory used by the ring.
+ *
+ * @param r
+ *   Ring to free
+ */
+void rte_ring_free(struct rte_ring *r);
 
 /**
  * Change the high water mark.
@@ -410,7 +427,7 @@ __rte_ring_mp_do_enqueue(struct rte_ring *r, void * const *obj_table,
        uint32_t cons_tail, free_entries;
        const unsigned max = n;
        int success;
-       unsigned i;
+       unsigned i, rep = 0;
        uint32_t mask = r->prod.mask;
        int ret;
 
@@ -451,7 +468,7 @@ __rte_ring_mp_do_enqueue(struct rte_ring *r, void * const *obj_table,
 
        /* write entries in ring */
        ENQUEUE_PTRS();
-       rte_compiler_barrier();
+       rte_smp_wmb();
 
        /* if we exceed the watermark */
        if (unlikely(((mask + 1) - free_entries + n) > r->prod.watermark)) {
@@ -468,9 +485,18 @@ __rte_ring_mp_do_enqueue(struct rte_ring *r, void * const *obj_table,
         * If there are other enqueues in progress that preceded us,
         * we need to wait for them to complete
         */
-       while (unlikely(r->prod.tail != prod_head))
+       while (unlikely(r->prod.tail != prod_head)) {
                rte_pause();
 
+               /* Set RTE_RING_PAUSE_REP_COUNT to avoid spin too long waiting
+                * for other thread finish. It gives pre-empted thread a chance
+                * to proceed and finish with ring dequeue operation. */
+               if (RTE_RING_PAUSE_REP_COUNT &&
+                   ++rep == RTE_RING_PAUSE_REP_COUNT) {
+                       rep = 0;
+                       sched_yield();
+               }
+       }
        r->prod.tail = prod_next;
        return ret;
 }
@@ -537,7 +563,7 @@ __rte_ring_sp_do_enqueue(struct rte_ring *r, void * const *obj_table,
 
        /* write entries in ring */
        ENQUEUE_PTRS();
-       rte_compiler_barrier();
+       rte_smp_wmb();
 
        /* if we exceed the watermark */
        if (unlikely(((mask + 1) - free_entries + n) > r->prod.watermark)) {
@@ -589,7 +615,7 @@ __rte_ring_mc_do_dequeue(struct rte_ring *r, void **obj_table,
        uint32_t cons_next, entries;
        const unsigned max = n;
        int success;
-       unsigned i;
+       unsigned i, rep = 0;
        uint32_t mask = r->prod.mask;
 
        /* move cons.head atomically */
@@ -628,15 +654,24 @@ __rte_ring_mc_do_dequeue(struct rte_ring *r, void **obj_table,
 
        /* copy in table */
        DEQUEUE_PTRS();
-       rte_compiler_barrier();
+       rte_smp_rmb();
 
        /*
         * If there are other dequeues in progress that preceded us,
         * we need to wait for them to complete
         */
-       while (unlikely(r->cons.tail != cons_head))
+       while (unlikely(r->cons.tail != cons_head)) {
                rte_pause();
 
+               /* Set RTE_RING_PAUSE_REP_COUNT to avoid spin too long waiting
+                * for other thread finish. It gives pre-empted thread a chance
+                * to proceed and finish with ring dequeue operation. */
+               if (RTE_RING_PAUSE_REP_COUNT &&
+                   ++rep == RTE_RING_PAUSE_REP_COUNT) {
+                       rep = 0;
+                       sched_yield();
+               }
+       }
        __RING_STAT_ADD(r, deq_success, n);
        r->cons.tail = cons_next;
 
@@ -703,7 +738,7 @@ __rte_ring_sc_do_dequeue(struct rte_ring *r, void **obj_table,
 
        /* copy in table */
        DEQUEUE_PTRS();
-       rte_compiler_barrier();
+       rte_smp_rmb();
 
        __RING_STAT_ADD(r, deq_success, n);
        r->cons.tail = cons_next;
@@ -1002,7 +1037,7 @@ rte_ring_full(const struct rte_ring *r)
 {
        uint32_t prod_tail = r->prod.tail;
        uint32_t cons_tail = r->cons.tail;
-       return (((cons_tail - prod_tail - 1) & r->prod.mask) == 0);
+       return ((cons_tail - prod_tail - 1) & r->prod.mask) == 0;
 }
 
 /**
@@ -1035,7 +1070,7 @@ rte_ring_count(const struct rte_ring *r)
 {
        uint32_t prod_tail = r->prod.tail;
        uint32_t cons_tail = r->cons.tail;
-       return ((prod_tail - cons_tail) & r->prod.mask);
+       return (prod_tail - cons_tail) & r->prod.mask;
 }
 
 /**
@@ -1051,7 +1086,7 @@ rte_ring_free_count(const struct rte_ring *r)
 {
        uint32_t prod_tail = r->prod.tail;
        uint32_t cons_tail = r->cons.tail;
-       return ((cons_tail - prod_tail - 1) & r->prod.mask);
+       return (cons_tail - prod_tail - 1) & r->prod.mask;
 }
 
 /**