mbuf: provide bulk allocation

[dpdk.git] / lib / librte_mbuf / rte_mbuf.h

diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
index c973e9b..c1f6bc4 100644 (file)
--- a/lib/librte_mbuf/rte_mbuf.h
+++ b/lib/librte_mbuf/rte_mbuf.h
@@ -1335,6 +1335,61 @@ static inline struct rte_mbuf *rte_pktmbuf_alloc(struct rte_mempool *mp)
        return m;
 }
 
+/**
+ * Allocate a bulk of mbufs, initialize refcnt and reset the fields to default
+ * values.
+ *
+ *  @param pool
+ *    The mempool from which mbufs are allocated.
+ *  @param mbufs
+ *    Array of pointers to mbufs
+ *  @param count
+ *    Array size
+ *  @return
+ *   - 0: Success
+ */
+static inline int rte_pktmbuf_alloc_bulk(struct rte_mempool *pool,
+        struct rte_mbuf **mbufs, unsigned count)
+{
+       unsigned idx = 0;
+       int rc;
+
+       rc = rte_mempool_get_bulk(pool, (void **)mbufs, count);
+       if (unlikely(rc))
+               return rc;
+
+       /* To understand duff's device on loop unwinding optimization, see
+        * https://en.wikipedia.org/wiki/Duff's_device.
+        * Here while() loop is used rather than do() while{} to avoid extra
+        * check if count is zero.
+        */
+       switch (count % 4) {
+       case 0:
+               while (idx != count) {
+                       RTE_MBUF_ASSERT(rte_mbuf_refcnt_read(mbufs[idx]) == 0);
+                       rte_mbuf_refcnt_set(mbufs[idx], 1);
+                       rte_pktmbuf_reset(mbufs[idx]);
+                       idx++;
+       case 3:
+                       RTE_MBUF_ASSERT(rte_mbuf_refcnt_read(mbufs[idx]) == 0);
+                       rte_mbuf_refcnt_set(mbufs[idx], 1);
+                       rte_pktmbuf_reset(mbufs[idx]);
+                       idx++;
+       case 2:
+                       RTE_MBUF_ASSERT(rte_mbuf_refcnt_read(mbufs[idx]) == 0);
+                       rte_mbuf_refcnt_set(mbufs[idx], 1);
+                       rte_pktmbuf_reset(mbufs[idx]);
+                       idx++;
+       case 1:
+                       RTE_MBUF_ASSERT(rte_mbuf_refcnt_read(mbufs[idx]) == 0);
+                       rte_mbuf_refcnt_set(mbufs[idx], 1);
+                       rte_pktmbuf_reset(mbufs[idx]);
+                       idx++;
+               }
+       }
+       return 0;
+}
+
 /**
  * Attach packet mbuf to another packet mbuf.
  *