/* true if x is a power of 2 */
#define POWEROF2(x) ((((x)-1) & (x)) == 0)
+/* by default set head/tail distance as 1/8 of ring capacity */
+#define HTD_MAX_DEF 8
+
/* return the size of memory occupied by a ring */
ssize_t
rte_ring_get_memsize_elem(unsigned int esize, unsigned int count)
return rte_ring_get_memsize_elem(sizeof(void *), count);
}
+/*
+ * internal helper function to reset prod/cons head-tail values.
+ */
+static void
+reset_headtail(void *p)
+{
+ struct rte_ring_headtail *ht;
+ struct rte_ring_rts_headtail *ht_rts;
+
+ ht = p;
+ ht_rts = p;
+
+ switch (ht->sync_type) {
+ case RTE_RING_SYNC_MT:
+ case RTE_RING_SYNC_ST:
+ ht->head = 0;
+ ht->tail = 0;
+ break;
+ case RTE_RING_SYNC_MT_RTS:
+ ht_rts->head.raw = 0;
+ ht_rts->tail.raw = 0;
+ break;
+ default:
+ /* unknown sync mode */
+ RTE_ASSERT(0);
+ }
+}
+
void
rte_ring_reset(struct rte_ring *r)
{
- r->prod.head = r->cons.head = 0;
- r->prod.tail = r->cons.tail = 0;
+ reset_headtail(&r->prod);
+ reset_headtail(&r->cons);
+}
+
+/*
+ * helper function, calculates sync_type values for prod and cons
+ * based on input flags. Returns zero at success or negative
+ * errno value otherwise.
+ */
+static int
+get_sync_type(uint32_t flags, enum rte_ring_sync_type *prod_st,
+ enum rte_ring_sync_type *cons_st)
+{
+ static const uint32_t prod_st_flags =
+ (RING_F_SP_ENQ | RING_F_MP_RTS_ENQ);
+ static const uint32_t cons_st_flags =
+ (RING_F_SC_DEQ | RING_F_MC_RTS_DEQ);
+
+ switch (flags & prod_st_flags) {
+ case 0:
+ *prod_st = RTE_RING_SYNC_MT;
+ break;
+ case RING_F_SP_ENQ:
+ *prod_st = RTE_RING_SYNC_ST;
+ break;
+ case RING_F_MP_RTS_ENQ:
+ *prod_st = RTE_RING_SYNC_MT_RTS;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ switch (flags & cons_st_flags) {
+ case 0:
+ *cons_st = RTE_RING_SYNC_MT;
+ break;
+ case RING_F_SC_DEQ:
+ *cons_st = RTE_RING_SYNC_ST;
+ break;
+ case RING_F_MC_RTS_DEQ:
+ *cons_st = RTE_RING_SYNC_MT_RTS;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
}
int
RTE_BUILD_BUG_ON((offsetof(struct rte_ring, prod) &
RTE_CACHE_LINE_MASK) != 0);
+ RTE_BUILD_BUG_ON(offsetof(struct rte_ring_headtail, sync_type) !=
+ offsetof(struct rte_ring_rts_headtail, sync_type));
+ RTE_BUILD_BUG_ON(offsetof(struct rte_ring_headtail, tail) !=
+ offsetof(struct rte_ring_rts_headtail, tail.val.pos));
+
/* init the ring structure */
memset(r, 0, sizeof(*r));
ret = strlcpy(r->name, name, sizeof(r->name));
if (ret < 0 || ret >= (int)sizeof(r->name))
return -ENAMETOOLONG;
r->flags = flags;
- r->prod.sync_type = (flags & RING_F_SP_ENQ) ?
- RTE_RING_SYNC_ST : RTE_RING_SYNC_MT;
- r->cons.sync_type = (flags & RING_F_SC_DEQ) ?
- RTE_RING_SYNC_ST : RTE_RING_SYNC_MT;
+ ret = get_sync_type(flags, &r->prod.sync_type, &r->cons.sync_type);
+ if (ret != 0)
+ return ret;
if (flags & RING_F_EXACT_SZ) {
r->size = rte_align32pow2(count + 1);
r->mask = count - 1;
r->capacity = r->mask;
}
- r->prod.head = r->cons.head = 0;
- r->prod.tail = r->cons.tail = 0;
+
+ /* set default values for head-tail distance */
+ if (flags & RING_F_MP_RTS_ENQ)
+ rte_ring_set_prod_htd_max(r, r->capacity / HTD_MAX_DEF);
+ if (flags & RING_F_MC_RTS_DEQ)
+ rte_ring_set_cons_htd_max(r, r->capacity / HTD_MAX_DEF);
return 0;
}