mempool: remove optimistic IOVA-contiguous allocation

The previous commit reduced the amount of required memory when
populating the mempool with non IOVA-contiguous memory.

Since there is no big advantage to have a fully iova-contiguous mempool
if it is not explicitly asked, remove this code, it simplifies the
populate function.

Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
Reviewed-by: Andrew Rybchenko <arybchenko@solarflare.com>
Acked-by: Nipun Gupta <nipun.gupta@nxp.com>

diff --git a/lib/librte_mempool/rte_mempool.c b/lib/librte_mempool/rte_mempool.c
index 4e0d576..213e574 100644 (file)
--- a/lib/librte_mempool/rte_mempool.c
+++ b/lib/librte_mempool/rte_mempool.c
@@ -430,7 +430,6 @@ rte_mempool_populate_default(struct rte_mempool *mp)
        unsigned mz_id, n;
        int ret;
        bool need_iova_contig_obj;
-       bool try_iova_contig_mempool;
        bool alloc_in_ext_mem;
 
        ret = mempool_ops_alloc_once(mp);
@@ -483,9 +482,7 @@ rte_mempool_populate_default(struct rte_mempool *mp)
         * We also have to take into account the fact that memory that we're
         * going to allocate from can belong to an externally allocated memory
         * area, in which case the assumption of IOVA as VA mode being
-        * synonymous with IOVA contiguousness will not hold. We should also try
-        * to go for contiguous memory even if we're in no-huge mode, because
-        * external memory may in fact be IOVA-contiguous.
+        * synonymous with IOVA contiguousness will not hold.
         */
 
        /* check if we can retrieve a valid socket ID */
@@ -494,7 +491,6 @@ rte_mempool_populate_default(struct rte_mempool *mp)
                return -EINVAL;
        alloc_in_ext_mem = (ret == 1);
        need_iova_contig_obj = !(mp->flags & MEMPOOL_F_NO_IOVA_CONTIG);
-       try_iova_contig_mempool = false;
 
        if (!need_iova_contig_obj) {
                pg_sz = 0;
@@ -503,7 +499,6 @@ rte_mempool_populate_default(struct rte_mempool *mp)
                pg_sz = 0;
                pg_shift = 0;
        } else if (rte_eal_has_hugepages() || alloc_in_ext_mem) {
-               try_iova_contig_mempool = true;
                pg_sz = get_min_page_size(mp->socket_id);
                pg_shift = rte_bsf32(pg_sz);
        } else {
@@ -513,14 +508,9 @@ rte_mempool_populate_default(struct rte_mempool *mp)
 
        for (mz_id = 0, n = mp->size; n > 0; mz_id++, n -= ret) {
                size_t min_chunk_size;
-               unsigned int flags;
 
-               if (try_iova_contig_mempool || pg_sz == 0)
-                       mem_size = rte_mempool_ops_calc_mem_size(mp, n,
-                                       0, &min_chunk_size, &align);
-               else
-                       mem_size = rte_mempool_ops_calc_mem_size(mp, n,
-                                       pg_shift, &min_chunk_size, &align);
+               mem_size = rte_mempool_ops_calc_mem_size(
+                       mp, n, pg_shift, &min_chunk_size, &align);
 
                if (mem_size < 0) {
                        ret = mem_size;
@@ -534,36 +524,15 @@ rte_mempool_populate_default(struct rte_mempool *mp)
                        goto fail;
                }
 
-               flags = mz_flags;
-
                /* if we're trying to reserve contiguous memory, add appropriate
                 * memzone flag.
                 */
-               if (try_iova_contig_mempool)
-                       flags |= RTE_MEMZONE_IOVA_CONTIG;
+               if (min_chunk_size == (size_t)mem_size)
+                       mz_flags |= RTE_MEMZONE_IOVA_CONTIG;
 
                mz = rte_memzone_reserve_aligned(mz_name, mem_size,
-                               mp->socket_id, flags, align);
-
-               /* if we were trying to allocate contiguous memory, failed and
-                * minimum required contiguous chunk fits minimum page, adjust
-                * memzone size to the page size, and try again.
-                */
-               if (mz == NULL && try_iova_contig_mempool &&
-                               min_chunk_size <= pg_sz) {
-                       try_iova_contig_mempool = false;
-                       flags &= ~RTE_MEMZONE_IOVA_CONTIG;
-
-                       mem_size = rte_mempool_ops_calc_mem_size(mp, n,
-                                       pg_shift, &min_chunk_size, &align);
-                       if (mem_size < 0) {
-                               ret = mem_size;
-                               goto fail;
-                       }
+                               mp->socket_id, mz_flags, align);
 
-                       mz = rte_memzone_reserve_aligned(mz_name, mem_size,
-                               mp->socket_id, flags, align);
-               }
                /* don't try reserving with 0 size if we were asked to reserve
                 * IOVA-contiguous memory.
                 */
@@ -572,7 +541,7 @@ rte_mempool_populate_default(struct rte_mempool *mp)
                         * have
                         */
                        mz = rte_memzone_reserve_aligned(mz_name, 0,
-                                       mp->socket_id, flags, align);
+                                       mp->socket_id, mz_flags, align);
                }
                if (mz == NULL) {
                        ret = -rte_errno;
@@ -590,7 +559,7 @@ rte_mempool_populate_default(struct rte_mempool *mp)
                else
                        iova = RTE_BAD_IOVA;
 
-               if (try_iova_contig_mempool || pg_sz == 0)
+               if (pg_sz == 0 || (mz_flags & RTE_MEMZONE_IOVA_CONTIG))
                        ret = rte_mempool_populate_iova(mp, mz->addr,
                                iova, mz->len,
                                rte_mempool_memchunk_mz_free,