[dpdk-dev] [PATCH v2] mempool: fix alignment of memzone length when populating

[Olivier Matz <olivier.matz@6wind.com>]

When populating a mempool with the default function, if there is not
enough virtually contiguous memory for the whole mempool, it will be
populated with several chunks. A chunk of the maximum available length
is requested with:

  mz = rte_memzone_reserve_aligned(..., len=0, ..., align=x)

If align is smaller than the page size, the address and the length of
the memzone may not be a multiple of the page size. This makes
rte_mempool_populate_virt() to fail because it requires them to be
page-aligned. This patch fixes that.

The problem can be reproduced easily by allocating more than available
memory:
  ./build/app/testpmd -l 0,1 -- --total-num-mbufs=65536
  ...
  Cause: Creation of mbuf pool for socket 0 failed: Invalid argument

After the patch, the error code is correct:
  ./build/app/testpmd -l 0,1 -- --total-num-mbufs=65536
  ...
  Cause: Creation of mbuf pool for socket 0 failed: Cannot allocate memory

Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
Fixes: ba0009560c30 ("mempool: support new allocation methods")
Acked-by: Anatoly Burakov <anatoly.burakov@intel.com>
---

v2:
* ensure that both address and length are page-aligned, as suggested by
  Andrew


 lib/librte_mempool/rte_mempool.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/lib/librte_mempool/rte_mempool.c b/lib/librte_mempool/rte_mempool.c
index cf5d124ec..9f1a4253b 100644
--- a/lib/librte_mempool/rte_mempool.c
+++ b/lib/librte_mempool/rte_mempool.c
@@ -684,7 +684,8 @@ 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, flags,
+					RTE_MAX(pg_sz, align));
 		}
 		if (mz == NULL) {
 			ret = -rte_errno;
@@ -709,7 +710,7 @@ rte_mempool_populate_default(struct rte_mempool *mp)
 				(void *)(uintptr_t)mz);
 		else
 			ret = rte_mempool_populate_virt(mp, mz->addr,
-				mz->len, pg_sz,
+				RTE_ALIGN_FLOOR(mz->len, pg_sz), pg_sz,
 				rte_mempool_memchunk_mz_free,
 				(void *)(uintptr_t)mz);
 		if (ret < 0) {
-- 
2.11.0