[dpdk-stable] [PATCH v2] mem: fix allocation failure on non-NUMA kernel

[Nick Connolly]

Running dpdk-helloworld on Linux with lib numa present,
but no kernel support for NUMA (CONFIG_NUMA=n) causes
ret_service_init() to fail with EAL: error allocating
rte services array.

alloc_seg() calls get_mempolicy to verify that the allocation
has happened on the correct socket, but receives ENOSYS from
the kernel and fails the allocation.

The allocated socket should only be verified if check_numa() is true.

Fixes: 2a96c88be83e ("mem: ease init in a docker container")
Cc: nicolas.dichtel at 6wind.com
Cc: stable at dpdk.org

Signed-off-by: Nick Connolly <nick.connolly at mayadata.io>
---
v2:
* Remove unnecessary debug message and add explanatory comment

 lib/librte_eal/linux/eal_memalloc.c | 30 ++++++++++++++++++-----------
 1 file changed, 19 insertions(+), 11 deletions(-)

diff --git a/lib/librte_eal/linux/eal_memalloc.c b/lib/librte_eal/linux/eal_memalloc.c
index 40a5c4aa1..6dc1b2bae 100644
--- a/lib/librte_eal/linux/eal_memalloc.c
+++ b/lib/librte_eal/linux/eal_memalloc.c
@@ -625,17 +625,25 @@ alloc_seg(struct rte_memseg *ms, void *addr, int socket_id,
 	}
 
 #ifdef RTE_EAL_NUMA_AWARE_HUGEPAGES
-	ret = get_mempolicy(&cur_socket_id, NULL, 0, addr,
-			    MPOL_F_NODE | MPOL_F_ADDR);
-	if (ret < 0) {
-		RTE_LOG(DEBUG, EAL, "%s(): get_mempolicy: %s\n",
-			__func__, strerror(errno));
-		goto mapped;
-	} else if (cur_socket_id != socket_id) {
-		RTE_LOG(DEBUG, EAL,
-				"%s(): allocation happened on wrong socket (wanted %d, got %d)\n",
-			__func__, socket_id, cur_socket_id);
-		goto mapped;
+	/*
+	 * If the kernel has been built without NUMA support, get_mempolicy()
+	 * will return an error. If check_numa() returns false, memory
+	 * allocation is not NUMA aware and the socket_id should not be
+	 * checked.
+	 */
+	if (check_numa()) {
+		ret = get_mempolicy(&cur_socket_id, NULL, 0, addr,
+					MPOL_F_NODE | MPOL_F_ADDR);
+		if (ret < 0) {
+			RTE_LOG(DEBUG, EAL, "%s(): get_mempolicy: %s\n",
+				__func__, strerror(errno));
+			goto mapped;
+		} else if (cur_socket_id != socket_id) {
+			RTE_LOG(DEBUG, EAL,
+					"%s(): allocation happened on wrong socket (wanted %d, got %d)\n",
+				__func__, socket_id, cur_socket_id);
+			goto mapped;
+		}
 	}
 #else
 	if (rte_socket_count() > 1)
-- 
2.25.1