[PATCH 2/4] common/mlx5: release unused mempool entries

[PATCH 2/4] common/mlx5: release unused mempool entries

[Bing Zhao]

From: Roi Dayan <roid@nvidia.com>

When creating a new mempool but assigning a shared entries
from a different mempool need to release the newly unused
allocated entries. Fix it.

Fixes: 8947eebc999e ("common/mlx5: fix shared memory region ranges allocation")
Cc: bingz@nvidia.com

Signed-off-by: Roi Dayan <roid@nvidia.com>
Signed-off-by: Gregory Etelson <getelson@nvidia.com>
---
 drivers/common/mlx5/mlx5_common_mr.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/common/mlx5/mlx5_common_mr.c b/drivers/common/mlx5/mlx5_common_mr.c
index c41ffff2d5..8ed988dec9 100644
--- a/drivers/common/mlx5/mlx5_common_mr.c
+++ b/drivers/common/mlx5/mlx5_common_mr.c
@@ -1717,18 +1717,24 @@ mlx5_mr_mempool_register_primary(struct mlx5_mr_share_cache *share_cache,
 	 * hugepage can be shared across mempools that also fit in it.
 	 */
 	if (share_hugepage) {
+		struct mlx5_mempool_mr *gc_mrs = NULL;
+
 		rte_rwlock_write_lock(&share_cache->rwlock);
 		LIST_FOREACH(mpr, &share_cache->mempool_reg_list, next) {
 			if (mpr->mrs[0].pmd_mr.addr == (void *)ranges[0].start)
 				break;
 		}
 		if (mpr != NULL) {
+			/* Releasing MRs here can create a dead-lock on share_cache->rwlock */
+			gc_mrs = new_mpr->mrs;
 			new_mpr->mrs = mpr->mrs;
 			mlx5_mempool_reg_attach(new_mpr);
 			LIST_INSERT_HEAD(&share_cache->mempool_reg_list,
 					 new_mpr, next);
 		}
 		rte_rwlock_write_unlock(&share_cache->rwlock);
+		if (gc_mrs != NULL)
+			mlx5_free(gc_mrs);
 		if (mpr != NULL) {
 			DRV_LOG(DEBUG, "Shared MR %#x in PD %p for mempool %s with mempool %s",
 				mpr->mrs[0].pmd_mr.lkey, pd, mp->name,
-- 
2.34.1

RE: [PATCH 2/4] common/mlx5: release unused mempool entries

[Suanming Mou]

> -----Original Message-----
> From: Bing Zhao <bingz@nvidia.com>
> Sent: Wednesday, November 12, 2025 3:42 PM
> To: Slava Ovsiienko <viacheslavo@nvidia.com>; dev@dpdk.org; Raslan
> Darawsheh <rasland@nvidia.com>
> Cc: Ori Kam <orika@nvidia.com>; Dariusz Sosnowski
> <dsosnowski@nvidia.com>; Suanming Mou <suanmingm@nvidia.com>;
> Matan Azrad <matan@nvidia.com>; NBU-Contact-Thomas Monjalon
> (EXTERNAL) <thomas@monjalon.net>; Bing Zhao <bingz@nvidia.com>; Roi
> Dayan <roid@nvidia.com>; Gregory Etelson <getelson@nvidia.com>
> Subject: [PATCH 2/4] common/mlx5: release unused mempool entries
> 
> From: Roi Dayan <roid@nvidia.com>
> 
> When creating a new mempool but assigning a shared entries from a different
> mempool need to release the newly unused allocated entries. Fix it.
> 
> Fixes: 8947eebc999e ("common/mlx5: fix shared memory region ranges
> allocation")
> Cc: bingz@nvidia.com
> 
> Signed-off-by: Roi Dayan <roid@nvidia.com>
> Signed-off-by: Gregory Etelson <getelson@nvidia.com>
Acked-by: Suanming Mou <suanmingm@nvidia.com>