Parse the new RDMA_NLDEV_ATTR_RES_SUMMARY_ENTRY_MAX netlink attribute
to show resource usage percentage alongside current counts:

  Before: 0: mlx5_0: qp 123  cq 45  mr 200  pd 10
  After:  0: mlx5_0: qp 123 (0.0%)  cq 45 (0.0%)  mr 200 (0.0%)  pd 10 (0.0%)

JSON output gains "max" and "usage" fields per resource type.
Backward compatible: no output change when kernel lacks the new attribute.

Link: https://lore.kernel.org/all/20260423061352.359749-1-cuitao@kylinos.cn/

Signed-off-by: Tao Cui <cuitao@kylinos.cn>
---
 rdma/include/uapi/rdma/rdma_netlink.h |  5 +++++
 rdma/res.c                            | 15 +++++++++++++++
 rdma/utils.c                          |  1 +
 3 files changed, 21 insertions(+)

diff --git a/rdma/include/uapi/rdma/rdma_netlink.h b/rdma/include/uapi/rdma/rdma_netlink.h
index 8709e558..12ca07ef 100644
--- a/rdma/include/uapi/rdma/rdma_netlink.h
+++ b/rdma/include/uapi/rdma/rdma_netlink.h
@@ -604,6 +604,11 @@ enum rdma_nldev_attr {
 	RDMA_NLDEV_ATTR_RES_FRMR_POOL_PINNED,		/* u32 */
 	RDMA_NLDEV_ATTR_RES_FRMR_POOL_KEY_KERNEL_VENDOR_KEY, /* u64 */
 
+	/*
+	 * Resource summary entry maximum value, used to calculate usage rate.
+	 */
+	RDMA_NLDEV_ATTR_RES_SUMMARY_ENTRY_MAX,		/* u64 */
+
 	/*
 	 * Always the end
 	 */
diff --git a/rdma/res.c b/rdma/res.c
index 062f0007..cf9c79a3 100644
--- a/rdma/res.c
+++ b/rdma/res.c
@@ -56,6 +56,21 @@ static int res_print_summary(struct nlattr **tb)
 		name = mnl_attr_get_str(nla_line[RDMA_NLDEV_ATTR_RES_SUMMARY_ENTRY_NAME]);
 		curr = mnl_attr_get_u64(nla_line[RDMA_NLDEV_ATTR_RES_SUMMARY_ENTRY_CURR]);
 		res_print_u64(name, curr, nla_line[RDMA_NLDEV_ATTR_RES_SUMMARY_ENTRY_CURR]);
+
+		if (nla_line[RDMA_NLDEV_ATTR_RES_SUMMARY_ENTRY_MAX]) {
+			uint64_t max;
+
+			max = mnl_attr_get_u64(
+				nla_line[RDMA_NLDEV_ATTR_RES_SUMMARY_ENTRY_MAX]);
+			print_u64(PRINT_JSON, "max", NULL, max);
+			if (max > 0) {
+				char usage_str[32];
+
+				snprintf(usage_str, sizeof(usage_str), "(%.1f%%)",
+					 (double)curr * 100.0 / (double)max);
+				print_string(PRINT_ANY, "usage", "%s ", usage_str);
+			}
+		}
 	}
 	return 0;
 }
diff --git a/rdma/utils.c b/rdma/utils.c
index 87003b2c..90ea1c55 100644
--- a/rdma/utils.c
+++ b/rdma/utils.c
@@ -480,6 +480,7 @@ static const enum mnl_attr_data_type nldev_policy[RDMA_NLDEV_ATTR_MAX] = {
 	[RDMA_NLDEV_ATTR_EVENT_TYPE] = MNL_TYPE_U8,
 	[RDMA_NLDEV_SYS_ATTR_MONITOR_MODE] = MNL_TYPE_U8,
 	[RDMA_NLDEV_ATTR_STAT_OPCOUNTER_ENABLED] = MNL_TYPE_U8,
+	[RDMA_NLDEV_ATTR_RES_SUMMARY_ENTRY_MAX] = MNL_TYPE_U64,
 };
 
 static int rd_attr_check(const struct nlattr *attr, int *typep)
-- 
2.43.0