[PATCH iproute2-next 0/4] Introduce FRMR pools

[PATCH iproute2-next 0/4] Introduce FRMR pools

[Chiara Meiohas]

From Michael:

This series adds support for managing Fast Registration Memory Region
(FRMR) pools in rdma tool, enabling users to monitor and configure FRMR
pool behavior.

FRMR pools are used to cache and reuse Fast Registration Memory Region
handles to improve performance by avoiding the overhead of repeated
memory region creation and destruction. This series introduces commands
to view FRMR pool statistics and configure pool parameters such as
aging time and pinned handle count.

The 'show' command allows users to display FRMR pools created on
devices, their properties, and usage statistics. Each pool is identified
by a unique key (hex-encoded properties) for easy reference in
subsequent operations.

The aging 'set' command allows users to modify the aging time parameter,
which controls how long unused FRMR handles remain in the pool before
being released.

The pinned 'set' command allows users to configure the number of pinned
handles in a pool. Pinned handles are exempt from aging and remain
permanently available for reuse, which is useful for workloads with
predictable memory region usage patterns.

Command usage and examples are included in the commits and man pages.

Michael Guralnik (4):
  rdma: Update headers
  rdma: Add resource FRMR pools show command
  rdma: Add FRMR pools set aging command
  rdma: Add FRMR pools set pinned command

 man/man8/rdma-resource.8              |  51 +++-
 rdma/Makefile                         |   2 +-
 rdma/include/uapi/rdma/rdma_netlink.h |  22 ++
 rdma/res-frmr-pools.c                 | 342 ++++++++++++++++++++++++++
 rdma/res.c                            |  19 +-
 rdma/res.h                            |  20 ++
 6 files changed, 453 insertions(+), 3 deletions(-)
 create mode 100644 rdma/res-frmr-pools.c

-- 
2.38.1

[PATCH iproute2-next 1/4] rdma: Update headers

[Chiara Meiohas]

From: Michael Guralnik <michaelgur@nvidia.com>

Update rdma_netlink.h file up to kernel commit f55576f6ace6
("RDMA/nldev: Expose kernel-internal FRMR pools in netlink")

Signed-off-by: Michael Guralnik <michaelgur@nvidia.com>
Reviewed-by: Patrisious Haddad <phaddad@nvidia.com>
---
 rdma/include/uapi/rdma/rdma_netlink.h | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/rdma/include/uapi/rdma/rdma_netlink.h b/rdma/include/uapi/rdma/rdma_netlink.h
index ec8c19ca..dc958c8a 100644
--- a/rdma/include/uapi/rdma/rdma_netlink.h
+++ b/rdma/include/uapi/rdma/rdma_netlink.h
@@ -308,6 +308,10 @@ enum rdma_nldev_command {
 
 	RDMA_NLDEV_CMD_MONITOR,
 
+	RDMA_NLDEV_CMD_RES_FRMR_POOLS_GET, /* can dump */
+
+	RDMA_NLDEV_CMD_RES_FRMR_POOLS_SET,
+
 	RDMA_NLDEV_NUM_OPS
 };
 
@@ -582,6 +586,24 @@ enum rdma_nldev_attr {
 	RDMA_NLDEV_SYS_ATTR_MONITOR_MODE,	/* u8 */
 
 	RDMA_NLDEV_ATTR_STAT_OPCOUNTER_ENABLED,	/* u8 */
+
+	/*
+	 * FRMR Pools attributes
+	 */
+	RDMA_NLDEV_ATTR_RES_FRMR_POOLS,			/* nested table */
+	RDMA_NLDEV_ATTR_RES_FRMR_POOL_ENTRY,		/* nested table */
+	RDMA_NLDEV_ATTR_RES_FRMR_POOL_KEY,		/* nested table */
+	RDMA_NLDEV_ATTR_RES_FRMR_POOL_KEY_ATS,		/* u8 */
+	RDMA_NLDEV_ATTR_RES_FRMR_POOL_KEY_ACCESS_FLAGS,	/* u32 */
+	RDMA_NLDEV_ATTR_RES_FRMR_POOL_KEY_VENDOR_KEY,	/* u64 */
+	RDMA_NLDEV_ATTR_RES_FRMR_POOL_KEY_NUM_DMA_BLOCKS, /* u64 */
+	RDMA_NLDEV_ATTR_RES_FRMR_POOL_QUEUE_HANDLES,	/* u32 */
+	RDMA_NLDEV_ATTR_RES_FRMR_POOL_MAX_IN_USE,	/* u64 */
+	RDMA_NLDEV_ATTR_RES_FRMR_POOL_IN_USE,		/* u64 */
+	RDMA_NLDEV_ATTR_RES_FRMR_POOL_AGING_PERIOD,	/* u64 */
+	RDMA_NLDEV_ATTR_RES_FRMR_POOL_PINNED,		/* u8 */
+	RDMA_NLDEV_ATTR_RES_FRMR_POOL_KEY_KERNEL_VENDOR_KEY, /* u64 */
+
 	/*
 	 * Always the end
 	 */
-- 
2.38.1

[PATCH iproute2-next 2/4] rdma: Add resource FRMR pools show command

[Chiara Meiohas]

From: Michael Guralnik <michaelgur@nvidia.com>

Allow users to see the FRMR pools that were created on the devices,
their properties and their usage statistics.
The set of properties of each pool are encoded to a hex representation
in order to simplify referencing a specific pool in 'set' commands.

Sample output:

$rdma resource show frmr_pools
dev rocep8s0f0 key 10000000000000 queue 0 in_use 0 max_in_use 200
dev rocep8s0f0 key 8000000000000 queue 0 in_use 0 max_in_use 200
dev rocep8s0f0 key 4000000000000 queue 0 in_use 0 max_in_use 200

$rdma resource show frmr_pools -d
dev rocep8s0f0 key 10000000000000 ats 0 access_flags 0 vendor_key 0 num_dma_blocks 4096 queue 0 in_use 0 max_in_use 200
dev rocep8s0f0 key 8000000000000 ats 0 access_flags 0 vendor_key 0 num_dma_blocks 2048 queue 0 in_use 0 max_in_use 200
dev rocep8s0f0 key 4000000000000 ats 0 access_flags 0 vendor_key 0 num_dma_blocks 1024 queue 0 in_use 0 max_in_use 200

$rdma resource show frmr_pools num_dma_blocks 2048
dev rocep8s0f0 key 8000000000000 queue 0 in_use 0 max_in_use 200

Signed-off-by: Michael Guralnik <michaelgur@nvidia.com>
Reviewed-by: Patrisious Haddad <phaddad@nvidia.com>
---
 man/man8/rdma-resource.8 |   8 +-
 rdma/Makefile            |   2 +-
 rdma/res-frmr-pools.c    | 190 +++++++++++++++++++++++++++++++++++++++
 rdma/res.c               |   5 +-
 rdma/res.h               |  18 ++++
 5 files changed, 220 insertions(+), 3 deletions(-)
 create mode 100644 rdma/res-frmr-pools.c

diff --git a/man/man8/rdma-resource.8 b/man/man8/rdma-resource.8
index 61bec471..4e2ba39a 100644
--- a/man/man8/rdma-resource.8
+++ b/man/man8/rdma-resource.8
@@ -13,7 +13,8 @@ rdma-resource \- rdma resource configuration
 
 .ti -8
 .IR RESOURCE " := { "
-.BR cm_id " | " cq " | " mr " | " pd " | " qp " | " ctx " | " srq " }"
+.BR cm_id " | " cq " | " mr " | " pd " | " qp " | " ctx " | " srq " | "
+.BR frmr_pools " }"
 .sp
 
 .ti -8
@@ -113,6 +114,11 @@ rdma resource show srq lqpn 5-7
 Show SRQs that the QPs with lqpn 5-7 are associated with.
 .RE
 .PP
+rdma resource show frmr_pools ats 1
+.RS
+Show FRMR pools that have ats attribute set.
+.RE
+.PP
 
 .SH SEE ALSO
 .BR rdma (8),
diff --git a/rdma/Makefile b/rdma/Makefile
index ed3c1c1c..66fe53f9 100644
--- a/rdma/Makefile
+++ b/rdma/Makefile
@@ -5,7 +5,7 @@ CFLAGS += -I./include/uapi/
 
 RDMA_OBJ = rdma.o utils.o dev.o link.o res.o res-pd.o res-mr.o res-cq.o \
 	   res-cmid.o res-qp.o sys.o stat.o stat-mr.o res-ctx.o res-srq.o \
-	   monitor.o
+	   monitor.o res-frmr-pools.o
 
 TARGETS += rdma
 
diff --git a/rdma/res-frmr-pools.c b/rdma/res-frmr-pools.c
new file mode 100644
index 00000000..97d59705
--- /dev/null
+++ b/rdma/res-frmr-pools.c
@@ -0,0 +1,190 @@
+// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
+/*
+ * res-frmr-pools.c	RDMA tool
+ * Authors:    Michael Guralnik <michaelgur@nvidia.com>
+ */
+
+#include "res.h"
+#include <inttypes.h>
+
+#define FRMR_POOL_KEY_SIZE 21
+#define FRMR_POOL_KEY_HEX_SIZE (FRMR_POOL_KEY_SIZE * 2)
+union frmr_pool_key {
+	struct {
+		uint8_t ats;
+		uint32_t access_flags;
+		uint64_t vendor_key;
+		uint64_t num_dma_blocks;
+	} __attribute__((packed)) fields;
+	uint8_t raw[FRMR_POOL_KEY_SIZE];
+};
+
+/* Function to encode FRMR pool key to hex string (dropping leading zeros) */
+static void encode_hex_pool_key(const union frmr_pool_key *key,
+				char *hex_string)
+{
+	char temp_hex[FRMR_POOL_KEY_HEX_SIZE + 1] = { 0 };
+	int i;
+
+	for (i = 0; i < FRMR_POOL_KEY_SIZE; i++)
+		sprintf(temp_hex + (i * 2), "%02x", key->raw[i]);
+
+	for (i = 0; i < FRMR_POOL_KEY_HEX_SIZE && temp_hex[i] == '0'; i++) {
+		/* Skip leading zeros */
+	}
+
+	if (i == FRMR_POOL_KEY_HEX_SIZE) {
+		strcpy(hex_string, "0");
+		return;
+	}
+
+	strcpy(hex_string, temp_hex + i);
+}
+
+static int res_frmr_pools_line(struct rd *rd, const char *name, int idx,
+			       struct nlattr **nla_line)
+{
+	uint64_t in_use = 0, max_in_use = 0, kernel_vendor_key = 0;
+	char hex_string[FRMR_POOL_KEY_HEX_SIZE + 1] = { 0 };
+	struct nlattr *key_tb[RDMA_NLDEV_ATTR_MAX] = {};
+	union frmr_pool_key key = { 0 };
+	uint32_t queue_handles = 0;
+
+	if (nla_line[RDMA_NLDEV_ATTR_RES_FRMR_POOL_KEY]) {
+		if (mnl_attr_parse_nested(
+			    nla_line[RDMA_NLDEV_ATTR_RES_FRMR_POOL_KEY],
+			    rd_attr_cb, key_tb) != MNL_CB_OK)
+			return MNL_CB_ERROR;
+
+		if (key_tb[RDMA_NLDEV_ATTR_RES_FRMR_POOL_KEY_ATS])
+			key.fields.ats = mnl_attr_get_u8(
+				key_tb[RDMA_NLDEV_ATTR_RES_FRMR_POOL_KEY_ATS]);
+		if (key_tb[RDMA_NLDEV_ATTR_RES_FRMR_POOL_KEY_ACCESS_FLAGS])
+			key.fields.access_flags = mnl_attr_get_u32(
+				key_tb[RDMA_NLDEV_ATTR_RES_FRMR_POOL_KEY_ACCESS_FLAGS]);
+		if (key_tb[RDMA_NLDEV_ATTR_RES_FRMR_POOL_KEY_VENDOR_KEY])
+			key.fields.vendor_key = mnl_attr_get_u64(
+				key_tb[RDMA_NLDEV_ATTR_RES_FRMR_POOL_KEY_VENDOR_KEY]);
+		if (key_tb[RDMA_NLDEV_ATTR_RES_FRMR_POOL_KEY_NUM_DMA_BLOCKS])
+			key.fields.num_dma_blocks = mnl_attr_get_u64(
+				key_tb[RDMA_NLDEV_ATTR_RES_FRMR_POOL_KEY_NUM_DMA_BLOCKS]);
+		if (key_tb[RDMA_NLDEV_ATTR_RES_FRMR_POOL_KEY_KERNEL_VENDOR_KEY])
+			kernel_vendor_key = mnl_attr_get_u64(
+				key_tb[RDMA_NLDEV_ATTR_RES_FRMR_POOL_KEY_KERNEL_VENDOR_KEY]);
+
+		if (rd_is_filtered_attr(
+			    rd, "ats", key.fields.ats,
+			    key_tb[RDMA_NLDEV_ATTR_RES_FRMR_POOL_KEY_ATS]))
+			goto out;
+
+		if (rd_is_filtered_attr(
+			    rd, "access_flags", key.fields.access_flags,
+			    key_tb[RDMA_NLDEV_ATTR_RES_FRMR_POOL_KEY_ACCESS_FLAGS]))
+			goto out;
+
+		if (rd_is_filtered_attr(
+			    rd, "vendor_key", key.fields.vendor_key,
+			    key_tb[RDMA_NLDEV_ATTR_RES_FRMR_POOL_KEY_VENDOR_KEY]))
+			goto out;
+
+		if (rd_is_filtered_attr(
+			    rd, "num_dma_blocks", key.fields.num_dma_blocks,
+			    key_tb[RDMA_NLDEV_ATTR_RES_FRMR_POOL_KEY_NUM_DMA_BLOCKS]))
+			goto out;
+	}
+
+	if (nla_line[RDMA_NLDEV_ATTR_RES_FRMR_POOL_QUEUE_HANDLES])
+		queue_handles = mnl_attr_get_u32(
+			nla_line[RDMA_NLDEV_ATTR_RES_FRMR_POOL_QUEUE_HANDLES]);
+	if (rd_is_filtered_attr(
+		    rd, "queue", queue_handles,
+		    nla_line[RDMA_NLDEV_ATTR_RES_FRMR_POOL_QUEUE_HANDLES]))
+		goto out;
+
+	if (nla_line[RDMA_NLDEV_ATTR_RES_FRMR_POOL_IN_USE])
+		in_use = mnl_attr_get_u64(
+			nla_line[RDMA_NLDEV_ATTR_RES_FRMR_POOL_IN_USE]);
+	if (rd_is_filtered_attr(rd, "in_use", in_use,
+				nla_line[RDMA_NLDEV_ATTR_RES_FRMR_POOL_IN_USE]))
+		goto out;
+
+	if (nla_line[RDMA_NLDEV_ATTR_RES_FRMR_POOL_MAX_IN_USE])
+		max_in_use = mnl_attr_get_u64(
+			nla_line[RDMA_NLDEV_ATTR_RES_FRMR_POOL_MAX_IN_USE]);
+	if (rd_is_filtered_attr(
+		    rd, "max_in_use", max_in_use,
+		    nla_line[RDMA_NLDEV_ATTR_RES_FRMR_POOL_MAX_IN_USE]))
+		goto out;
+
+	open_json_object(NULL);
+	print_dev(idx, name);
+
+	if (nla_line[RDMA_NLDEV_ATTR_RES_FRMR_POOL_KEY]) {
+		encode_hex_pool_key(&key, hex_string);
+		print_string(PRINT_ANY, "key", "key %s ", hex_string);
+
+		if (rd->show_details) {
+			res_print_u32(
+				"ats", key.fields.ats,
+				key_tb[RDMA_NLDEV_ATTR_RES_FRMR_POOL_KEY_ATS]);
+			res_print_u32(
+				"access_flags", key.fields.access_flags,
+				key_tb[RDMA_NLDEV_ATTR_RES_FRMR_POOL_KEY_ACCESS_FLAGS]);
+			res_print_u64(
+				"vendor_key", key.fields.vendor_key,
+				key_tb[RDMA_NLDEV_ATTR_RES_FRMR_POOL_KEY_VENDOR_KEY]);
+			res_print_u64(
+				"num_dma_blocks", key.fields.num_dma_blocks,
+				key_tb[RDMA_NLDEV_ATTR_RES_FRMR_POOL_KEY_NUM_DMA_BLOCKS]);
+			res_print_u64(
+				"kernel_vendor_key", kernel_vendor_key,
+				key_tb[RDMA_NLDEV_ATTR_RES_FRMR_POOL_KEY_KERNEL_VENDOR_KEY]);
+		}
+	}
+
+	res_print_u32("queue", queue_handles,
+		      nla_line[RDMA_NLDEV_ATTR_RES_FRMR_POOL_QUEUE_HANDLES]);
+	res_print_u64("in_use", in_use,
+		      nla_line[RDMA_NLDEV_ATTR_RES_FRMR_POOL_IN_USE]);
+	res_print_u64("max_in_use", max_in_use,
+		      nla_line[RDMA_NLDEV_ATTR_RES_FRMR_POOL_MAX_IN_USE]);
+
+	print_driver_table(rd, nla_line[RDMA_NLDEV_ATTR_DRIVER]);
+	close_json_object();
+	newline();
+
+out:
+	return MNL_CB_OK;
+}
+
+int res_frmr_pools_parse_cb(const struct nlmsghdr *nlh, void *data)
+{
+	struct nlattr *tb[RDMA_NLDEV_ATTR_MAX] = {};
+	struct nlattr *nla_table, *nla_entry;
+	struct rd *rd = data;
+	int ret = MNL_CB_OK;
+	const char *name;
+	uint32_t idx;
+
+	mnl_attr_parse(nlh, 0, rd_attr_cb, tb);
+	if (!tb[RDMA_NLDEV_ATTR_DEV_INDEX] || !tb[RDMA_NLDEV_ATTR_DEV_NAME] ||
+	    !tb[RDMA_NLDEV_ATTR_RES_FRMR_POOLS])
+		return MNL_CB_ERROR;
+
+	name = mnl_attr_get_str(tb[RDMA_NLDEV_ATTR_DEV_NAME]);
+	idx = mnl_attr_get_u32(tb[RDMA_NLDEV_ATTR_DEV_INDEX]);
+	nla_table = tb[RDMA_NLDEV_ATTR_RES_FRMR_POOLS];
+
+	mnl_attr_for_each_nested(nla_entry, nla_table) {
+		struct nlattr *nla_line[RDMA_NLDEV_ATTR_MAX] = {};
+
+		ret = mnl_attr_parse_nested(nla_entry, rd_attr_cb, nla_line);
+		if (ret != MNL_CB_OK)
+			break;
+
+		ret = res_frmr_pools_line(rd, name, idx, nla_line);
+		if (ret != MNL_CB_OK)
+			break;
+	}
+	return ret;
+}
diff --git a/rdma/res.c b/rdma/res.c
index 7e7de042..f1f13d74 100644
--- a/rdma/res.c
+++ b/rdma/res.c
@@ -11,7 +11,7 @@ static int res_help(struct rd *rd)
 {
 	pr_out("Usage: %s resource\n", rd->filename);
 	pr_out("          resource show [DEV]\n");
-	pr_out("          resource show [qp|cm_id|pd|mr|cq|ctx|srq]\n");
+	pr_out("          resource show [qp|cm_id|pd|mr|cq|ctx|srq|frmr_pools]\n");
 	pr_out("          resource show qp link [DEV/PORT]\n");
 	pr_out("          resource show qp link [DEV/PORT] [FILTER-NAME FILTER-VALUE]\n");
 	pr_out("          resource show cm_id link [DEV/PORT]\n");
@@ -26,6 +26,8 @@ static int res_help(struct rd *rd)
 	pr_out("          resource show ctx dev [DEV] [FILTER-NAME FILTER-VALUE]\n");
 	pr_out("          resource show srq dev [DEV]\n");
 	pr_out("          resource show srq dev [DEV] [FILTER-NAME FILTER-VALUE]\n");
+	pr_out("          resource show frmr_pools dev [DEV]\n");
+	pr_out("          resource show frmr_pools dev [DEV] [FILTER-NAME FILTER-VALUE]\n");
 	return 0;
 }
 
@@ -237,6 +239,7 @@ static int res_show(struct rd *rd)
 		{ "pd",		res_pd		},
 		{ "ctx",	res_ctx		},
 		{ "srq",	res_srq		},
+		{ "frmr_pools",	res_frmr_pools	},
 		{ 0 }
 	};
 
diff --git a/rdma/res.h b/rdma/res.h
index fd09ce7d..30edb8f8 100644
--- a/rdma/res.h
+++ b/rdma/res.h
@@ -26,6 +26,8 @@ int res_ctx_parse_cb(const struct nlmsghdr *nlh, void *data);
 int res_ctx_idx_parse_cb(const struct nlmsghdr *nlh, void *data);
 int res_srq_parse_cb(const struct nlmsghdr *nlh, void *data);
 int res_srq_idx_parse_cb(const struct nlmsghdr *nlh, void *data);
+int res_frmr_pools_parse_cb(const struct nlmsghdr *nlh, void *data);
+int res_frmr_pools_idx_parse_cb(const struct nlmsghdr *nlh, void *data);
 
 static inline uint32_t res_get_command(uint32_t command, struct rd *rd)
 {
@@ -185,6 +187,22 @@ struct filters srq_valid_filters[MAX_NUMBER_OF_FILTERS] = {
 RES_FUNC(res_srq, RDMA_NLDEV_CMD_RES_SRQ_GET, srq_valid_filters, true,
 	 RDMA_NLDEV_ATTR_RES_SRQN);
 
+
+static const
+struct filters frmr_pools_valid_filters[MAX_NUMBER_OF_FILTERS] = {
+	{ .name = "dev", .is_number = false },
+	{ .name = "ats", .is_number = true },
+	{ .name = "access_flags", .is_number = true },
+	{ .name = "vendor_key", .is_number = true },
+	{ .name = "num_dma_blocks", .is_number = true },
+	{ .name = "queue", .is_number = true },
+	{ .name = "in_use", .is_number = true },
+	{ .name = "max_in_use", .is_number = true },
+};
+
+RES_FUNC(res_frmr_pools, RDMA_NLDEV_CMD_RES_FRMR_POOLS_GET,
+	 frmr_pools_valid_filters, true, 0);
+
 void print_dev(uint32_t idx, const char *name);
 void print_link(uint32_t idx, const char *name, uint32_t port, struct nlattr **nla_line);
 void print_key(const char *name, uint64_t val, struct nlattr *nlattr);
-- 
2.38.1

Re: [PATCH iproute2-next 2/4] rdma: Add resource FRMR pools show command

[David Ahern]

On 3/2/26 8:51 AM, Chiara Meiohas wrote:
> diff --git a/rdma/res-frmr-pools.c b/rdma/res-frmr-pools.c
> new file mode 100644
> index 00000000..97d59705
> --- /dev/null
> +++ b/rdma/res-frmr-pools.c
> @@ -0,0 +1,190 @@
> +// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
> +/*
> + * res-frmr-pools.c	RDMA tool
> + * Authors:    Michael Guralnik <michaelgur@nvidia.com>
> + */
> +
> +#include "res.h"
> +#include <inttypes.h>
> +
> +#define FRMR_POOL_KEY_SIZE 21
> +#define FRMR_POOL_KEY_HEX_SIZE (FRMR_POOL_KEY_SIZE * 2)
> +union frmr_pool_key {
> +	struct {
> +		uint8_t ats;
> +		uint32_t access_flags;
> +		uint64_t vendor_key;
> +		uint64_t num_dma_blocks;
> +	} __attribute__((packed)) fields;

why is packed needed on this struct? why can't the fields be re-arranged
to not require it and just let the extra 3B be at the end unused?

> +	uint8_t raw[FRMR_POOL_KEY_SIZE];
> +};
> +

Re: [PATCH iproute2-next 2/4] rdma: Add resource FRMR pools show command

[Michael Gur]

On 3/7/2026 3:45 AM, David Ahern wrote:
> External email: Use caution opening links or attachments
>
>
> On 3/2/26 8:51 AM, Chiara Meiohas wrote:
>> diff --git a/rdma/res-frmr-pools.c b/rdma/res-frmr-pools.c
>> new file mode 100644
>> index 00000000..97d59705
>> --- /dev/null
>> +++ b/rdma/res-frmr-pools.c
>> @@ -0,0 +1,190 @@
>> +// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
>> +/*
>> + * res-frmr-pools.c  RDMA tool
>> + * Authors:    Michael Guralnik <michaelgur@nvidia.com>
>> + */
>> +
>> +#include "res.h"
>> +#include <inttypes.h>
>> +
>> +#define FRMR_POOL_KEY_SIZE 21
>> +#define FRMR_POOL_KEY_HEX_SIZE (FRMR_POOL_KEY_SIZE * 2)
>> +union frmr_pool_key {
>> +     struct {
>> +             uint8_t ats;
>> +             uint32_t access_flags;
>> +             uint64_t vendor_key;
>> +             uint64_t num_dma_blocks;
>> +     } __attribute__((packed)) fields;
> why is packed needed on this struct? why can't the fields be re-arranged
> to not require it and just let the extra 3B be at the end unused?

The reasoning was to keep fields that are more likely to be zeroes at 
MSB to allow shortening the pool hex key in input and output.

Giving this another thought, I now think we're better dropping the logic 
of variable length in the pool key encoding/decoding and keep the hex 
pool key at fixed length.
I'll rearrange fields to drop the packed attribute and have the last 3B 
reserved.

>> +     uint8_t raw[FRMR_POOL_KEY_SIZE];
>> +};
>> +

[PATCH iproute2-next 3/4] rdma: Add FRMR pools set aging command

[Chiara Meiohas]

From: Michael Guralnik <michaelgur@nvidia.com>

Allow users to modify the aging time of FRMR pools.

Usage:
$rdma resource set frmr_pools dev rocep8s0f0 aging 120

Signed-off-by: Michael Guralnik <michaelgur@nvidia.com>
Reviewed-by: Patrisious Haddad <phaddad@nvidia.com>
---
 man/man8/rdma-resource.8 | 22 +++++++++++++++
 rdma/res-frmr-pools.c    | 61 ++++++++++++++++++++++++++++++++++++++++
 rdma/res.c               | 13 +++++++++
 rdma/res.h               |  1 +
 4 files changed, 97 insertions(+)

diff --git a/man/man8/rdma-resource.8 b/man/man8/rdma-resource.8
index 4e2ba39a..a6dc33f3 100644
--- a/man/man8/rdma-resource.8
+++ b/man/man8/rdma-resource.8
@@ -26,6 +26,13 @@ rdma-resource \- rdma resource configuration
 .B rdma resource show
 .RI "[ " DEV/PORT_INDEX " ]"
 
+.ti -8
+.B rdma resource set frmr_pools
+.BR dev
+.IR DEV
+.BR aging
+.IR AGING_PERIOD
+
 .ti -8
 .B rdma resource help
 
@@ -37,6 +44,16 @@ rdma-resource \- rdma resource configuration
 - specifies the RDMA link to show.
 If this argument is omitted all links are listed.
 
+.SS rdma resource set - configure resource related parameters
+
+.PP
+.I "DEV"
+- specifies the RDMA device to configure.
+
+.PP
+.I "AGING_PERIOD"
+- specifies the aging period in seconds for unused FRMR handles. Handles unused for this period will be freed.
+
 .SH "EXAMPLES"
 .PP
 rdma resource show
@@ -119,6 +136,11 @@ rdma resource show frmr_pools ats 1
 Show FRMR pools that have ats attribute set.
 .RE
 .PP
+rdma resource set frmr_pools dev rocep8s0f0 aging 120
+.RS 4
+Set the aging period for FRMR pools on device rocep8s0f0 to 120 seconds.
+.RE
+.PP
 
 .SH SEE ALSO
 .BR rdma (8),
diff --git a/rdma/res-frmr-pools.c b/rdma/res-frmr-pools.c
index 97d59705..29efb9cd 100644
--- a/rdma/res-frmr-pools.c
+++ b/rdma/res-frmr-pools.c
@@ -188,3 +188,64 @@ int res_frmr_pools_parse_cb(const struct nlmsghdr *nlh, void *data)
 	}
 	return ret;
 }
+
+static int res_frmr_pools_one_set_aging(struct rd *rd)
+{
+	uint32_t aging_period;
+	uint32_t seq;
+	int ret;
+
+	if (rd_no_arg(rd)) {
+		pr_err("Please provide aging period value.\n");
+		return -EINVAL;
+	}
+
+	if (get_u32(&aging_period, rd_argv(rd), 10)) {
+		pr_err("Invalid aging period value: %s\n", rd_argv(rd));
+		return -EINVAL;
+	}
+
+	if (aging_period == 0) {
+		pr_err("Setting the aging period to zero is not supported.\n");
+		return -EINVAL;
+	}
+
+	rd_prepare_msg(rd, RDMA_NLDEV_CMD_RES_FRMR_POOLS_SET, &seq,
+		       (NLM_F_REQUEST | NLM_F_ACK));
+	mnl_attr_put_u32(rd->nlh, RDMA_NLDEV_ATTR_DEV_INDEX, rd->dev_idx);
+	mnl_attr_put_u32(rd->nlh, RDMA_NLDEV_ATTR_RES_FRMR_POOL_AGING_PERIOD,
+			 aging_period);
+
+	ret = rd_sendrecv_msg(rd, seq);
+	return ret;
+}
+
+static int res_frmr_pools_one_set_help(struct rd *rd)
+{
+	pr_out("Usage: %s set frmr_pools dev DEV aging AGING_PERIOD\n",
+	       rd->filename);
+	return 0;
+}
+
+static int res_frmr_pools_one_set(struct rd *rd)
+{
+	const struct rd_cmd cmds[] = {
+		{ NULL, res_frmr_pools_one_set_help },
+		{ "help", res_frmr_pools_one_set_help },
+		{ "aging", res_frmr_pools_one_set_aging },
+		{ 0 }
+	};
+
+	return rd_exec_cmd(rd, cmds, "resource set frmr_pools command");
+}
+
+int res_frmr_pools_set(struct rd *rd)
+{
+	int ret;
+
+	ret = rd_set_arg_to_devname(rd);
+	if (ret)
+		return ret;
+
+	return rd_exec_require_dev(rd, res_frmr_pools_one_set);
+}
diff --git a/rdma/res.c b/rdma/res.c
index f1f13d74..63d8386a 100644
--- a/rdma/res.c
+++ b/rdma/res.c
@@ -28,6 +28,7 @@ static int res_help(struct rd *rd)
 	pr_out("          resource show srq dev [DEV] [FILTER-NAME FILTER-VALUE]\n");
 	pr_out("          resource show frmr_pools dev [DEV]\n");
 	pr_out("          resource show frmr_pools dev [DEV] [FILTER-NAME FILTER-VALUE]\n");
+	pr_out("          resource set frmr_pools dev DEV aging AGING_PERIOD\n");
 	return 0;
 }
 
@@ -252,11 +253,23 @@ static int res_show(struct rd *rd)
 	return rd_exec_cmd(rd, cmds, "parameter");
 }
 
+static int res_set(struct rd *rd)
+{
+	const struct rd_cmd cmds[] = {
+		{ NULL,		res_help },
+		{ "frmr_pools",	res_frmr_pools_set },
+		{ 0 }
+	};
+
+	return rd_exec_cmd(rd, cmds, "resource set command");
+}
+
 int cmd_res(struct rd *rd)
 {
 	const struct rd_cmd cmds[] = {
 		{ NULL,		res_show },
 		{ "show",	res_show },
+		{ "set",	res_set },
 		{ "list",	res_show },
 		{ "help",	res_help },
 		{ 0 }
diff --git a/rdma/res.h b/rdma/res.h
index 30edb8f8..dffbdb52 100644
--- a/rdma/res.h
+++ b/rdma/res.h
@@ -203,6 +203,7 @@ struct filters frmr_pools_valid_filters[MAX_NUMBER_OF_FILTERS] = {
 RES_FUNC(res_frmr_pools, RDMA_NLDEV_CMD_RES_FRMR_POOLS_GET,
 	 frmr_pools_valid_filters, true, 0);
 
+int res_frmr_pools_set(struct rd *rd);
 void print_dev(uint32_t idx, const char *name);
 void print_link(uint32_t idx, const char *name, uint32_t port, struct nlattr **nla_line);
 void print_key(const char *name, uint64_t val, struct nlattr *nlattr);
-- 
2.38.1

[PATCH iproute2-next 4/4] rdma: Add FRMR pools set pinned command

[Chiara Meiohas]

From: Michael Guralnik <michaelgur@nvidia.com>

Add an option to set the amount of pinned handles to FRMR pool.
Pinned handles are not affected by aging and stay available for reuse in
the FRMR pool.

Usage:
Set 250 pinned handles to FRMR pool with key 800000000000000 on
device rocep8s0f0
$rdma resource set frmr_pools dev rocep8s0f0 pinned 800000000000000 250

Signed-off-by: Michael Guralnik <michaelgur@nvidia.com>
Reviewed-by: Patrisious Haddad <phaddad@nvidia.com>
---
 man/man8/rdma-resource.8 | 21 +++++++++
 rdma/res-frmr-pools.c    | 93 +++++++++++++++++++++++++++++++++++++++-
 rdma/res.c               |  1 +
 rdma/res.h               |  1 +
 4 files changed, 115 insertions(+), 1 deletion(-)

diff --git a/man/man8/rdma-resource.8 b/man/man8/rdma-resource.8
index a6dc33f3..60c4024e 100644
--- a/man/man8/rdma-resource.8
+++ b/man/man8/rdma-resource.8
@@ -33,6 +33,14 @@ rdma-resource \- rdma resource configuration
 .BR aging
 .IR AGING_PERIOD
 
+.ti -8
+.B rdma resource set frmr_pools
+.BR dev
+.IR DEV
+.BR pinned
+.IR HEX_POOL_KEY
+.IR PINNED_VALUE
+
 .ti -8
 .B rdma resource help
 
@@ -54,6 +62,14 @@ If this argument is omitted all links are listed.
 .I "AGING_PERIOD"
 - specifies the aging period in seconds for unused FRMR handles. Handles unused for this period will be freed.
 
+.PP
+.I "HEX_POOL_KEY"
+- specifies the hexadecimal pool key that identifies a specific FRMR pool.
+
+.PP
+.I "PINNED_VALUE"
+- specifies the pinned value for the FRMR pool. A non-zero value pins handles to the pool, preventing them from being freed by the aging mechanism.
+
 .SH "EXAMPLES"
 .PP
 rdma resource show
@@ -141,6 +157,11 @@ rdma resource set frmr_pools dev rocep8s0f0 aging 120
 Set the aging period for FRMR pools on device rocep8s0f0 to 120 seconds.
 .RE
 .PP
+rdma resource set frmr_pools dev rocep8s0f0 pinned 1000000000000 25000
+.RS 4
+Pin 25000 handles to the FRMR pool identified by key 1000000000000 on device rocep8s0f0 to prevent them from being freed.
+.RE
+.PP
 
 .SH SEE ALSO
 .BR rdma (8),
diff --git a/rdma/res-frmr-pools.c b/rdma/res-frmr-pools.c
index 29efb9cd..01a02e47 100644
--- a/rdma/res-frmr-pools.c
+++ b/rdma/res-frmr-pools.c
@@ -41,14 +41,40 @@ static void encode_hex_pool_key(const union frmr_pool_key *key,
 	strcpy(hex_string, temp_hex + i);
 }
 
+/* Function to decode hex string to FRMR pool key */
+static int decode_hex_pool_key(const char *hex_string, union frmr_pool_key *key)
+{
+	char padded_hex[FRMR_POOL_KEY_HEX_SIZE + 1] = { 0 };
+	int len, pad_len;
+
+	len = strlen(hex_string);
+	if (len > FRMR_POOL_KEY_HEX_SIZE) {
+		pr_err("Hex pool key too long: %d (max %d characters)\n", len,
+		       FRMR_POOL_KEY_HEX_SIZE);
+		return -EINVAL;
+	}
+
+	/* Pad with leading zeros if needed */
+	pad_len = FRMR_POOL_KEY_HEX_SIZE - len;
+	memset(padded_hex, '0', pad_len);
+	strcpy(padded_hex + pad_len, hex_string);
+
+	if (hex2mem(padded_hex, key->raw, FRMR_POOL_KEY_SIZE) < 0) {
+		pr_err("Invalid hex pool key: %s\n", hex_string);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 static int res_frmr_pools_line(struct rd *rd, const char *name, int idx,
 			       struct nlattr **nla_line)
 {
 	uint64_t in_use = 0, max_in_use = 0, kernel_vendor_key = 0;
 	char hex_string[FRMR_POOL_KEY_HEX_SIZE + 1] = { 0 };
 	struct nlattr *key_tb[RDMA_NLDEV_ATTR_MAX] = {};
+	uint32_t queue_handles = 0, pinned_handles = 0;
 	union frmr_pool_key key = { 0 };
-	uint32_t queue_handles = 0;
 
 	if (nla_line[RDMA_NLDEV_ATTR_RES_FRMR_POOL_KEY]) {
 		if (mnl_attr_parse_nested(
@@ -116,6 +142,13 @@ static int res_frmr_pools_line(struct rd *rd, const char *name, int idx,
 		    nla_line[RDMA_NLDEV_ATTR_RES_FRMR_POOL_MAX_IN_USE]))
 		goto out;
 
+	if (nla_line[RDMA_NLDEV_ATTR_RES_FRMR_POOL_PINNED])
+		pinned_handles = mnl_attr_get_u32(
+			nla_line[RDMA_NLDEV_ATTR_RES_FRMR_POOL_PINNED]);
+	if (rd_is_filtered_attr(rd, "pinned", pinned_handles,
+				nla_line[RDMA_NLDEV_ATTR_RES_FRMR_POOL_PINNED]))
+		goto out;
+
 	open_json_object(NULL);
 	print_dev(idx, name);
 
@@ -148,6 +181,8 @@ static int res_frmr_pools_line(struct rd *rd, const char *name, int idx,
 		      nla_line[RDMA_NLDEV_ATTR_RES_FRMR_POOL_IN_USE]);
 	res_print_u64("max_in_use", max_in_use,
 		      nla_line[RDMA_NLDEV_ATTR_RES_FRMR_POOL_MAX_IN_USE]);
+	res_print_u32("pinned", pinned_handles,
+		      nla_line[RDMA_NLDEV_ATTR_RES_FRMR_POOL_PINNED]);
 
 	print_driver_table(rd, nla_line[RDMA_NLDEV_ATTR_DRIVER]);
 	close_json_object();
@@ -220,10 +255,65 @@ static int res_frmr_pools_one_set_aging(struct rd *rd)
 	return ret;
 }
 
+static int res_frmr_pools_one_set_pinned(struct rd *rd)
+{
+	union frmr_pool_key pool_key = { 0 };
+	struct nlattr *key_attr;
+	uint32_t pinned_value;
+	const char *hex_key;
+	uint32_t seq;
+
+	if (rd_no_arg(rd)) {
+		pr_err("Please provide pool key and pinned value.\n");
+		return -EINVAL;
+	}
+
+	hex_key = rd_argv(rd);
+	rd_arg_inc(rd);
+
+	if (decode_hex_pool_key(hex_key, &pool_key))
+		return -EINVAL;
+
+	if (rd_no_arg(rd)) {
+		pr_err("Please provide pinned value.\n");
+		return -EINVAL;
+	}
+
+	if (get_u32(&pinned_value, rd_argv(rd), 10)) {
+		pr_err("Invalid pinned value: %s\n", rd_argv(rd));
+		return -EINVAL;
+	}
+
+	rd_prepare_msg(rd, RDMA_NLDEV_CMD_RES_FRMR_POOLS_SET, &seq,
+		       (NLM_F_REQUEST | NLM_F_ACK));
+	mnl_attr_put_u32(rd->nlh, RDMA_NLDEV_ATTR_DEV_INDEX, rd->dev_idx);
+
+	mnl_attr_put_u32(rd->nlh, RDMA_NLDEV_ATTR_RES_FRMR_POOL_PINNED,
+			 pinned_value);
+
+	key_attr =
+		mnl_attr_nest_start(rd->nlh, RDMA_NLDEV_ATTR_RES_FRMR_POOL_KEY);
+	mnl_attr_put_u8(rd->nlh, RDMA_NLDEV_ATTR_RES_FRMR_POOL_KEY_ATS,
+			pool_key.fields.ats);
+	mnl_attr_put_u32(rd->nlh,
+			 RDMA_NLDEV_ATTR_RES_FRMR_POOL_KEY_ACCESS_FLAGS,
+			 pool_key.fields.access_flags);
+	mnl_attr_put_u64(rd->nlh, RDMA_NLDEV_ATTR_RES_FRMR_POOL_KEY_VENDOR_KEY,
+			 pool_key.fields.vendor_key);
+	mnl_attr_put_u64(rd->nlh,
+			 RDMA_NLDEV_ATTR_RES_FRMR_POOL_KEY_NUM_DMA_BLOCKS,
+			 pool_key.fields.num_dma_blocks);
+	mnl_attr_nest_end(rd->nlh, key_attr);
+
+	return rd_sendrecv_msg(rd, seq);
+}
+
 static int res_frmr_pools_one_set_help(struct rd *rd)
 {
 	pr_out("Usage: %s set frmr_pools dev DEV aging AGING_PERIOD\n",
 	       rd->filename);
+	pr_out("Usage: %s set frmr_pools dev DEV pinned HEX_POOL_KEY PINNED_VALUE\n",
+	       rd->filename);
 	return 0;
 }
 
@@ -233,6 +323,7 @@ static int res_frmr_pools_one_set(struct rd *rd)
 		{ NULL, res_frmr_pools_one_set_help },
 		{ "help", res_frmr_pools_one_set_help },
 		{ "aging", res_frmr_pools_one_set_aging },
+		{ "pinned", res_frmr_pools_one_set_pinned },
 		{ 0 }
 	};
 
diff --git a/rdma/res.c b/rdma/res.c
index 63d8386a..1ff257c2 100644
--- a/rdma/res.c
+++ b/rdma/res.c
@@ -29,6 +29,7 @@ static int res_help(struct rd *rd)
 	pr_out("          resource show frmr_pools dev [DEV]\n");
 	pr_out("          resource show frmr_pools dev [DEV] [FILTER-NAME FILTER-VALUE]\n");
 	pr_out("          resource set frmr_pools dev DEV aging AGING_PERIOD\n");
+	pr_out("          resource set frmr_pools dev DEV pinned HEX_POOL_KEY PINNED_VALUE\n");
 	return 0;
 }
 
diff --git a/rdma/res.h b/rdma/res.h
index dffbdb52..4758f2ea 100644
--- a/rdma/res.h
+++ b/rdma/res.h
@@ -198,6 +198,7 @@ struct filters frmr_pools_valid_filters[MAX_NUMBER_OF_FILTERS] = {
 	{ .name = "queue", .is_number = true },
 	{ .name = "in_use", .is_number = true },
 	{ .name = "max_in_use", .is_number = true },
+	{ .name = "pinned", .is_number = true },
 };
 
 RES_FUNC(res_frmr_pools, RDMA_NLDEV_CMD_RES_FRMR_POOLS_GET,
-- 
2.38.1

Re: [PATCH iproute2-next 0/4] Introduce FRMR pools

[David Ahern]

On 3/2/26 8:51 AM, Chiara Meiohas wrote:
> From Michael:
> 
> This series adds support for managing Fast Registration Memory Region
> (FRMR) pools in rdma tool, enabling users to monitor and configure FRMR
> pool behavior.
> 
> FRMR pools are used to cache and reuse Fast Registration Memory Region
> handles to improve performance by avoiding the overhead of repeated
> memory region creation and destruction. This series introduces commands
> to view FRMR pool statistics and configure pool parameters such as
> aging time and pinned handle count.
> 

reference to the kernel side patches? have those been merged?

Re: [PATCH iproute2-next 0/4] Introduce FRMR pools

[Chiara Meiohas]

On 07/03/2026 2:16, David Ahern wrote:

> On 3/2/26 8:51 AM, Chiara Meiohas wrote:
>> From Michael:
>>
>> This series adds support for managing Fast Registration Memory Region
>> (FRMR) pools in rdma tool, enabling users to monitor and configure FRMR
>> pool behavior.
>>
>> FRMR pools are used to cache and reuse Fast Registration Memory Region
>> handles to improve performance by avoiding the overhead of repeated
>> memory region creation and destruction. This series introduces commands
>> to view FRMR pool statistics and configure pool parameters such as
>> aging time and pinned handle count.
>>
> reference to the kernel side patches? have those been merged?
>
yes - the kernel patches have been merged:

https://lore.kernel.org/linux-rdma/20260226-frmr_pools-v4-0-95360b54f15e@nvidia.com/

Regarding the other comments, we're looking into them and will address them soon


Thanks,

Chiara

Re: [PATCH iproute2-next 0/4] Introduce FRMR pools

[David Ahern]

On 3/2/26 8:51 AM, Chiara Meiohas wrote:
> From Michael:
> 
> This series adds support for managing Fast Registration Memory Region
> (FRMR) pools in rdma tool, enabling users to monitor and configure FRMR
> pool behavior.
> 

Claude has some quibbles with the patches:


1. Type mismatch: RDMA_NLDEV_ATTR_RES_FRMR_POOL_AGING_PERIOD

In rdma/include/uapi/rdma/rdma_netlink.h:
> +     RDMA_NLDEV_ATTR_RES_FRMR_POOL_AGING_PERIOD,     /* u64 */

In rdma/res-frmr-pools.c (res_frmr_pools_one_set_aging):
> +     uint32_t aging_period;
> +     mnl_attr_put_u32(rd->nlh,
RDMA_NLDEV_ATTR_RES_FRMR_POOL_AGING_PERIOD,
> +                      aging_period);

The uapi header documents this attribute as u64, but the code declares a
uint32_t variable and sends it with mnl_attr_put_u32(). This mismatch
means userspace will send a 4-byte attribute when the kernel expects 8
bytes, leading to either a parse error or silent data truncation.

Fix: use uint64_t and mnl_attr_put_u64() to match the uapi annotation,
or correct the uapi comment to reflect the intended wire type.

---

2. Type mismatch: RDMA_NLDEV_ATTR_RES_FRMR_POOL_PINNED

In rdma/include/uapi/rdma/rdma_netlink.h:
> +     RDMA_NLDEV_ATTR_RES_FRMR_POOL_PINNED,           /* u8 */

In rdma/res-frmr-pools.c (res_frmr_pools_line):
> +     uint32_t queue_handles = 0, pinned_handles = 0;
> +     if (nla_line[RDMA_NLDEV_ATTR_RES_FRMR_POOL_PINNED])
> +             pinned_handles = mnl_attr_get_u32(
> +                     nla_line[RDMA_NLDEV_ATTR_RES_FRMR_POOL_PINNED]);

In rdma/res-frmr-pools.c (res_frmr_pools_one_set_pinned):
> +     uint32_t pinned_value;
> +     mnl_attr_put_u32(rd->nlh, RDMA_NLDEV_ATTR_RES_FRMR_POOL_PINNED,
> +                      pinned_value);

The uapi header marks this as u8, but the code reads and writes it as u32
using mnl_attr_get_u32() and mnl_attr_put_u32(). The type used in
userspace must match the kernel's attribute definition.

Fix: decide on the actual wire type and make the uapi comment, variable
declaration, and mnl accessor consistent. If u32 is correct, change the
comment to /* u32 */; if u8 is correct, use uint8_t and mnl_attr_put_u8().

---

3. Declared but unimplemented: res_frmr_pools_idx_parse_cb

In rdma/res.h:
> +int res_frmr_pools_idx_parse_cb(const struct nlmsghdr *nlh, void *data);

This function is declared alongside all the other *_idx_parse_cb symbols,
but there is no corresponding definition in rdma/res-frmr-pools.c.

Because res_frmr_pools uses id=0 in RES_FUNC:
> +RES_FUNC(res_frmr_pools, RDMA_NLDEV_CMD_RES_FRMR_POOLS_GET,
> +      frmr_pools_valid_filters, true, 0);

the macro's idx path is never triggered, so this won't cause a link error
in practice. However, the declaration is misleading and inconsistent with
the other resource types where the idx callback exists because they pass a
non-zero id. Either implement the function (if per-index lookup is
planned) or remove the declaration from res.h.

---

Re: [PATCH iproute2-next 0/4] Introduce FRMR pools

[Michael Gur]

On 3/7/2026 3:45 AM, David Ahern wrote:
> External email: Use caution opening links or attachments
>
>
> On 3/2/26 8:51 AM, Chiara Meiohas wrote:
>>  From Michael:
>>
>> This series adds support for managing Fast Registration Memory Region
>> (FRMR) pools in rdma tool, enabling users to monitor and configure FRMR
>> pool behavior.
>>
> Claude has some quibbles with the patches:
>
>
> 1. Type mismatch: RDMA_NLDEV_ATTR_RES_FRMR_POOL_AGING_PERIOD
>
>
> 2. Type mismatch: RDMA_NLDEV_ATTR_RES_FRMR_POOL_PINNED
>
Ack, wrong types in the header comments.
> 3. Declared but unimplemented: res_frmr_pools_idx_parse_cb

Ack, this could use a stub definition. Similar to res_no_args.

Thanks