devlink: Introduce new attribute 'tx_priority' to devlink-rate

To fully utilize hierarchical QoS algorithm new attribute 'tx_priority'
needs to be introduced. Priority attribute allows for usage of strict
priority arbiter among siblings. This arbitration scheme attempts to
schedule nodes based on their priority as long as the nodes remain within
their bandwidth limit.

Introduce ability to configure tx_priority from devlink userspace
utility. Make the new attribute optional.

Example commands:
$ devlink port function rate add pci/0000:4b:00.0/node_custom \
  tx_priority 5 parent node_0
$ devlink port function rate set pci/0000:4b:00.0/2 tx_priority 5

Signed-off-by: Michal Wilczynski <michal.wilczynski@intel.com>
Reviewed-by: Wojciech Drewek <wojciech.drewek@intel.com>
Signed-off-by: David Ahern <dsahern@kernel.org>

1 files changed, 28 insertions, 3 deletions

diff --git a/devlink/devlink.c b/devlink/devlink.c
index 150b4e63..5d3fd969 100644
--- a/devlink/devlink.c
+++ b/devlink/devlink.c
@@ -295,6 +295,7 @@ static void ifname_map_free(struct ifname_map *ifname_map)
 #define DL_OPT_LINECARD		BIT(52)
 #define DL_OPT_LINECARD_TYPE	BIT(53)
 #define DL_OPT_SELFTESTS	BIT(54)
+#define DL_OPT_PORT_FN_RATE_TX_PRIORITY	BIT(55)
 
 struct dl_opts {
 	uint64_t present; /* flags of present items */
@@ -353,6 +354,7 @@ struct dl_opts {
 	uint16_t rate_type;
 	uint64_t rate_tx_share;
 	uint64_t rate_tx_max;
+	uint32_t rate_tx_priority;
 	char *rate_node_name;
 	const char *rate_parent_node;
 	uint32_t linecard_index;
@@ -2067,6 +2069,13 @@ static int dl_argv_parse(struct dl *dl, uint64_t o_required,
 			if (err)
 				return err;
 			o_found |= DL_OPT_PORT_FN_RATE_TX_MAX;
+		} else if (dl_argv_match(dl, "tx_priority") &&
+			   (o_all & DL_OPT_PORT_FN_RATE_TX_PRIORITY)) {
+			dl_arg_inc(dl);
+			err = dl_argv_uint32_t(dl, &opts->rate_tx_priority);
+			if (err)
+				return err;
+			o_found |= DL_OPT_PORT_FN_RATE_TX_PRIORITY;
 		} else if (dl_argv_match(dl, "parent") &&
 			   (o_all & DL_OPT_PORT_FN_RATE_PARENT)) {
 			dl_arg_inc(dl);
@@ -2335,6 +2344,9 @@ static void dl_opts_put(struct nlmsghdr *nlh, struct dl *dl)
 	if (opts->present & DL_OPT_PORT_FN_RATE_TX_SHARE)
 		mnl_attr_put_u64(nlh, DEVLINK_ATTR_RATE_TX_SHARE,
 				 opts->rate_tx_share);
+	if (opts->present & DL_OPT_PORT_FN_RATE_TX_PRIORITY)
+		mnl_attr_put_u32(nlh, DEVLINK_ATTR_RATE_TX_PRIORITY,
+				 opts->rate_tx_priority);
 	if (opts->present & DL_OPT_PORT_FN_RATE_TX_MAX)
 		mnl_attr_put_u64(nlh, DEVLINK_ATTR_RATE_TX_MAX,
 				 opts->rate_tx_max);
@@ -4955,6 +4967,13 @@ static void pr_out_port_fn_rate(struct dl *dl, struct nlattr **tb)
 			print_rate(dl->use_iec, PRINT_ANY, "tx_max",
 				   " tx_max %s", rate);
 	}
+	if (tb[DEVLINK_ATTR_RATE_TX_PRIORITY]) {
+		uint32_t priority =
+			mnl_attr_get_u32(tb[DEVLINK_ATTR_RATE_TX_PRIORITY]);
+		if (priority)
+			print_uint(PRINT_ANY, "tx_priority",
+				   " tx_priority %u", priority);
+	}
 	if (tb[DEVLINK_ATTR_RATE_PARENT_NODE_NAME]) {
 		const char *parent =
 			mnl_attr_get_str(tb[DEVLINK_ATTR_RATE_PARENT_NODE_NAME]);
@@ -4986,11 +5005,12 @@ static void cmd_port_fn_rate_help(void)
 	pr_err("Usage: devlink port function rate help\n");
 	pr_err("       devlink port function rate show [ DEV/{ PORT_INDEX | NODE_NAME } ]\n");
 	pr_err("       devlink port function rate add DEV/NODE_NAME\n");
-	pr_err("               [ tx_share VAL ][ tx_max VAL ][ { parent NODE_NAME | noparent } ]\n");
+	pr_err("               [ tx_share VAL ][ tx_max VAL ][ tx_priority N ][ { parent NODE_NAME | noparent } ]\n");
 	pr_err("       devlink port function rate del DEV/NODE_NAME\n");
 	pr_err("       devlink port function rate set DEV/{ PORT_INDEX | NODE_NAME }\n");
-	pr_err("               [ tx_share VAL ][ tx_max VAL ][ { parent NODE_NAME | noparent } ]\n\n");
+	pr_err("               [ tx_share VAL ][ tx_max VAL ][ tx_priority N ][ { parent NODE_NAME | noparent } ]\n\n");
 	pr_err("       VAL - float or integer value in units of bits or bytes per second (bit|bps)\n");
+	pr_err("       N - integer representing priority of the node among siblings\n");
 	pr_err("       and SI (k-, m-, g-, t-) or IEC (ki-, mi-, gi-, ti-) case-insensitive prefix.\n");
 	pr_err("       Bare number, means bits per second, is possible.\n\n");
 	pr_err("       For details refer to devlink-rate(8) man page.\n");
@@ -5049,7 +5069,8 @@ static int cmd_port_fn_rate_add(struct dl *dl)
 	int err;
 
 	err = dl_argv_parse(dl, DL_OPT_PORT_FN_RATE_NODE_NAME,
-			    DL_OPT_PORT_FN_RATE_TX_SHARE | DL_OPT_PORT_FN_RATE_TX_MAX);
+			    DL_OPT_PORT_FN_RATE_TX_SHARE | DL_OPT_PORT_FN_RATE_TX_MAX |
+			    DL_OPT_PORT_FN_RATE_TX_PRIORITY);
 	if (err)
 		return err;
 
@@ -5103,6 +5124,9 @@ static int port_fn_get_rates_cb(const struct nlmsghdr *nlh, void *data)
 	if (tb[DEVLINK_ATTR_RATE_TX_MAX])
 		opts->rate_tx_max =
 			mnl_attr_get_u64(tb[DEVLINK_ATTR_RATE_TX_MAX]);
+	if (tb[DEVLINK_ATTR_RATE_TX_PRIORITY])
+		opts->rate_tx_priority =
+			mnl_attr_get_u32(tb[DEVLINK_ATTR_RATE_TX_PRIORITY]);
 	return MNL_CB_OK;
 }
 
@@ -5116,6 +5140,7 @@ static int cmd_port_fn_rate_set(struct dl *dl)
 				DL_OPT_PORT_FN_RATE_NODE_NAME,
 				DL_OPT_PORT_FN_RATE_TX_SHARE |
 				DL_OPT_PORT_FN_RATE_TX_MAX |
+				DL_OPT_PORT_FN_RATE_TX_PRIORITY |
 				DL_OPT_PORT_FN_RATE_PARENT);
 	if (err)
 		return err;