bql: Byte queue limits
Networking stack support for byte queue limits, uses dynamic queue
limits library. Byte queue limits are maintained per transmit queue,
and a dql structure has been added to netdev_queue structure for this
purpose.
Configuration of bql is in the tx-<n> sysfs directory for the queue
under the byte_queue_limits directory. Configuration includes:
limit_min, bql minimum limit
limit_max, bql maximum limit
hold_time, bql slack hold time
Also under the directory are:
limit, current byte limit
inflight, current number of bytes on the queue
Signed-off-by: Tom Herbert <therbert@google.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index b17c14a..3bf72b6 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -21,6 +21,7 @@
#include <linux/wireless.h>
#include <linux/vmalloc.h>
#include <linux/export.h>
+#include <linux/jiffies.h>
#include <net/wext.h>
#include "net-sysfs.h"
@@ -845,6 +846,116 @@
static struct netdev_queue_attribute queue_trans_timeout =
__ATTR(tx_timeout, S_IRUGO, show_trans_timeout, NULL);
+#ifdef CONFIG_BQL
+/*
+ * Byte queue limits sysfs structures and functions.
+ */
+static ssize_t bql_show(char *buf, unsigned int value)
+{
+ return sprintf(buf, "%u\n", value);
+}
+
+static ssize_t bql_set(const char *buf, const size_t count,
+ unsigned int *pvalue)
+{
+ unsigned int value;
+ int err;
+
+ if (!strcmp(buf, "max") || !strcmp(buf, "max\n"))
+ value = DQL_MAX_LIMIT;
+ else {
+ err = kstrtouint(buf, 10, &value);
+ if (err < 0)
+ return err;
+ if (value > DQL_MAX_LIMIT)
+ return -EINVAL;
+ }
+
+ *pvalue = value;
+
+ return count;
+}
+
+static ssize_t bql_show_hold_time(struct netdev_queue *queue,
+ struct netdev_queue_attribute *attr,
+ char *buf)
+{
+ struct dql *dql = &queue->dql;
+
+ return sprintf(buf, "%u\n", jiffies_to_msecs(dql->slack_hold_time));
+}
+
+static ssize_t bql_set_hold_time(struct netdev_queue *queue,
+ struct netdev_queue_attribute *attribute,
+ const char *buf, size_t len)
+{
+ struct dql *dql = &queue->dql;
+ unsigned value;
+ int err;
+
+ err = kstrtouint(buf, 10, &value);
+ if (err < 0)
+ return err;
+
+ dql->slack_hold_time = msecs_to_jiffies(value);
+
+ return len;
+}
+
+static struct netdev_queue_attribute bql_hold_time_attribute =
+ __ATTR(hold_time, S_IRUGO | S_IWUSR, bql_show_hold_time,
+ bql_set_hold_time);
+
+static ssize_t bql_show_inflight(struct netdev_queue *queue,
+ struct netdev_queue_attribute *attr,
+ char *buf)
+{
+ struct dql *dql = &queue->dql;
+
+ return sprintf(buf, "%u\n", dql->num_queued - dql->num_completed);
+}
+
+static struct netdev_queue_attribute bql_inflight_attribute =
+ __ATTR(inflight, S_IRUGO | S_IWUSR, bql_show_inflight, NULL);
+
+#define BQL_ATTR(NAME, FIELD) \
+static ssize_t bql_show_ ## NAME(struct netdev_queue *queue, \
+ struct netdev_queue_attribute *attr, \
+ char *buf) \
+{ \
+ return bql_show(buf, queue->dql.FIELD); \
+} \
+ \
+static ssize_t bql_set_ ## NAME(struct netdev_queue *queue, \
+ struct netdev_queue_attribute *attr, \
+ const char *buf, size_t len) \
+{ \
+ return bql_set(buf, len, &queue->dql.FIELD); \
+} \
+ \
+static struct netdev_queue_attribute bql_ ## NAME ## _attribute = \
+ __ATTR(NAME, S_IRUGO | S_IWUSR, bql_show_ ## NAME, \
+ bql_set_ ## NAME);
+
+BQL_ATTR(limit, limit)
+BQL_ATTR(limit_max, max_limit)
+BQL_ATTR(limit_min, min_limit)
+
+static struct attribute *dql_attrs[] = {
+ &bql_limit_attribute.attr,
+ &bql_limit_max_attribute.attr,
+ &bql_limit_min_attribute.attr,
+ &bql_hold_time_attribute.attr,
+ &bql_inflight_attribute.attr,
+ NULL
+};
+
+static struct attribute_group dql_group = {
+ .name = "byte_queue_limits",
+ .attrs = dql_attrs,
+};
+#endif /* CONFIG_BQL */
+
#ifdef CONFIG_XPS
static inline unsigned int get_netdev_queue_index(struct netdev_queue *queue)
{
@@ -1096,17 +1207,17 @@
NULL
};
-#ifdef CONFIG_XPS
static void netdev_queue_release(struct kobject *kobj)
{
struct netdev_queue *queue = to_netdev_queue(kobj);
+#ifdef CONFIG_XPS
xps_queue_release(queue);
+#endif
memset(kobj, 0, sizeof(*kobj));
dev_put(queue->dev);
}
-#endif /* CONFIG_XPS */
static struct kobj_type netdev_queue_ktype = {
.sysfs_ops = &netdev_queue_sysfs_ops,
@@ -1125,14 +1236,21 @@
kobj->kset = net->queues_kset;
error = kobject_init_and_add(kobj, &netdev_queue_ktype, NULL,
"tx-%u", index);
- if (error) {
- kobject_put(kobj);
- return error;
- }
+ if (error)
+ goto exit;
+
+#ifdef CONFIG_BQL
+ error = sysfs_create_group(kobj, &dql_group);
+ if (error)
+ goto exit;
+#endif
kobject_uevent(kobj, KOBJ_ADD);
dev_hold(queue->dev);
+ return 0;
+exit:
+ kobject_put(kobj);
return error;
}
#endif /* CONFIG_SYSFS */
@@ -1152,8 +1270,14 @@
}
}
- while (--i >= new_num)
- kobject_put(&net->_tx[i].kobj);
+ while (--i >= new_num) {
+ struct netdev_queue *queue = net->_tx + i;
+
+#ifdef CONFIG_BQL
+ sysfs_remove_group(&queue->kobj, &dql_group);
+#endif
+ kobject_put(&queue->kobj);
+ }
return error;
#else