* [PATCH net 1/2] net/sched: taprio: fix picos_per_byte miscalculation
2019-03-13 22:43 [PATCH net 0/2] net/sched: taprio: cbs: Fix using invalid link speed Leandro Dorileo
@ 2019-03-13 22:43 ` Leandro Dorileo
2019-03-14 16:08 ` kbuild test robot
2019-03-14 16:21 ` kbuild test robot
2019-03-13 22:43 ` [PATCH net 2/2] net/sched: cbs: fix port_rate miscalculation Leandro Dorileo
1 sibling, 2 replies; 6+ messages in thread
From: Leandro Dorileo @ 2019-03-13 22:43 UTC (permalink / raw)
To: netdev
Cc: Jamal Hadi Salim, Cong Wang, Jiri Pirko, David S . Miller,
Vinicius Costa Gomes
The Time Aware Priority Scheduler is heavily dependent to link speed,
it relies on it to calculate transmission bytes per cycle, we can't
properly calculate the so called budget if the device has failed
to report the link speed.
In that case we can't dequeue packets assuming a wrong budget.
This patch makes sure we fail to dequeue case:
1) __ethtool_get_link_ksettings() reports error or 2) the ethernet
driver failed to set the ksettings' speed value (setting link speed
to SPEED_UNKNOWN).
Additionally we re calculate the budget whenever the link speed is
changed.
Fixes: 5a781ccbd19e4 ("tc: Add support for configuring the taprio scheduler")
Signed-off-by: Leandro Dorileo <leandro.maciel.dorileo@intel.com>
---
net/sched/sch_taprio.c | 90 ++++++++++++++++++++++++++++++++++--------
1 file changed, 74 insertions(+), 16 deletions(-)
diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c
index 206e4dbed12f..20c7a6779cc9 100644
--- a/net/sched/sch_taprio.c
+++ b/net/sched/sch_taprio.c
@@ -20,6 +20,9 @@
#include <net/pkt_cls.h>
#include <net/sch_generic.h>
+static LIST_HEAD(taprio_list);
+static DEFINE_SPINLOCK(taprio_list_lock);
+
#define TAPRIO_ALL_GATES_OPEN -1
struct sched_entry {
@@ -42,9 +45,9 @@ struct taprio_sched {
struct Qdisc *root;
s64 base_time;
int clockid;
- int picos_per_byte; /* Using picoseconds because for 10Gbps+
- * speeds it's sub-nanoseconds per byte
- */
+ atomic64_t picos_per_byte; /* Using picoseconds because for 10Gbps+
+ * speeds it's sub-nanoseconds per byte
+ */
size_t num_entries;
/* Protects the update side of the RCU protected current_entry */
@@ -53,6 +56,7 @@ struct taprio_sched {
struct list_head entries;
ktime_t (*get_time)(void);
struct hrtimer advance_timer;
+ struct list_head taprio_list;
};
static int taprio_enqueue(struct sk_buff *skb, struct Qdisc *sch,
@@ -117,7 +121,7 @@ static struct sk_buff *taprio_peek(struct Qdisc *sch)
static inline int length_to_duration(struct taprio_sched *q, int len)
{
- return (len * q->picos_per_byte) / 1000;
+ return (len * atomic64_read(&q->picos_per_byte)) / 1000;
}
static struct sk_buff *taprio_dequeue(struct Qdisc *sch)
@@ -129,6 +133,11 @@ static struct sk_buff *taprio_dequeue(struct Qdisc *sch)
u32 gate_mask;
int i;
+ if (atomic64_read(&q->picos_per_byte) == -1) {
+ WARN_ONCE(1, "taprio: dequeue() called with unknown picos per byte.");
+ return NULL;
+ }
+
rcu_read_lock();
entry = rcu_dereference(q->current_entry);
/* if there's no entry, it means that the schedule didn't
@@ -233,7 +242,7 @@ static enum hrtimer_restart advance_sched(struct hrtimer *timer)
next->close_time = close_time;
atomic_set(&next->budget,
- (next->interval * 1000) / q->picos_per_byte);
+ (next->interval * 1000) / atomic64_read(&q->picos_per_byte));
first_run:
rcu_assign_pointer(q->current_entry, next);
@@ -567,7 +576,8 @@ static void taprio_start_sched(struct Qdisc *sch, ktime_t start)
first->close_time = ktime_add_ns(start, first->interval);
atomic_set(&first->budget,
- (first->interval * 1000) / q->picos_per_byte);
+ (first->interval * 1000) /
+ atomic64_read(&q->picos_per_byte));
rcu_assign_pointer(q->current_entry, NULL);
spin_unlock_irqrestore(&q->current_entry_lock, flags);
@@ -575,6 +585,45 @@ static void taprio_start_sched(struct Qdisc *sch, ktime_t start)
hrtimer_start(&q->advance_timer, start, HRTIMER_MODE_ABS);
}
+static void taprio_set_picos_per_byte(struct net_device *dev,
+ struct taprio_sched *q)
+{
+ struct ethtool_link_ksettings ecmd;
+ int picos_per_byte = -1;
+
+ if (!__ethtool_get_link_ksettings(dev, &ecmd) &&
+ ecmd.base.speed != SPEED_UNKNOWN)
+ picos_per_byte = div64_s64(NSEC_PER_SEC * 1000LL * 8,
+ ecmd.base.speed * 1000 * 1000);
+
+ atomic64_set(&q->picos_per_byte, picos_per_byte);
+ pr_info("taprio: set %s's picos_per_byte to: %llu, linkspeed: %d\n",
+ dev->name, atomic64_read(&q->picos_per_byte), ecmd.base.speed);
+}
+
+static int taprio_dev_notifier(struct notifier_block *nb, unsigned long event,
+ void *ptr)
+{
+ struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+ struct taprio_sched *q;
+ struct net_device *qdev;
+
+ ASSERT_RTNL();
+
+ if (event != NETDEV_UP && event != NETDEV_CHANGE)
+ return NOTIFY_DONE;
+
+ spin_lock(&taprio_list_lock);
+ list_for_each_entry(q, &taprio_list, taprio_list) {
+ qdev = qdisc_dev(q->root);
+ if (qdev == dev)
+ taprio_set_picos_per_byte(dev, q);
+ }
+ spin_unlock(&taprio_list_lock);
+
+ return NOTIFY_DONE;
+}
+
static int taprio_change(struct Qdisc *sch, struct nlattr *opt,
struct netlink_ext_ack *extack)
{
@@ -582,9 +631,7 @@ static int taprio_change(struct Qdisc *sch, struct nlattr *opt,
struct taprio_sched *q = qdisc_priv(sch);
struct net_device *dev = qdisc_dev(sch);
struct tc_mqprio_qopt *mqprio = NULL;
- struct ethtool_link_ksettings ecmd;
int i, err, size;
- s64 link_speed;
ktime_t start;
err = nla_parse_nested(tb, TCA_TAPRIO_ATTR_MAX, opt,
@@ -657,14 +704,7 @@ static int taprio_change(struct Qdisc *sch, struct nlattr *opt,
mqprio->prio_tc_map[i]);
}
- if (!__ethtool_get_link_ksettings(dev, &ecmd))
- link_speed = ecmd.base.speed;
- else
- link_speed = SPEED_1000;
-
- q->picos_per_byte = div64_s64(NSEC_PER_SEC * 1000LL * 8,
- link_speed * 1000 * 1000);
-
+ taprio_set_picos_per_byte(dev, q);
start = taprio_get_start_time(sch);
if (!start)
return 0;
@@ -681,6 +721,10 @@ static void taprio_destroy(struct Qdisc *sch)
struct sched_entry *entry, *n;
unsigned int i;
+ spin_lock(&taprio_list_lock);
+ list_del(&q->taprio_list);
+ spin_unlock(&taprio_list_lock);
+
hrtimer_cancel(&q->advance_timer);
if (q->qdiscs) {
@@ -735,6 +779,10 @@ static int taprio_init(struct Qdisc *sch, struct nlattr *opt,
if (!opt)
return -EINVAL;
+ spin_lock(&taprio_list_lock);
+ list_add(&q->taprio_list, &taprio_list);
+ spin_unlock(&taprio_list_lock);
+
return taprio_change(sch, opt, extack);
}
@@ -947,14 +995,24 @@ static struct Qdisc_ops taprio_qdisc_ops __read_mostly = {
.owner = THIS_MODULE,
};
+static struct notifier_block taprio_device_notifier = {
+ .notifier_call = taprio_dev_notifier,
+};
+
static int __init taprio_module_init(void)
{
+ int err = register_netdevice_notifier(&taprio_device_notifier);
+
+ if (err)
+ return err;
+
return register_qdisc(&taprio_qdisc_ops);
}
static void __exit taprio_module_exit(void)
{
unregister_qdisc(&taprio_qdisc_ops);
+ unregister_netdevice_notifier(&taprio_device_notifier);
}
module_init(taprio_module_init);
--
2.21.0
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH net 2/2] net/sched: cbs: fix port_rate miscalculation
2019-03-13 22:43 [PATCH net 0/2] net/sched: taprio: cbs: Fix using invalid link speed Leandro Dorileo
2019-03-13 22:43 ` [PATCH net 1/2] net/sched: taprio: fix picos_per_byte miscalculation Leandro Dorileo
@ 2019-03-13 22:43 ` Leandro Dorileo
2019-03-14 16:12 ` kbuild test robot
1 sibling, 1 reply; 6+ messages in thread
From: Leandro Dorileo @ 2019-03-13 22:43 UTC (permalink / raw)
To: netdev
Cc: Jamal Hadi Salim, Cong Wang, Jiri Pirko, David S . Miller,
Vinicius Costa Gomes
The Credit Based Shaper heavily depends on link speed to calculate
the scheduling credits, we can't properly calculate the credits if the
device has failed to report the link speed.
In that case we can't dequeue packets assuming a wrong port rate that will
result into an inconsistent credit distribution.
This patch makes sure we fail to dequeue case:
1) __ethtool_get_link_ksettings() reports error or 2) the ethernet driver
failed to set the ksettings' speed value (setting link speed to
SPEED_UNKNOWN).
Additionally we properly re calculate the port rate whenever the link speed
is changed.
Fixes: 3d0bd028ffb4a ("net/sched: Add support for HW offloading for CBS")
Signed-off-by: Leandro Dorileo <leandro.maciel.dorileo@intel.com>
---
net/sched/sch_cbs.c | 91 ++++++++++++++++++++++++++++++++++++++-------
1 file changed, 77 insertions(+), 14 deletions(-)
diff --git a/net/sched/sch_cbs.c b/net/sched/sch_cbs.c
index c6a502933fe7..70f44244c08b 100644
--- a/net/sched/sch_cbs.c
+++ b/net/sched/sch_cbs.c
@@ -61,16 +61,20 @@
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/skbuff.h>
+#include <net/netevent.h>
#include <net/netlink.h>
#include <net/sch_generic.h>
#include <net/pkt_sched.h>
+static LIST_HEAD(cbs_list);
+static DEFINE_SPINLOCK(cbs_list_lock);
+
#define BYTES_PER_KBIT (1000LL / 8)
struct cbs_sched_data {
bool offload;
int queue;
- s64 port_rate; /* in bytes/s */
+ atomic64_t port_rate; /* in bytes/s */
s64 last; /* timestamp in ns */
s64 credits; /* in bytes */
s32 locredit; /* in bytes */
@@ -82,6 +86,7 @@ struct cbs_sched_data {
struct sk_buff **to_free);
struct sk_buff *(*dequeue)(struct Qdisc *sch);
struct Qdisc *qdisc;
+ struct list_head cbs_list;
};
static int cbs_child_enqueue(struct sk_buff *skb, struct Qdisc *sch,
@@ -181,6 +186,11 @@ static struct sk_buff *cbs_dequeue_soft(struct Qdisc *sch)
s64 credits;
int len;
+ if (atomic64_read(&q->port_rate) == -1) {
+ WARN_ONCE(1, "cbs: dequeue() called with unknown port rate.");
+ return NULL;
+ }
+
if (q->credits < 0) {
credits = timediff_to_credits(now - q->last, q->idleslope);
@@ -207,7 +217,8 @@ static struct sk_buff *cbs_dequeue_soft(struct Qdisc *sch)
/* As sendslope is a negative number, this will decrease the
* amount of q->credits.
*/
- credits = credits_from_len(len, q->sendslope, q->port_rate);
+ credits = credits_from_len(len, q->sendslope,
+ atomic64_read(&q->port_rate));
credits += q->credits;
q->credits = max_t(s64, credits, q->locredit);
@@ -294,6 +305,43 @@ static int cbs_enable_offload(struct net_device *dev, struct cbs_sched_data *q,
return 0;
}
+static void cbs_set_port_rate(struct net_device *dev, struct cbs_sched_data *q)
+{
+ struct ethtool_link_ksettings ecmd;
+ int port_rate = -1;
+
+ if (!__ethtool_get_link_ksettings(dev, &ecmd) &&
+ ecmd.base.speed != SPEED_UNKNOWN)
+ port_rate = ecmd.base.speed * 1000 * BYTES_PER_KBIT;
+
+ atomic64_set(&q->port_rate, port_rate);
+ pr_info("cbs: set %s's port_rate to: %llu, linkspeed: %d\n",
+ dev->name, atomic64_read(&q->port_rate), ecmd.base.speed);
+}
+
+static int cbs_dev_notifier(struct notifier_block *nb, unsigned long event,
+ void *ptr)
+{
+ struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+ struct cbs_sched_data *q;
+ struct net_device *qdev;
+
+ ASSERT_RTNL();
+
+ if (event != NETDEV_UP && event != NETDEV_CHANGE)
+ return NOTIFY_DONE;
+
+ spin_lock(&cbs_list_lock);
+ list_for_each_entry(q, &cbs_list, cbs_list) {
+ qdev = qdisc_dev(q->qdisc);
+ if (qdev == dev)
+ cbs_set_port_rate(dev, q);
+ }
+ spin_unlock(&cbs_list_lock);
+
+ return NOTIFY_DONE;
+}
+
static int cbs_change(struct Qdisc *sch, struct nlattr *opt,
struct netlink_ext_ack *extack)
{
@@ -315,16 +363,7 @@ static int cbs_change(struct Qdisc *sch, struct nlattr *opt,
qopt = nla_data(tb[TCA_CBS_PARMS]);
if (!qopt->offload) {
- struct ethtool_link_ksettings ecmd;
- s64 link_speed;
-
- if (!__ethtool_get_link_ksettings(dev, &ecmd))
- link_speed = ecmd.base.speed;
- else
- link_speed = SPEED_1000;
-
- q->port_rate = link_speed * 1000 * BYTES_PER_KBIT;
-
+ cbs_set_port_rate(dev, q);
cbs_disable_offload(dev, q);
} else {
err = cbs_enable_offload(dev, q, qopt, extack);
@@ -347,6 +386,7 @@ static int cbs_init(struct Qdisc *sch, struct nlattr *opt,
{
struct cbs_sched_data *q = qdisc_priv(sch);
struct net_device *dev = qdisc_dev(sch);
+ int err;
if (!opt) {
NL_SET_ERR_MSG(extack, "Missing CBS qdisc options which are mandatory");
@@ -367,7 +407,17 @@ static int cbs_init(struct Qdisc *sch, struct nlattr *opt,
qdisc_watchdog_init(&q->watchdog, sch);
- return cbs_change(sch, opt, extack);
+ err = cbs_change(sch, opt, extack);
+ if (err)
+ return err;
+
+ if (!q->offload) {
+ spin_lock(&cbs_list_lock);
+ list_add(&q->cbs_list, &cbs_list);
+ spin_unlock(&cbs_list_lock);
+ }
+
+ return 0;
}
static void cbs_destroy(struct Qdisc *sch)
@@ -375,8 +425,11 @@ static void cbs_destroy(struct Qdisc *sch)
struct cbs_sched_data *q = qdisc_priv(sch);
struct net_device *dev = qdisc_dev(sch);
- qdisc_watchdog_cancel(&q->watchdog);
+ spin_lock(&cbs_list_lock);
+ list_del(&q->cbs_list);
+ spin_unlock(&cbs_list_lock);
+ qdisc_watchdog_cancel(&q->watchdog);
cbs_disable_offload(dev, q);
if (q->qdisc)
@@ -487,14 +540,24 @@ static struct Qdisc_ops cbs_qdisc_ops __read_mostly = {
.owner = THIS_MODULE,
};
+static struct notifier_block cbs_device_notifier = {
+ .notifier_call = cbs_dev_notifier,
+};
+
static int __init cbs_module_init(void)
{
+ int err = register_netdevice_notifier(&cbs_device_notifier);
+
+ if (err)
+ return err;
+
return register_qdisc(&cbs_qdisc_ops);
}
static void __exit cbs_module_exit(void)
{
unregister_qdisc(&cbs_qdisc_ops);
+ unregister_netdevice_notifier(&cbs_device_notifier);
}
module_init(cbs_module_init)
module_exit(cbs_module_exit)
--
2.21.0
^ permalink raw reply related [flat|nested] 6+ messages in thread