| Message ID | 20210711050007.1200-2-xiangxia.m.yue@gmail.com (mailing list archive) |
|---|---|
| State | Deferred |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net-next,1/2] qdisc: add tracepoint qdisc:qdisc_enqueue for enqueued SKBs | expand |
| Context | Check | Description |
|---|---|---|
| netdev/apply | fail | Patch does not apply to net-next |
| netdev/tree_selection | success | Clearly marked for net-next |
On Sat, Jul 10, 2021 at 10:00 PM <xiangxia.m.yue@gmail.com> wrote: > > From: Tonghao Zhang <xiangxia.m.yue@gmail.com> > > The main purpose of this tracepoint is to monitor what, > how many and why packets were requeued. The txq_state can > be used for determining the reason for packets requeued. Hmm, how can I figure out the requeue is caused by validate_xmit_skb_list() when it returns again==true? I fail to see you trace it. For the other case, we can figure it out by trace_net_dev_xmit(). So, in short, your patch looks useless. Thanks.
On Mon, Jul 12, 2021 at 11:51 AM Cong Wang <xiyou.wangcong@gmail.com> wrote: > > On Sat, Jul 10, 2021 at 10:00 PM <xiangxia.m.yue@gmail.com> wrote: > > > > From: Tonghao Zhang <xiangxia.m.yue@gmail.com> > > > > The main purpose of this tracepoint is to monitor what, > > how many and why packets were requeued. The txq_state can > > be used for determining the reason for packets requeued. > > Hmm, how can I figure out the requeue is caused by > validate_xmit_skb_list() when it returns again==true? > I fail to see you trace it. This patch looks not good. > For the other case, we can figure it out by trace_net_dev_xmit(). > So, in short, your patch looks useless. > > Thanks. -- Best regards, Tonghao
On Mon, Jul 12, 2021 at 12:17 PM Tonghao Zhang <xiangxia.m.yue@gmail.com> wrote: > > On Mon, Jul 12, 2021 at 11:51 AM Cong Wang <xiyou.wangcong@gmail.com> wrote: > > > > On Sat, Jul 10, 2021 at 10:00 PM <xiangxia.m.yue@gmail.com> wrote: > > > > > > From: Tonghao Zhang <xiangxia.m.yue@gmail.com> > > > > > > The main purpose of this tracepoint is to monitor what, > > > how many and why packets were requeued. The txq_state can > > > be used for determining the reason for packets requeued. > > > > Hmm, how can I figure out the requeue is caused by > > validate_xmit_skb_list() when it returns again==true? Hi cong Consider this patch again. The main purpose of this tracepoint is to monitor what, how many and why packets were requeued. So should we figure out packets required by validate_xmit_skb_list or dev_hard_start_xmit ? because we may want to know what packets were requeued and how many. if we should figure out, we can add more arg for trace, right ? > > I fail to see you trace it. > This patch looks not good. > > For the other case, we can figure it out by trace_net_dev_xmit(). > > So, in short, your patch looks useless. > > > > Thanks. > > > > -- > Best regards, Tonghao -- Best regards, Tonghao
On Mon, Jul 12, 2021 at 7:07 PM Tonghao Zhang <xiangxia.m.yue@gmail.com> wrote: > > On Mon, Jul 12, 2021 at 12:17 PM Tonghao Zhang <xiangxia.m.yue@gmail.com> wrote: > > > > On Mon, Jul 12, 2021 at 11:51 AM Cong Wang <xiyou.wangcong@gmail.com> wrote: > > > > > > On Sat, Jul 10, 2021 at 10:00 PM <xiangxia.m.yue@gmail.com> wrote: > > > > > > > > From: Tonghao Zhang <xiangxia.m.yue@gmail.com> > > > > > > > > The main purpose of this tracepoint is to monitor what, > > > > how many and why packets were requeued. The txq_state can > > > > be used for determining the reason for packets requeued. > > > > > > Hmm, how can I figure out the requeue is caused by > > > validate_xmit_skb_list() when it returns again==true? > Hi cong > Consider this patch again. > The main purpose of this tracepoint is to monitor what, how many and > why packets were requeued. > So should we figure out packets required by validate_xmit_skb_list or > dev_hard_start_xmit ? > because we may want to know what packets were requeued and how many. > > if we should figure out, we can add more arg for trace, right ? Figuring out which case is important to determine the cause, so you have to fix it to make it useful. Thanks.
diff --git a/include/trace/events/qdisc.h b/include/trace/events/qdisc.h index b0e76237bb74..c6187a8fc103 100644 --- a/include/trace/events/qdisc.h +++ b/include/trace/events/qdisc.h @@ -78,6 +78,38 @@ TRACE_EVENT(qdisc_dequeue, __entry->txq_state, __entry->packets, __entry->skbaddr ) ); +TRACE_EVENT(qdisc_requeue, + + TP_PROTO(struct sk_buff *skb, struct Qdisc *qdisc, + const struct netdev_queue *txq), + + TP_ARGS(skb, qdisc, txq), + + TP_STRUCT__entry( + __field( struct Qdisc *, qdisc ) + __field(const struct netdev_queue *, txq ) + __field( void *, skbaddr ) + __field( int, ifindex ) + __field( u32, handle ) + __field( u32, parent ) + __field( unsigned long, txq_state) + ), + + TP_fast_assign( + __entry->qdisc = qdisc; + __entry->txq = txq; + __entry->skbaddr = skb; + __entry->ifindex = txq->dev ? txq->dev->ifindex : 0; + __entry->handle = qdisc->handle; + __entry->parent = qdisc->parent; + __entry->txq_state = txq->state; + ), + + TP_printk("requeue ifindex=%d qdisc handle=0x%X parent=0x%X txq_state=0x%lX skbaddr=%p", + __entry->ifindex, __entry->handle, __entry->parent, + __entry->txq_state, __entry->skbaddr) +); + TRACE_EVENT(qdisc_reset, TP_PROTO(struct Qdisc *q), diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index 75605075178f..0701d1e9d221 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -137,7 +137,8 @@ static inline void qdisc_enqueue_skb_bad_txq(struct Qdisc *q, spin_unlock(lock); } -static inline void dev_requeue_skb(struct sk_buff *skb, struct Qdisc *q) +static inline void dev_requeue_skb(struct sk_buff *skb, struct Qdisc *q, + struct netdev_queue *txq) { spinlock_t *lock = NULL; @@ -149,6 +150,7 @@ static inline void dev_requeue_skb(struct sk_buff *skb, struct Qdisc *q) while (skb) { struct sk_buff *next = skb->next; + trace_qdisc_requeue(skb, q, txq); __skb_queue_tail(&q->gso_skb, skb); /* it's still part of the queue */ @@ -325,7 +327,7 @@ bool sch_direct_xmit(struct sk_buff *skb, struct Qdisc *q, if (root_lock) spin_lock(root_lock); - dev_requeue_skb(skb, q); + dev_requeue_skb(skb, q, txq); return false; } #endif @@ -353,7 +355,7 @@ bool sch_direct_xmit(struct sk_buff *skb, struct Qdisc *q, net_warn_ratelimited("BUG %s code %d qlen %d\n", dev->name, ret, q->q.qlen); - dev_requeue_skb(skb, q); + dev_requeue_skb(skb, q, txq); return false; }