On Tue, 15 Aug 2017 20:31:44 -0600 David Ahern <dsah...@gmail.com> wrote:
> On 8/15/17 1:11 PM, Jesper Dangaard Brouer wrote: > > diff --git a/include/trace/events/qdisc.h b/include/trace/events/qdisc.h > > new file mode 100644 > > index 000000000000..60d0d8bd336d > > --- /dev/null > > +++ b/include/trace/events/qdisc.h > > @@ -0,0 +1,50 @@ > > +#undef TRACE_SYSTEM > > +#define TRACE_SYSTEM qdisc > > + > > +#if !defined(_TRACE_QDISC_H) || defined(TRACE_HEADER_MULTI_READ) > > +#define _TRACE_QDISC_H_ > > + > > +#include <linux/skbuff.h> > > +#include <linux/netdevice.h> > > +#include <linux/tracepoint.h> > > +#include <linux/ftrace.h> > > + > > +TRACE_EVENT(qdisc_dequeue, > > + > > + TP_PROTO(struct Qdisc *qdisc, const struct netdev_queue *txq, > > + int packets, struct sk_buff *skb), > > + > > + TP_ARGS(qdisc, txq, packets, skb), > > + > > + TP_STRUCT__entry( > > + __field( struct Qdisc *, qdisc ) > > + __field(const struct netdev_queue *, txq ) > > Why save qdisc and txq pointers in the tracepoint data? I wanted to attach a BPF program, and allow it to dereference these pointers. Which is done via bpf_probe_read like: unsigned int qdisc_flags; bpf_probe_read(&qdisc_flags, sizeof(qdisc_flags), &ctx->qdisc->flags); -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer
