Tracepoint trace_qdisc_enqueue() is introduced to trace skb at
the entrance of TC layer on TX side. This is similar to
trace_qdisc_dequeue():
1. For both we only trace successful cases. The failure cases
can be traced via trace_kfree_skb().
2. They are called at entrance or exit of TC layer, not for each
->enqueue() or ->dequeue(). This is intentional, because
we want to make trace_qdisc_enqueue() symmetric to
trace_qdisc_dequeue(), which is easier to use.
The return value of qdisc_enqueue() is not interesting here,
we have Qdisc's drop packets in ->dequeue(), it is impossible to
trace them even if we have the return value, the only way to trace
them is tracing kfree_skb().
We only add information we need to trace ring buffer. If any other
information is needed, it is easy to extend it without breaking ABI,
see commit
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| acpi | ||
| asm-generic | ||
| clocksource | ||
| crypto | ||
| drm | ||
| dt-bindings | ||
| keys | ||
| kunit | ||
| kvm | ||
| linux | ||
| math-emu | ||
| media | ||
| memory | ||
| misc | ||
| net | ||
| pcmcia | ||
| ras | ||
| rdma | ||
| scsi | ||
| soc | ||
| sound | ||
| target | ||
| trace | ||
| uapi | ||
| vdso | ||
| video | ||
| xen | ||