Re: [PATCH 02/16] hyper-v: trace vmbus_on_message()

Vitaly Kuznetsov
2017-09-21T08:17:21Z

Steven Rostedt <rostedt@goodmis.org> writes:

> On Wed, 20 Sep 2017 19:21:53 +0200
> Vitaly Kuznetsov <vkuznets@redhat.com> wrote:
>
>> diff --git a/drivers/hv/hv_trace.h b/drivers/hv/hv_trace.h
>> index 9a29ef55477d..72911dfc9682 100644
>> --- a/drivers/hv/hv_trace.h
>> +++ b/drivers/hv/hv_trace.h
>> @@ -14,6 +14,14 @@ TRACE_EVENT(vmbus_on_msg_dpc,
>> TP_printk("message %u received", __entry->msgtype)
>> );
>>
>> +TRACE_EVENT(vmbus_on_message,
>> + TP_PROTO(const struct vmbus_channel_message_header *hdr),
>> + TP_ARGS(hdr),
>> + TP_STRUCT__entry(__field(unsigned int, msgtype)),
>> + TP_fast_assign(__entry->msgtype = hdr->msgtype),
>> + TP_printk("processing message %u", __entry->msgtype)
>> + );
>
> Whenever you have two trace events with everything the same but the
> TP_printk(), you can save a little space by using DEFINE_EVENT_PRINT()
>
> DECLARE_EVENT_CLASS(vmbus_hdr_msg,
> TP_PROTO(const struct vmbus_channel_message_header *hdr),
> TP_ARGS(hdr),
> TP_STRUCT__entry(__field(unsigned int, msgtype),
> TP_fast_assign(__entry->msg = hdr->msgtype;),
> TP_printk("msgtype=%d", __entry->msgtype)
> );
>
> DEFINE_EVENT_PRINT(vmbus_hdr_msg, vmbus_on_msg_dpc,
> TP_PROTO(const struct vmbus_channel_message_header *hdr),
> TP_ARGS(hdr),
> TP_printk("message %u received", __entry->msgtype));
>
> DEFINE_EVENT_PRINT(vmbus_hdr_msg, vmbus_on_message,
> TP_PROTO(const struct vmbus_channel_message_header *hdr),
> TP_ARGS(hdr),
> TP_printk("processing message %u", __entry->msgtype));
>
> This will use the same functions required to save and record the
> message but will use a different function to output it to the trace.

Oh, thanks! This seems to be useful for
vmbus_on_msg_dpc/vmbus_on_message only as all the rest needs to parse
different structures. Will use it in v2.

--
Vitaly