Re: [PATCH 10/17] hyper-v: trace vmbus_open()

[Vitaly Kuznetsov]

Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> writes:

> On Sun, Oct 29, 2017 at 12:21:09PM -0700, kys@xxxxxxxxxxxxxxxxxxxxxx wrote:
>> From: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
>> 
>> Add tracepoint to CHANNELMSG_OPENCHANNEL sender.
>> 
>> Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
>> Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
>> ---
>>  drivers/hv/channel.c  |  2 ++
>>  drivers/hv/hv_trace.h | 27 +++++++++++++++++++++++++++
>>  2 files changed, 29 insertions(+)
>> 
>> diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
>> index a406beb10dd0..739b3fe1e0fb 100644
>> --- a/drivers/hv/channel.c
>> +++ b/drivers/hv/channel.c
>> @@ -185,6 +185,8 @@ int vmbus_open(struct vmbus_channel *newchannel, u32 send_ringbuffer_size,
>>  	ret = vmbus_post_msg(open_msg,
>>  			     sizeof(struct vmbus_channel_open_channel), true);
>>  
>> +	trace_vmbus_open(open_msg, ret);
>
> Why add tracepoints for things that ftrace can handle automatically?

This series adds pretty prints for structures printing what is needed
and in the right format significantly simplifying debugging. And it
wouldn't make sense to add tracepoints to *some* messages-related
functions and skip others where parsing is more trivial.

-- 
  Vitaly