linux-kernel - Re: [PATCH 02/16] hyper-v: trace vmbus_on

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Date:   Tue, 3 Oct 2017 09:54:47 -0700
From:   Stephen Hemminger <stephen@...workplumber.org>
To:     Vitaly Kuznetsov <vkuznets@...hat.com>
Cc:     Steven Rostedt <rostedt@...dmis.org>,
        Stephen Hemminger <sthemmin@...rosoft.com>,
        Haiyang Zhang <haiyangz@...rosoft.com>,
        linux-kernel@...r.kernel.org, devel@...uxdriverproject.org
Subject: Re: [PATCH 02/16] hyper-v: trace vmbus_on_message()

On Thu, 21 Sep 2017 10:17:18 +0200
Vitaly Kuznetsov <vkuznets@...hat.com> wrote:

> Steven Rostedt <rostedt@...dmis.org> writes:
> 
> > On Wed, 20 Sep 2017 19:21:53 +0200
> > Vitaly Kuznetsov <vkuznets@...hat.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.
> 

I just used this patch. Since function name is already in the trace message
no need to have different print's for each one.

From ff85967810c216eb01d181789af4f56bd00dc9b9 Mon Sep 17 00:00:00 2001
From: Stephen Hemminger <sthemmin@...rosoft.com>
Date: Tue, 3 Oct 2017 09:24:11 -0700
Subject: [PATCH 3/4] hyperv: fix warnings in trace print

This gets rid of the build warnings from unused printf format.
And uses common class for print.
---
 drivers/hv/hv_trace.h | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/hv/hv_trace.h b/drivers/hv/hv_trace.h
index be7762955650..4755c4640e39 100644
--- a/drivers/hv/hv_trace.h
+++ b/drivers/hv/hv_trace.h
@@ -11,18 +11,18 @@ DECLARE_EVENT_CLASS(vmbus_hdr_msg,
 	TP_ARGS(hdr),
 	TP_STRUCT__entry(__field(unsigned int, msgtype)),
 	TP_fast_assign(__entry->msgtype = hdr->msgtype;),
-	TP_printk("msgtype=%d", __entry->msgtype)
+	TP_printk("msgtype=%u", __entry->msgtype)
 );
 
-DEFINE_EVENT_PRINT(vmbus_hdr_msg, vmbus_on_msg_dpc,
+DEFINE_EVENT(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));
+	TP_ARGS(hdr)
+);
 
-DEFINE_EVENT_PRINT(vmbus_hdr_msg, vmbus_on_message,
+DEFINE_EVENT(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));
+        TP_ARGS(hdr)
+);
 
 TRACE_EVENT(vmbus_onoffer,
 	    TP_PROTO(const struct vmbus_channel_offer_channel *offer),
-- 
2.11.0