Subject: Re: [PATCH -next] trace_skb: fix build when CONFIG_NET is not enabled

From: Ingo Molnar <[email-masked]>
Date: Tue, 18 Aug 2009 01:00:32 +0200

* Ingo Molnar <[email-masked]> wrote:

> 
> * David Miller <[email-masked]> wrote:
> 
> > From: Ingo Molnar <[email-masked]>
> > Date: Mon, 17 Aug 2009 23:58:08 +0200
> > 
> > >> --- linux-next-20090817.orig/kernel/trace/Kconfig
> > >> +++ linux-next-20090817/kernel/trace/Kconfig
> > >> @@ -236,6 +236,7 @@ config BOOT_TRACER
> > >>  
> > >>  config SKB_SOURCES_TRACER
> > >>  	bool "Trace skb source information"
> > >> +	depends on NET
> > >>  	select GENERIC_TRACER
> > >>  	help
> > >>  	   This tracer helps developers/sysadmins correlate skb allocation and
> > > 
> > > Hm, there's nothing like this in the tracing tree.
> > > 
> > > Could we please move kernel/trace/* commits to the tracing tree, so 
> > > that it gets adequate testing and review, etc?
> > 
> > This one (like previous networking tracing changes Neil has made) 
> > touched a decent amount of networking code, and thus we 
> > integrated it into net-next-2.6
> 
> the three skb-sources-tracer patches i saw submitted were:
> 
>  include/trace/events/skb.h |   20 ++++++++++++++++++++
>  net/core/datagram.c        |    3 +++
>  2 files changed, 23 insertions(+)
> 
>  kernel/traceKconfig |   10 ++++++++++
> 
>  kernel/trace/Makefile            |    1
>  kernel/trace/trace.h             |   19 ++++++
>  kernel/trace/trace_skb_sources.c |  154 ++++++++++++++++++++++++++++++++++++++++++++++++++++
> 
> only touched the networking code for 3 lines in 
> net/core/datagram.c.
> 
> Think about it: how would you react if i added a new file to 
> net/core/ and modified net/Kconfig, and then broke the build? 
> You'd quite likely insist on it being done via net-next-2.6, 
> right? You'd also likely be upset about that kind of change, 
> wouldnt you?
> 
> Also, has the review feedback from the tracing folks been 
> addressed? Please separate these patches out and lets do this 
> properly, this approach is not acceptable.

btw., this isnt just a question of patch logistics - these patches 
look unreviewed to me. Why is a new ftrace plugin needed? Why arent 
they defined in a TRACE_EVENT() form? That way they'd be generally 
usable together with other tracepoints, and would likely be enabled 
in most distros. That way they could also be added via other trees, 
as TRACE_EVENT() is a generic facility.

We try to migrate ftrace plugins to TRACE_EVENT() tracepoints.

	Ingo