Re: [PATCH 0/8] [GIT PULL] TRACE_EVENT for modules

[Jeremy Fitzhardinge]

Steven Rostedt wrote:
> On Tue, 14 Apr 2009, Jeremy Fitzhardinge wrote:
>
>   
> > Theodore Tso wrote:
> >     
> > > Any chance you could support something like this?
> > >
> > >   
> > >       
> > I think that's already there.  I'm defining
> > arch/x86/include/asm/paravirt-trace.h with:
> >
> > #ifndef _ASM_X86_PARAVIRT_TRACE_H
> > #define _ASM_X86_PARAVIRT_TRACE_H
> >
> > #include <linux/tracepoint.h>
> > #include <asm/paravirt_types.h>
> >
> > #undef TRACE_SYSTEM
> > #define TRACE_SYSTEM pvops
> >
> > #define TRACE_INCLUDE_FILE	paravirt-trace
> > #define TRACE_INCLUDE_PATH	asm
> > [...]
> >
> >
> > Which ends up including <asm/paravirt-trace.h>
> >     
>
> Not quite. It ends up looking like
>
> #include "asm/paravirt-trace.h"
>
> As long as there is no "asm" directory in the include/trace directory, I 
> think that is fine.

OK.

I'm having a bit of trouble with paravirt-trace.h when I actually 
include it in paravirt.h.  asm/paravirt.h is itself included in lots of 
places, and so its fairly easy to end up with cyclic include 
dependencies which are fairly painful.  In this case I'm seeing 
asm/paravirt.h -> linux/tracepoint.h -> linux/rcupate.h -> {lots of 
stuff}, which gives errors like:

 CC      arch/x86/kernel/asm-offsets.s
In file included from /home/jeremy/git/linux/include/linux/thread_info.h:55,
                from /home/jeremy/git/linux/include/linux/preempt.h:9,
                from /home/jeremy/git/linux/include/linux/spinlock.h:50,
                from /home/jeremy/git/linux/include/linux/rcupdate.h:37,
                from /home/jeremy/git/linux/include/linux/tracepoint.h:18,
                from /home/jeremy/git/linux/arch/x86/include/asm/paravirt-trace.h:4,
                from /home/jeremy/git/linux/arch/x86/include/asm/paravirt.h:18,
                from /home/jeremy/git/linux/arch/x86/include/asm/irqflags.h:55,
                from /home/jeremy/git/linux/include/linux/irqflags.h:57,
                from /home/jeremy/git/linux/arch/x86/include/asm/system.h:11,
                from /home/jeremy/git/linux/arch/x86/include/asm/processor.h:17,
                from /home/jeremy/git/linux/include/linux/prefetch.h:14,
                from /home/jeremy/git/linux/include/linux/list.h:6,
                from /home/jeremy/git/linux/include/linux/module.h:9,
                from /home/jeremy/git/linux/include/linux/crypto.h:21,
                from /home/jeremy/git/linux/arch/x86/kernel/asm-offsets_64.c:7,
                from /home/jeremy/git/linux/arch/x86/kernel/asm-offsets.c:4:
/home/jeremy/git/linux/arch/x86/include/asm/thread_info.h:34: error: expected specifier-qualifier-list before 'mm_segment_t'



I'm wondering if there's much downside in making the code __DO_TRACE() 
out of line so that we can make tracepoint.h have absolutely minimal 
include dependencies?

   J
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