Re: [PATCH v2 1/2] tracing: Move tracepoint callbacks into DEFINE

[Frederic Weisbecker <fweisbec@gmail.com>]

On Fri, Aug 21, 2009 at 12:34:28PM -0700, Josh Stone wrote:
> On 08/21/2009 10:52 AM, Jason Baron wrote:
> > this means that when CONFIG_EVENT_TRACING is set, the 'generic' syscall
> > enter/exit will show up as events in the debugfs, but enabling them
> > wouldn't do anything. I think we should simply drop the
> > 'CONFIG_FTRACE_SYSCALLS' 'ifdef' and 'else' clause. That will give us
> > what we want - tying these callbacks directly to tracepoint.
> 
> But only x86 and s390 have TIF_SYSCALL_FTRACE, while kernel/tracepoint.c
> must still compile everywhere that has CONFIG_TRACEPOINTS=y.
> 
> Maybe it would be better to make that #ifdef TIF_SYSCALL_FTRACE, and
> then also #ifdef the TRACE_EVENT declaration, so it will only show up on
> kernels that actually support it.


Instead of testing TIF_SYSCALL_FTRACE, I'd suggest testing HAVE_FTRACE_SYSCALLS.
This makes more sense and is more verbose wrt its role in the conditionnal definition,
given its macro name.

 
> Also, since this event is now usable outside of ftrace, would you object
> to renaming the flag TIF_SYSCALL_TRACEPOINT?
> 
> Josh