Re: [PATCH] export softirq_to_name symbol

[Frederic Weisbecker <fweisbec@gmail.com>]

On Fri, May 01, 2009 at 04:10:28PM -0400, Christoph Hellwig wrote:
> On Fri, May 01, 2009 at 01:07:34PM -0700, Josh Stone wrote:
> > I'm adding SystemTap support for the format strings in the TRACE_EVENT
> > macros.  The softirq's TP_fast_assign uses softirq_to_name, and so that
> > array is needed to prepare the softirq's trace string.
> > 
> > So, there's no explicit reference to the symbol in SystemTap -- it's
> > just indirectly referenced by the tracepoint declaration.
> 
> TP_fast_assign should only be called by core code, it's the piece that
> copies the trace into the ring buffer.  If systemtap copies events into
> the ring buffer from modular code something is deeply wrong in it's
> design.


In itself, the use of TRACE_EVENT from a module is fine, otherwise
Steve wouldn't have written the module support.

For example the mac80211 subsystem can be built as a module, and
if a tracing code is merged for this subsystem, we want it to be
usable whenever it is build as a module or not.

Frederic.