Messages in this thread | | | Subject | Re: [PATCH v10 04/12] tracing: Add 'snapshot' event trigger command | From | Tom Zanussi <> | Date | Fri, 11 Oct 2013 09:04:28 -0500 |
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On Fri, 2013-10-11 at 22:47 +0900, Masami Hiramatsu wrote: > (2013/10/11 9:48), Tom Zanussi wrote: > > /** > > + * tracing_alloc_snapshot - allocate snapshot buffer. > > + * > > + * This only allocates the snapshot buffer if it isn't already > > + * allocated - it doesn't also take a snapshot. > > + * > > + * This is meant to be used in cases where the snapshot buffer needs > > + * to be set up for events that can't sleep but need to be able to > > + * trigger a snapshot. > > + */ > > +int tracing_alloc_snapshot(void) > > +{ > > + struct trace_array *tr = &global_trace; > > + int ret; > > + > > + ret = alloc_snapshot(tr); > > + WARN_ON(ret < 0); > > + > > + return ret; > > +} > > +EXPORT_SYMBOL_GPL(tracing_alloc_snapshot); > > Out of curiously, why this symbol is exported to modules? > The functions which are called directly from trace_event macros > should be exported because those macros can be used in module code, > but I couldn't find this in such code, at a glance. >
tracing_alloc_snapshot() goes along with tracing_snapshot() and tracing_snapshot_alloc() which are already exported - you should be able to take a snapshot from a module, or do a combined snapshot/alloc or (now) just the alloc.
Tom
> Thank you, > > >
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