Messages in this thread | | | Date | Tue, 15 Oct 2013 18:23:41 +0900 | From | Masami Hiramatsu <> | Subject | Re: [PATCH v10 04/12] tracing: Add 'snapshot' event trigger command |
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(2013/10/11 23:04), Tom Zanussi wrote: > 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.
Hmm, it seems that Steven added these EXPORT_SYMBOL_GPL at commit 1b22e382. Steven, would you have any idea to call these functions from outside of the ftrace?
Thank you,
-- Masami HIRAMATSU IT Management Research Dept. Linux Technology Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: masami.hiramatsu.pt@hitachi.com
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