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From: Ingo M. <mi...@el...> - 2009-11-03 07:33:07
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* Masami Hiramatsu <mhi...@re...> wrote: > Masami Hiramatsu wrote: >> Masami Hiramatsu wrote: >>> Ingo Molnar wrote: >>>> What we want here is two fold: >>>> >>>> - enable kprobes event support when perf events is enabled and kprobes >>>> is enabled. We dont want another config option for it. >>> >>> Sure, at least that combination should enable kprobe-tracer forcibly. >> >> Hmm, someone may not want to enables kprobe-tracer. Perhaps, >> "default y if (EVENT_PROFILE)" is enough, isn't it? > > Oops, this causes recursive dependency error :-( > > kernel/trace/Kconfig:90:error: found recursive dependency: TRACING -> > EVENT_TRACING -> EVENT_PROFILE -> KPROBE_TRACER -> GENERIC_TRACER -> TRACING This dependency problem can be resolved by simply making it 'default y' - the option itself depends on KPROBES already, which is default-off - so no need to also make it depend on EVENT_PROFILE. btw., it would be nice to re-name it to 'KPROBE_EVENTS'. If the probe point is used as a count - like in the __switch_to example i cited - there's no tracing going on at all. Ingo |