Messages in this thread | | | Date | Mon, 14 Sep 2009 20:55:41 +0200 | From | Frederic Weisbecker <> | Subject | Re: [PATCH tracing/kprobes 4/7] tracing/kprobes: Add event profiling support |
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On Mon, Sep 14, 2009 at 12:54:24PM -0400, Masami Hiramatsu wrote: >>> I'd like to have a dispatcher function and flags internally :) >> >> >> You mean kprobes that could support multiple probes? >> That would be a nice solution IMHO... > > Yeah, actually kprobes could support multiple probes on the > same point. But kprobe structure has many extensions which > kprobe-tracer doesn't need, e.g. post_handler/break_handler, > opcode, arch sprcific instructions. > Kretprobe consumes more memories for storing return points :(. > > Thus, if we know there are two functions to be called on the > same probe point, I think it is better to have a dispatcher. > (Especially, in this case, we can call fixed functions, so > it's easier way.) >
Yeah, you could union the post_handler with profile_handler or something like that.
It depends if kprobes may need one day to support an undeterminate number of probes.
Also, is the post_handler called at the same location than the normal probe? And is a post handler called even if there is no normal handler?
There might be some of such factors that would force you to handle a lot of corner cases, things that you wouldn't need to worry about if you just had to maintain a simple rcu list of probes to call.
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