Messages in this thread |  | | | Date | Thu, 11 Aug 2011 14:49:10 +0900 | | From | Masami Hiramatsu <> | | Subject | Re: [RFC PATCH][3.0] Tracepoint: dissociate from module mutex (v2) |
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(2011/08/11 12:23), Steven Rostedt wrote: > On Thu, 2011-08-11 at 12:14 +0900, Masami Hiramatsu wrote: >> (2011/08/11 4:18), Mathieu Desnoyers wrote: >>> Copy the information needed from struct module into a local module list >>> held within tracepoint.c from within the module coming/going notifier. >>> >>> This vastly simplifies locking of tracepoint registration / >>> unregistration, because we don't have to take the module mutex to >>> register and unregister tracepoints anymore. Steven Rostedt ran into >>> dependency problems related to modules mutex vs kprobes mutex vs ftrace >>> mutex vs tracepoint mutex that seems to be hard to fix without removing >>> this dependency between tracepoint and module mutex. (note: it should be >>> investigated whether kprobes could benefit of being dissociated from the >>> modules mutex too.) >> >> Thanks, it seems that kprobes has already mostly done that. >> It holds module_mutex only in kprobe_optimizer. However, >> it seems meaningless, because kprobe_mutex already protects >> kprobe_optimizer against the kprobes module notifier. >> Thus, a module removing will stays on the notifier until >> the optimizer runs out. So I think we can remove that mutex lock. >> > > So should I change my patch 4/5 to just remove the module_mutex? > > [PATCH 4/5][RFC] kprobes: Inverse taking of module_mutex with kprobe_mutex
Right, it should be changed. :-)
Thank you,
-- Masami HIRAMATSU Software Platform Research Dept. Linux Technology Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: masami.hiramatsu.pt@hitachi.com
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