Messages in this thread | | | Subject | Re: Q: perf_install_in_context/perf_event_enable are racy? | From | Peter Zijlstra <> | Date | Thu, 27 Jan 2011 18:11:34 +0100 |
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On Thu, 2011-01-27 at 17:57 +0100, Oleg Nesterov wrote: > > > With, however, things are more interesting. 2 seems to be adequately > > covered by the patch I just send, the IPI will bail and the next > > sched-in of the relevant task will pick matters up. 1 otoh doesn't seem > > covered, the IPI will bail, leaving us stranded. > > Hmm, yes... Strangely, I missed that when I was thinking about in_ctxsw. > > Perhaps, we can change task_oncpu_function_call() so that it returns > -EAGAIN in case it hits in_ctxsw != 0? If the caller sees -EAGAIN, it > should always retry even if !ctx->is_active.
That would be very easy to do, we can pass a return value through the task_function_call structure.
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