Re: [PATCH] prctl: Add PR_SET_TIMERSLACK_PID for setting timer slack of an arbitrary thread.

From	John Stultz <john.stultz@linaro.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH] prctl: Add PR_SET_TIMERSLACK_PID for setting timer slack of an arbitrary thread.
Date	2016-02-06 03:50 +0100
Message-ID	<qZ16G-LB-7@gated-at.bofh.it> (permalink)
References	(5 earlier) <qYVuh-5aD-3@gated-at.bofh.it> <qYVDY-5dV-5@gated-at.bofh.it> <qYXcJ-6kF-3@gated-at.bofh.it> <qYZoe-7TF-5@gated-at.bofh.it> <qZ0ki-ev-7@gated-at.bofh.it>
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On Fri, Feb 5, 2016 at 5:56 PM, Andrew Morton <akpm@linux-foundation.org> wrote:
> On Fri, 5 Feb 2016 16:51:02 -0800 John Stultz <john.stultz@linaro.org> wrote:
>> Alternatively, with the /proc/pid/timerslack_ns interface I'm working
>> on, we can make the backing storage a long long and support 64bits of
>> nanoseconds on all architectures. (But again, we can't really change
>> PR_SET/GET_TIMERSLACK, so 32bit systems might see strange values from
>> that with larger then uint slack values).
>>
>> Or I can just leave it as ULONG_MAX on all interfaces.
>>
>> Thoughts or preferences?
>
> /proc/<pid>/timer_slack_us?

So the issue isn't so much in the new interface (we can have it take a
long long), but really in the existing PR_GET/SET_TIMERSLACK. I'm just
trying to figure out if following the existing oddness is the best
approach, or if we should make the new interface do a more consistent
thing, but with the result that the PR_GET_TIMERSLACK interface might
return "incorrect" values (just the lower 32bits).

thanks
-john

Thread

[PATCH] prctl: Add PR_SET_TIMERSLACK_PID for setting timer slack of an arbitrary thread. John Stultz <john.stultz@linaro.org> - 2016-02-05 19:10 +0100
  Re: [PATCH] prctl: Add PR_SET_TIMERSLACK_PID for setting timer slack  of an arbitrary thread. Kees Cook <keescook@chromium.org> - 2016-02-05 21:20 +0100
    Re: [PATCH] prctl: Add PR_SET_TIMERSLACK_PID for setting timer slack  of an arbitrary thread. John Stultz <john.stultz@linaro.org> - 2016-02-05 21:20 +0100
  Re: [PATCH] prctl: Add PR_SET_TIMERSLACK_PID for setting timer  slack of an arbitrary thread. Andrew Morton <akpm@linux-foundation.org> - 2016-02-05 21:20 +0100
    Re: [PATCH] prctl: Add PR_SET_TIMERSLACK_PID for setting timer slack  of an arbitrary thread. John Stultz <john.stultz@linaro.org> - 2016-02-05 21:30 +0100
      Re: [PATCH] prctl: Add PR_SET_TIMERSLACK_PID for setting timer  slack of an arbitrary thread. Andrew Morton <akpm@linux-foundation.org> - 2016-02-05 21:40 +0100
        Re: [PATCH] prctl: Add PR_SET_TIMERSLACK_PID for setting timer slack  of an arbitrary thread. John Stultz <john.stultz@linaro.org> - 2016-02-05 21:40 +0100
          Re: [PATCH] prctl: Add PR_SET_TIMERSLACK_PID for setting timer slack  of an arbitrary thread. Kees Cook <keescook@chromium.org> - 2016-02-05 21:50 +0100
            Re: [PATCH] prctl: Add PR_SET_TIMERSLACK_PID for setting timer  slack of an arbitrary thread. Andrew Morton <akpm@linux-foundation.org> - 2016-02-05 22:00 +0100
              Re: [PATCH] prctl: Add PR_SET_TIMERSLACK_PID for setting timer slack  of an arbitrary thread. John Stultz <john.stultz@linaro.org> - 2016-02-05 23:40 +0100
                Re: [PATCH] prctl: Add PR_SET_TIMERSLACK_PID for setting timer slack  of an arbitrary thread. John Stultz <john.stultz@linaro.org> - 2016-02-06 02:00 +0100
                Re: [PATCH] prctl: Add PR_SET_TIMERSLACK_PID for setting timer  slack of an arbitrary thread. Andrew Morton <akpm@linux-foundation.org> - 2016-02-06 03:00 +0100
                Re: [PATCH] prctl: Add PR_SET_TIMERSLACK_PID for setting timer slack  of an arbitrary thread. John Stultz <john.stultz@linaro.org> - 2016-02-06 03:50 +0100
                Re: [PATCH] prctl: Add PR_SET_TIMERSLACK_PID for setting timer slack  of an arbitrary thread. Arjan van de Ven <arjan@linux.intel.com> - 2016-02-06 03:20 +0100
                Re: [PATCH] prctl: Add PR_SET_TIMERSLACK_PID for setting timer slack  of an arbitrary thread. Arjan van de Ven <arjan@linux.intel.com> - 2016-02-06 04:00 +0100
                Re: [PATCH] prctl: Add PR_SET_TIMERSLACK_PID for setting timer slack  of an arbitrary thread. John Stultz <john.stultz@linaro.org> - 2016-02-06 04:00 +0100

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