Messages in this thread | | | Date | Tue, 17 Nov 2020 11:23:46 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH v2] sched/uclamp: Allow to reset a task uclamp constraint value |
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On Sun, Nov 15, 2020 at 01:05:21PM +0800, Yun Hsiang wrote: > Hi Dietmar, > On Fri, Nov 13, 2020 at 12:34:54PM +0100, Dietmar Eggemann wrote: > > In case the user wants to stop controlling a uclamp constraint value > > for a task, use the magic value -1 in sched_util_{min,max} with the > > appropriate sched_flags (SCHED_FLAG_UTIL_CLAMP_{MIN,MAX}) to indicate > > the reset. > > > > The advantage over the 'additional flag' approach (i.e. introducing > > SCHED_FLAG_UTIL_CLAMP_RESET) is that no additional flag has to be > > exported via uapi. This avoids the need to document how this new flag > > has be used in conjunction with the existing uclamp related flags. > > > > The following subtle issue is fixed as well. When a uclamp constraint > > value is set on a !user_defined uclamp_se it is currently first reset > > and then set. > > Fix this by AND'ing !user_defined with !SCHED_FLAG_UTIL_CLAMP which > > stands for the 'sched class change' case. > > The related condition 'if (uc_se->user_defined)' moved from > > __setscheduler_uclamp() into uclamp_reset(). > > I think this is great, thanks! > Reviewed-by: Yun Hsiang <hsiang023167@gmail.com>
Thanks!
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