Messages in this thread | | | Date | Tue, 16 Jul 2019 17:29:30 +0200 | From | Michal Koutný <> | Subject | Re: [PATCH v11 2/5] sched/core: uclamp: Propagate parent clamps |
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On Tue, Jul 16, 2019 at 03:07:06PM +0100, Patrick Bellasi <patrick.bellasi@arm.com> wrote: > That note comes from the previous review cycle and it's based on a > request from Tejun to align uclamp behaviors with the way the > delegation model is supposed to work. I saw and hopefully understood that reasoning -- uclamp.min has the protection semantics and uclamp.max the limit semantics.
However, what took me some time to comprehend when the effected uclamp.min and uclamp.max cross over, i.e. that uclamp.min is then bound by uclamp.max (besides parent's uclamp.min). Your commit message explains that and I think it's relevant for the kernel docs file itself.
> You right, the synchronization is introduced by a later patch: > > sched/core: uclamp: Update CPU's refcount on TG's clamp changes I saw that lock but didn't realize __setscheduler_uclamp() touches only task's struct uclamp_se, none of task_group's/css's (which is under uclamp_mutex). That seems correct.
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