Messages in this thread | | | From | Patrick Bellasi <> | Subject | Re: [PATCH v5 2/2] sched/uclamp: Protect uclamp fast path code with static key | Date | Tue, 30 Jun 2020 19:44:04 +0200 |
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On Tue, Jun 30, 2020 at 17:40:34 +0200, Qais Yousef <qais.yousef@arm.com> wrote...
> Hi Patrick > > On 06/30/20 16:55, Patrick Bellasi wrote: >> >> Hi Qais, >> sorry for commenting on v5 with a v6 already posted, but... >> ... I cannot keep up with your re-spinning rate ;) > > I classified that as a nit really and doesn't affect correctness. We have > different subjective view on what is better here. I did all the work in the > past 2 weeks and I think as the author of this patch I have the right to keep > my preference on subjective matters. I did consider your feedback and didn't > ignore it and improved the naming and added a comment to make sure there's no > confusion. > > We could nitpick the best name forever, but is it really that important?
Which leans toward confirming the impression I had while reading your previous response, i.e. you stopped reading at the name change observation, which would be _just_ a nit-picking, although still worth IMHO.
Instead, I went further and asked you to consider a different approach: not adding a new kernel symbol to represent a concept already there.
> I really don't see any added value for one approach or another here to start > a long debate about it.
Then you could have just called out that instead of silently ignoring the comment/proposal.
> The comments were small enough that I didn't see any controversy that > warrants holding the patches longer. I agreed with your proposal to use > uc_se->active and clarified why your other suggestions don't hold. > > You pointed that uclamp_is_enabled() confused you; and I responded that I'll > change the name.
Perhaps it would not confuse only me having 'something_enabled()' referring to 'something_used'.
> Sorry for not being explicit about answering the below, but > I thought my answer implied that I don't prefer it.
Your answer was about a name change, don't see correlation with a different approach... but should be just me.
>> >> Thus, perhaps we can just use the same pattern used by the >> >> sched_numa_balancing static key: >> >> >> >> $ git grep sched_numa_balancing >> >> kernel/sched/core.c:DEFINE_STATIC_KEY_FALSE(sched_numa_balancing); >> >> kernel/sched/core.c: static_branch_enable(&sched_numa_balancing); >> >> kernel/sched/core.c: static_branch_disable(&sched_numa_balancing); >> >> kernel/sched/core.c: int state = static_branch_likely(&sched_numa_balancing); >> >> kernel/sched/fair.c: if (!static_branch_likely(&sched_numa_balancing)) >> >> kernel/sched/fair.c: if (!static_branch_likely(&sched_numa_balancing)) >> >> kernel/sched/fair.c: if (!static_branch_likely(&sched_numa_balancing)) >> >> kernel/sched/fair.c: if (static_branch_unlikely(&sched_numa_balancing)) >> >> kernel/sched/sched.h:extern struct static_key_false sched_numa_balancing; >> >> >> >> IOW: unconditionally define sched_uclamp_used as non static in core.c, >> >> and use it directly on schedutil too. >> >> So, what about this instead of adding the (renamed) method above? > > I am sorry there's no written rule that says one should do it in a specific > way. And AFAIK both way are implemented in the kernel. I appreciate your > suggestion but as the person who did all the hard work, I think my preference > matters here too.
You sure know that sometime reviewing code can be an "hard work" too, so I would not go down that way at all with the discussion. Quite likely I have a different "subjective" view on how Open Source development works.
> And actually with my approach when uclamp is not compiled in there's no need to > define an extra variable; and since uclamp_is_used() is defined as false for > !CONFIG_UCLAMP_TASK, it'll help with DCE, so less likely to end up with dead > code that'll never run in the final binary.
Good, this is the simple and small reply I've politely asked for.
Best, Patrick
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