From: Valentin Schneider <valentin.schneider@arm.com>
To: Vincent Guittot <vincent.guittot@linaro.org>
Cc: linux-kernel <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Dietmar Eggemann <Dietmar.Eggemann@arm.com>,
Tejun Heo <tj@kernel.org>,
Patrick Bellasi <patrick.bellasi@matbug.net>,
Suren Baghdasaryan <surenb@google.com>,
Quentin Perret <qperret@google.com>,
Qais Yousef <qais.yousef@arm.com>
Subject: Re: [PATCH v2] sched/uclamp: Fix overzealous type replacement
Date: Fri, 15 Nov 2019 17:10:05 +0000 [thread overview]
Message-ID: <2dce8a83-b358-d975-bf43-8088b3bc5557@arm.com> (raw)
In-Reply-To: <f4fcc45e-7609-3836-162a-0a1839134bcf@arm.com>
On 15/11/2019 14:29, Valentin Schneider wrote:
> On 15/11/2019 14:07, Vincent Guittot wrote:
>>> -static inline enum uclamp_id uclamp_none(enum uclamp_id clamp_id)
>>> +static inline unsigned int uclamp_none(enum uclamp_id clamp_id)
>>
>> Out of curiosity why uclamp decided to use unsigned int to manipulate
>> utilization instead of unsigned long which is the type of util_avg ?
>>
>
> I didn't stare at the discussion much, but I think it stems from the
> design choices behind struct uclamp_se: everything is crammed in an unsigned
> int bitfield. Let me see if I can find some relevant mails.
>
So I think a relevant mail is:
https://lore.kernel.org/lkml/20180912174236.GB24106@hirez.programming.kicks-ass.net/
Other than that, the uclamp_se.value field was 'int' in v1 and has been
'unsigned int' for all following versions. uclamp_bucket.value is a bitfield
of an 'unsigned long' just because we want more headroom for the tasks count,
AFAICT.
next prev parent reply other threads:[~2019-11-15 17:10 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-15 10:39 Valentin Schneider
2019-11-15 14:07 ` Vincent Guittot
2019-11-15 14:29 ` Valentin Schneider
2019-11-15 17:10 ` Valentin Schneider [this message]
2019-11-15 17:34 ` Vincent Guittot
2019-11-15 20:21 ` Peter Zijlstra
2019-11-15 17:38 ` Vincent Guittot
2019-11-17 9:50 ` [tip: sched/core] " tip-bot2 for Valentin Schneider
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