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From: Viresh Kumar <viresh.kumar@linaro.org>
To: Quentin Perret <qperret@google.com>
Cc: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
	tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
	x86@kernel.org, hpa@zytor.com, sudeep.holla@arm.com,
	gregkh@linuxfoundation.org, rafael@kernel.org,
	peterz@infradead.org, juri.lelli@redhat.com,
	vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
	rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de,
	mcgrof@kernel.org, keescook@chromium.org, yzaikin@google.com,
	fweisbec@gmail.com, tkjos@google.com, kernel-team@android.com
Subject: Re: [PATCH 00/14] Modularize schedutil
Date: Fri, 8 May 2020 11:03:59 +0530	[thread overview]
Message-ID: <20200508053359.ul5dbws6vkpdrbef@vireshk-i7> (raw)
In-Reply-To: <20200507181012.29791-1-qperret@google.com>

On 07-05-20, 19:09, Quentin Perret wrote:
> Android is trying very hard to use a single kernel image (commonly
> called Generic Kernel Image, or GKI), closely aligned with mainline, to
> run on all Android devices regardless of the vendor.
> 
> The GKI project intends to not only improve the status quo for Android
> users directly (less fragmentation simplifies updatability), but also
> to benefit upstream by forcing all vendors to agree on one common
> kernel, that we push hard to be aligned with mainline.
> 
> One challenge to implement GKI is to avoid bloating the kernel by
> compiling too many things in, especially given that different devices
> need different things. As such, anything that can be turned into a
> module helps GKI, by offering an alternative to having that component
> built-in. This is true for pretty much anything that can be made
> modular, including drivers as well as other kernel components, such as
> CPUFreq governors.
> 
> Indeed, in practice, Android devices often ship with only one CPUFreq
> governor enabled, and don't require any other that would simply waste
> memory for no benefits. All CPUFreq governors can already be built as
> modules with one notable exception: schedutil. Though popular in
> Android, some devices do not use schedutil, which is why it would be
> preferable to not have it unconditionally built in GKI. This series is
> an attempt to solve this problem, by making schedutil tristate.
> 
> While modularization is usually not something we want to see near the
> scheduler, it appeared to me as I wrote those patches that the
> particular case of schedutil was actually not too bad to implement.
> We already have to support switching governors at run-time, simply
> because userspace is free to do that, so the infrastructure for turning
> sugov on and off dynamically is already there. Loading the code a little
> later doesn't seem to make that a lot worse.
> 
> Patches 01-05 refactor some code to break the few dependencies on
> schedutil being builtin (notably EAS). Patches 06-12 export various
> symbols that schedutil needs when compiled as a module. And finally,
> patches 13-14 finish off the work by making the Kconfig tristate.

IMHO, you have over-broken the patches, like first two could be merged
together and all exports could have been done in a single patch, etc.
i.e. all related or similar changes together...

Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

-- 
viresh

  parent reply	other threads:[~2020-05-08  5:34 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-07 18:09 [PATCH 00/14] Modularize schedutil Quentin Perret
2020-05-07 18:09 ` [PATCH 01/14] sched: Provide sched_set_deadline() Quentin Perret
2020-05-07 18:10 ` [PATCH 02/14] sched: cpufreq: Use sched_set_deadline() from sugov Quentin Perret
2020-05-07 18:10 ` [PATCH 03/14] sched: cpufreq: Introduce 'want_eas' governor flag Quentin Perret
2020-05-07 18:10 ` [PATCH 04/14] sched: cpufreq: Move sched_cpufreq_governor_change() Quentin Perret
2020-05-08  5:35   ` Pavan Kondeti
2020-05-08 13:18     ` Quentin Perret
2020-05-07 18:10 ` [PATCH 05/14] sched: cpufreq: Move schedutil_cpu_util() Quentin Perret
2020-05-07 18:10 ` [PATCH 06/14] arch_topology: Export cpu_scale per-cpu array Quentin Perret
2020-05-07 18:10 ` [PATCH 07/14] kthread: Export kthread_bind_mask() Quentin Perret
2020-05-07 18:10 ` [PATCH 08/14] sched/core: Export runqueues per-cpu array Quentin Perret
2020-05-08  8:07   ` Peter Zijlstra
2020-05-08 10:04     ` Quentin Perret
2020-05-07 18:10 ` [PATCH 09/14] sched/cpufreq: Export cpufreq_this_cpu_can_update() Quentin Perret
2020-05-07 18:10 ` [PATCH 10/14] sched/fair: Export cpu_util_freq() Quentin Perret
2020-05-07 18:10 ` [PATCH 11/14] tick/sched: Export tick_nohz_get_idle_calls_cpu Quentin Perret
2020-05-07 18:10 ` [PATCH 12/14] x86: Export arch_scale_freq_key Quentin Perret
2020-05-07 18:10 ` [PATCH 13/14] sched: cpufreq: Use IS_ENABLED() for schedutil Quentin Perret
2020-05-08  5:30   ` Pavan Kondeti
2020-05-08 13:21     ` Quentin Perret
2020-05-09  2:43       ` Pavan Kondeti
2020-05-07 18:10 ` [PATCH 14/14] sched: cpufreq: Modularize schedutil Quentin Perret
2020-05-07 21:34 ` [PATCH 00/14] " Valentin Schneider
2020-05-08 13:15   ` Quentin Perret
2020-05-08 14:52     ` Valentin Schneider
2020-05-08  5:33 ` Viresh Kumar [this message]
2020-05-08 13:18   ` Quentin Perret
2020-05-08  8:11 ` Peter Zijlstra
2020-05-08 10:37   ` Greg KH
2020-05-08 11:16     ` Quentin Perret
2020-05-08 11:31       ` Peter Zijlstra
2020-05-08 13:05         ` Quentin Perret
2020-05-08 13:40           ` Rafael J. Wysocki
2020-05-11  9:00             ` Quentin Perret
2020-05-11 15:26               ` Rafael J. Wysocki
2020-05-12  9:21                 ` Quentin Perret
2020-05-12 10:25                   ` Rafael J. Wysocki
2020-05-12 13:58                     ` Quentin Perret
2020-05-12 14:08                       ` Rafael J. Wysocki
2020-05-12 15:11                         ` Quentin Perret
2020-05-12 15:30                           ` Rafael J. Wysocki
2020-05-12 15:49                             ` Joel Fernandes
2020-05-13  8:57                               ` Quentin Perret
2020-05-12 16:26                             ` Quentin Perret
2020-05-12 17:30                               ` Rafael J. Wysocki
2020-05-13  9:41                                 ` Quentin Perret
2020-05-13 10:02                                   ` Greg KH
2020-05-13 10:06                                     ` Quentin Perret
2020-05-13 10:24                                       ` Greg KH
2020-05-08 14:09           ` Peter Zijlstra
2020-05-11  9:12             ` Quentin Perret
2020-05-08 11:26     ` Peter Zijlstra
2020-05-11  5:21       ` Viresh Kumar

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