netdev - Re: [PATCH 00/51] treewide: Switch to __pm_runtime_put

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Message-ID: <CAPDyKFpQVnF7eQv3dup8k-3EijnMjuveCG9sZ=Rpey1Y6MBJEg@mail.gmail.com>
Date: Tue, 8 Oct 2024 00:08:24 +0200
From: Ulf Hansson <ulf.hansson@...aro.org>
To: Laurent Pinchart <laurent.pinchart@...asonboard.com>
Cc: Sakari Ailus <sakari.ailus@...ux.intel.com>, dri-devel@...ts.freedesktop.org, 
	linux-kernel@...r.kernel.org, linux-bluetooth@...r.kernel.org, 
	linux-clk@...r.kernel.org, linux-crypto@...r.kernel.org, 
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	asahi@...ts.linux.dev, rafael@...nel.org, 
	Andy Shevchenko <andy.shevchenko@...il.com>
Subject: Re: [PATCH 00/51] treewide: Switch to __pm_runtime_put_autosuspend()

On Mon, 7 Oct 2024 at 20:49, Laurent Pinchart
<laurent.pinchart@...asonboard.com> wrote:
>
> Hi Ulf,
>
> On Fri, Oct 04, 2024 at 04:38:36PM +0200, Ulf Hansson wrote:
> > On Fri, 4 Oct 2024 at 11:41, Sakari Ailus <sakari.ailus@...ux.intel.com> wrote:
> > >
> > > Hello everyone,
> > >
> > > This set will switch the users of pm_runtime_put_autosuspend() to
> > > __pm_runtime_put_autosuspend() while the former will soon be re-purposed
> > > to include a call to pm_runtime_mark_last_busy(). The two are almost
> > > always used together, apart from bugs which are likely common. Going
> > > forward, most new users should be using pm_runtime_put_autosuspend().
> > >
> > > Once this conversion is done and pm_runtime_put_autosuspend() re-purposed,
> > > I'll post another set to merge the calls to __pm_runtime_put_autosuspend()
> > > and pm_runtime_mark_last_busy().
> >
> > That sounds like it could cause a lot of churns.
> >
> > Why not add a new helper function that does the
> > pm_runtime_put_autosuspend() and the pm_runtime_mark_last_busy()
> > things? Then we can start moving users over to this new interface,
> > rather than having this intermediate step?
>
> I think the API would be nicer if we used the shortest and simplest
> function names for the most common use cases. Following
> pm_runtime_put_autosuspend() with pm_runtime_mark_last_busy() is that
> most common use case. That's why I like Sakari's approach of repurposing
> pm_runtime_put_autosuspend(), and introducing
> __pm_runtime_put_autosuspend() for the odd cases where
> pm_runtime_mark_last_busy() shouldn't be called.

Okay, so the reason for this approach is because we couldn't find a
short and descriptive name that could be used in favor of
pm_runtime_put_autosuspend(). Let me throw some ideas at it and maybe
you like it - or not. :-)

I don't know what options you guys discussed, but to me the entire
"autosuspend"-suffix isn't really that necessary in my opinion. There
are more ways than calling pm_runtime_put_autosuspend() that triggers
us to use the RPM_AUTO flag for rpm_suspend(). For example, just
calling pm_runtime_put() has the similar effect.

Moreover, it's similar for pm_runtime_mark_last_busy(), it's called
during rpm_resume() too, for example. So why bother about having
"mark_last_busy" in the new name too.

That said, my suggestion is simply "pm_runtime_put_suspend".

If you don't like it, I will certainly not object to your current
approach, even if I think it leads to unnecessary churns.

[...]

Kind regards
Uffe