linux-kernel - Re: [PATCH v2 05/15] gpio: pxa: Use modern PM macros

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Message-ID: <aR22decsE0DYDUnS@xhacker>
Date: Wed, 19 Nov 2025 20:22:13 +0800
From: Jisheng Zhang <jszhang@...nel.org>
To: Robert Jarzmik <robert.jarzmik@...e.fr>
Cc: Andy Shevchenko <andy.shevchenko@...il.com>,
	Doug Berger <opendmb@...il.com>,
	Florian Fainelli <florian.fainelli@...adcom.com>,
	bcm-kernel-feedback-list@...adcom.com,
	Linus Walleij <linus.walleij@...aro.org>,
	Bartosz Golaszewski <brgl@...ev.pl>,
	Hoan Tran <hoan@...amperecomputing.com>,
	Andy Shevchenko <andy@...nel.org>, Daniel Palmer <daniel@...ngy.jp>,
	Romain Perier <romain.perier@...il.com>,
	Grygorii Strashko <grygorii.strashko@...com>,
	Santosh Shilimkar <ssantosh@...nel.org>,
	Kevin Hilman <khilman@...nel.org>,
	Kunihiko Hayashi <hayashi.kunihiko@...ionext.com>,
	Masami Hiramatsu <mhiramat@...nel.org>,
	Shubhrajyoti Datta <shubhrajyoti.datta@....com>,
	Srinivas Neeli <srinivas.neeli@....com>,
	Michal Simek <michal.simek@....com>, linux-gpio@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	linux-omap@...r.kernel.org
Subject: Re: [PATCH v2 05/15] gpio: pxa: Use modern PM macros

On Tue, Nov 18, 2025 at 11:03:41PM +0100, Robert Jarzmik wrote:
> Andy Shevchenko <andy.shevchenko@...il.com> writes:
> 
> > On Tue, Nov 18, 2025 at 2:50 AM Jisheng Zhang <jszhang@...nel.org>
> > wrote:
> > > 
> > > Use the modern PM macros for the suspend and resume functions to be
> > > automatically dropped by the compiler when CONFIG_PM or
> > > CONFIG_PM_SLEEP are disabled, without having to use #ifdef guards.
> ...zip...
> > 
> > > -#ifdef CONFIG_PM
> > >         unsigned long   saved_gplr;
> > >         unsigned long   saved_gpdr;
> > >         unsigned long   saved_grer;
> > >         unsigned long   saved_gfer;
> > > -#endif
> 
> Actually this is not equivalent to what was there before.
> 
> With Jisheng's patch, with CONFIG_PM disabled, he adds 16 bytes to the
> structure. You might thing today, 16 bytes is nothing. True, but on a
> 64MB RAM devices, it's something.

hmm, each controller adds 16bytes, then even on 100 controller platforms
1600bytes. 1600 Bytes/64MB ~= 0.238%. it's trival. And is there such platform?

>From another side, recently UP support is removed from the core sched,
that removing adds more .text and .data overhead, so if the users really
care about this kind of 16bytes, it means he(she) can't afford even the
16Bytes overhead, then I bet he(she) the always SMP in core sched, so
why not stick with the old kernel? What do you think?

> 
> That might not be a reason to reject the patch, but it's not only a
> "modernisation patch".
> 
> Cheers.
> 
> --
> Robert