linux-kernel - RE: [PATCH next v4 0/5] minmax: Relax type checks in min() and max().

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Date: Fri, 19 Jan 2024 09:14:15 +0000
From: David Laight <David.Laight@...LAB.COM>
To: 'Jiri Slaby' <jirislaby@...nel.org>, Linus Torvalds
	<torvalds@...ux-foundation.org>
CC: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, "Andy
 Shevchenko" <andriy.shevchenko@...ux.intel.com>, Andrew Morton
	<akpm@...ux-foundation.org>, "Matthew Wilcox (Oracle)" <willy@...radead.org>,
	Christoph Hellwig <hch@...radead.org>, "Jason A. Donenfeld"
	<Jason@...c4.com>, linux-media <linux-media@...r.kernel.org>, Hans Verkuil
	<hverkuil@...all.nl>
Subject: RE: [PATCH next v4 0/5] minmax: Relax type checks in min() and max().

From: Jiri Slaby
> Sent: 19 January 2024 07:14
> 
> On 08. 01. 24, 19:19, Linus Torvalds wrote:
> > On Mon, 8 Jan 2024 at 03:46, Jiri Slaby <jirislaby@...il.com> wrote:
> >>
> >>     CPP [M] drivers/media/pci/solo6x10/solo6x10-p2m.i
> >> real    0m45,002s
> >>
> >> $ git revert 867046cc7027703f60a46339ffde91a1970f2901
> >>     CPP [M] drivers/media/pci/solo6x10/solo6x10-p2m.i
> >> real    0m11,132s
> >>
> >> $ git revert 4ead534fba42fc4fd41163297528d2aa731cd121
> >>     CPP [M] drivers/media/pci/solo6x10/solo6x10-p2m.i
> >> real    0m3,711s
> >
> > Ouch. Yeah, that's unfortunate. There's a lot of nested nasty macro
> > expansion there, but that timing is excessive.

As a matter of interest what are you compiling on?
I've since test compiled that file and don't even see a pause
in the makefile output - so well under a second to compile.

...
> > That said, I'm sure this thing exists to a smaller degree elsewhere. I
> > wonder if we could simplify our min/max type tests.
> I assume we don't care with solo fixed? Hans pointed out ath11k too.
> Even if there is size increase in the preproc file, I don't see much of
> compile time increase there.

I have got a few patches that reduce the cpp output size.
I'll post them after -rc1 is out.

Linus might need to take them directly since I've added min_const()
and removed the logic that generates 'const from const'.
That requires a trivial change to the 8 files (I've found) that
use min/max for sizing on-stack arrays between two patches.

	David

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