linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Linus Torvalds <torvalds@linux-foundation.org>
To: Jiri Slaby <jirislaby@gmail.com>
Cc: David Laight <David.Laight@aculab.com>,
	 "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	 Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	 Andrew Morton <akpm@linux-foundation.org>,
	"Matthew Wilcox (Oracle)" <willy@infradead.org>,
	 Christoph Hellwig <hch@infradead.org>,
	"Jason A. Donenfeld" <Jason@zx2c4.com>
Subject: Re: [PATCH next v4 0/5] minmax: Relax type checks in min() and max().
Date: Mon, 8 Jan 2024 10:19:07 -0800	[thread overview]
Message-ID: <CAHk-=wjvM5KiQFpbPMPXH-DcvheNcPGj+ThNEJVm+QL6n05A8A@mail.gmail.com> (raw)
In-Reply-To: <18c6df0d-45ed-450c-9eda-95160a2bbb8e@gmail.com>

On Mon, 8 Jan 2024 at 03:46, Jiri Slaby <jirislaby@gmail.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.

Sparse actually complains about that file:

  drivers/media/pci/solo6x10/solo6x10-p2m.c:309:13: error: too long
token expansion
  drivers/media/pci/solo6x10/solo6x10-p2m.c:310:17: error: too long
token expansion

and while that is a sparse limitation, it's still interesting. Having
that file expand to 122M is not ok.

In this case, I suspect the right thing to do is to simply not use
min()/max() in that header at all, but do something like

  --- a/drivers/media/pci/solo6x10/solo6x10-offsets.h
  +++ b/drivers/media/pci/solo6x10/solo6x10-offsets.h
  @@ -56,2 +56,5 @@

  +#define MIN(X, Y) ((X) < (Y) ? (X) : (Y))
  +#define MAX(X, Y) ((X) > (Y) ? (X) : (Y))
  +
   #define SOLO_MP4E_EXT_ADDR(__solo) \
  @@ -59,4 +62,4 @@
   #define SOLO_MP4E_EXT_SIZE(__solo) \
  -     max((..),                               \
  -         min(((..) - \
  +     MAX((..),                               \
  +         MIN(((..) - \
                 ..), 0x00ff0000))
  @@ -67,4 +70,4 @@
   #define SOLO_JPEG_EXT_SIZE(__solo) \
  -     max(..,                         \
  -         min(..)
  +     MAX(..,                         \
  +         MIN(..)

and avoid this issue.

That said, I'm sure this thing exists to a smaller degree elsewhere. I
wonder if we could simplify our min/max type tests..

             Linus

  parent reply	other threads:[~2024-01-08 18:19 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-18  8:14 [PATCH next v4 0/5] minmax: Relax type checks in min() and max() David Laight
2023-09-18  8:16 ` [PATCH next v4 1/5] minmax: Add umin(a, b) and umax(a, b) David Laight
2024-01-12 12:49   ` Dan Carpenter
2024-01-12 13:40     ` David Laight
2024-01-12 14:03       ` Dan Carpenter
2024-01-12 14:26         ` David Laight
2024-01-18 10:30           ` Dan Carpenter
2023-09-18  8:17 ` [PATCH next v4 2/5] minmax: Allow min()/max()/clamp() if the arguments have the same signedness David Laight
2023-09-18  8:17 ` [PATCH next v4 3/5] minmax: Fix indentation of __cmp_once() and __clamp_once() David Laight
2023-09-18  8:18 ` [PATCH next v4 4/5] minmax: Allow comparisons of 'int' against 'unsigned char/short' David Laight
2023-09-18  8:19 ` [PATCH next v4 5/5] minmax: Relax check to allow comparison between unsigned arguments and signed constants David Laight
2023-09-27 17:30 ` [PATCH next v4 0/5] minmax: Relax type checks in min() and max() Andrew Morton
2023-09-28  8:10   ` David Laight
2024-01-08 11:46 ` Jiri Slaby
2024-01-08 13:34   ` David Laight
2024-01-08 18:19   ` Linus Torvalds [this message]
2024-01-08 20:04     ` Linus Torvalds
2024-01-08 21:11       ` Linus Torvalds
2024-01-09  0:39         ` [PATCH next v4 0/5] minmax: Relax type checks in min() and max().^[[C John Stoffel
2024-01-09  6:54         ` [PATCH next v4 0/5] minmax: Relax type checks in min() and max() Jiri Slaby
2024-01-10  6:17         ` Stephen Rothwell
2024-01-10  9:03           ` David Laight
2024-01-10 19:35           ` Linus Torvalds
2024-01-10 22:58             ` David Laight
2024-01-20 21:33               ` Linus Torvalds
2024-01-21 22:18                 ` David Laight
2024-01-09  9:35     ` David Laight
2024-01-09  9:41     ` David Laight
2024-01-09 12:09     ` Kalle Valo
2024-01-19  7:14     ` Jiri Slaby
2024-01-19  8:23       ` Hans Verkuil
2024-01-19  9:14       ` David Laight
2024-01-12  9:13 ` Dan Carpenter
2024-01-12 12:16   ` David Laight
2024-01-12 12:40     ` Dan Carpenter

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to='CAHk-=wjvM5KiQFpbPMPXH-DcvheNcPGj+ThNEJVm+QL6n05A8A@mail.gmail.com' \
    --to=torvalds@linux-foundation.org \
    --cc=David.Laight@aculab.com \
    --cc=Jason@zx2c4.com \
    --cc=akpm@linux-foundation.org \
    --cc=andriy.shevchenko@linux.intel.com \
    --cc=hch@infradead.org \
    --cc=jirislaby@gmail.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=willy@infradead.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).