From: David Laight <David.Laight@ACULAB.COM>
To: 'Jiri Slaby' <jirislaby@gmail.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.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 13:34:36 +0000 [thread overview]
Message-ID: <147531551ec54a558c91bbef47f035c8@AcuMS.aculab.com> (raw)
In-Reply-To: <18c6df0d-45ed-450c-9eda-95160a2bbb8e@gmail.com>
From: Jiri Slaby <jirislaby@gmail.com>
> Sent: 08 January 2024 11:46
>
> Hi,
>
> On 18. 09. 23, 10:14, David Laight wrote:
> > The min() (etc) functions in minmax.h require that the arguments have
> > exactly the same types.
> >
> > However when the type check fails, rather than look at the types and
> > fix the type of a variable/constant, everyone seems to jump on min_t().
> > In reality min_t() ought to be rare - when something unusual is being
> > done, not normality.
> ...
> > David Laight (5):
> > minmax: Add umin(a, b) and umax(a, b)
> > minmax: Allow min()/max()/clamp() if the arguments have the same
> > signedness.
> > minmax: Fix indentation of __cmp_once() and __clamp_once()
> > minmax: Allow comparisons of 'int' against 'unsigned char/short'.
> > minmax: Relax check to allow comparison between unsigned arguments and
> > signed constants.
>
> This slows down the build and increases the build memory consumption so
> that it causes OOMs.
>
> In particular 6.7:
> $ time make drivers/media/pci/solo6x10/solo6x10-p2m.i
> ...
> CPP [M] drivers/media/pci/solo6x10/solo6x10-p2m.i
> real 0m45,002s
> user 0m40,840s
> sys 0m5,922s
>
>
> $ git revert 867046cc7027703f60a46339ffde91a1970f2901
> $ time make drivers/media/pci/solo6x10/solo6x10-p2m.i
> ...
> CPP [M] drivers/media/pci/solo6x10/solo6x10-p2m.i
> real 0m11,132s
> user 0m9,737s
> sys 0m1,415s
>
>
> $ git revert 4ead534fba42fc4fd41163297528d2aa731cd121
> $ time make drivers/media/pci/solo6x10/solo6x10-p2m.i
> ...
> CPP [M] drivers/media/pci/solo6x10/solo6x10-p2m.i
> real 0m3,711s
> user 0m3,041s
> sys 0m0,710s
>
>
>
> Note it's only a preprocessor run. If you run a compiler on top of that,
> it even dies.
>
> There is nothing special in that file, just:
> if (SOLO_SDRAM_END(solo_dev) > solo_dev->sdram_size) {
>
> which at some point expands to
> max(__SOLO_JPEG_MIN_SIZE(__solo), \
> min((__solo->sdram_size - SOLO_JPEG_EXT_ADDR(__solo)),
> 0x00ff0000))
>
> and that expands to a lot of stuff.
>
> Note that _line_ is 519 kbytes on 6.6 already. And 6 MB on 6.7.
Even with trivial min() max() it is 7.5k (piped through xargs -s72):
(see https://godbolt.org/z/rzE39YodW)
The 'explosion' happens because there are nested max(a, min(b, c)).
I think: max(a, min(max(b, min(c, d)), e))
I actually can't help feeling that is the driver ever uses
any of these values they ought to be saved during initialisation.
That would likely save a lot of code later - as well as shrinking
this test to something sane.
return ((((((((0x00000000 + 0x00480000) + ((solo->type == 1 ?
0x10000 : 0x20000) * 32)) + 0x00080000) + 0x00010000) +
((((solo->sdram_size <= (32 << 20)) ? 4 : 16) + 1) * (18 << 16)))
+ (0x00140000 * solo->nr_chans * 2)) + (((solo->nr_chans *
0x00080000)) > (((((solo->sdram_size - ((((((0x00000000 +
0x00480000) + ((solo->type == 1 ? 0x10000 : 0x20000) * 32)) +
0x00080000) + 0x00010000) + ((((solo->sdram_size <= (32 << 20)) ?
4 : 16) + 1) * (18 << 16))) + (0x00140000 * solo->nr_chans * 2)))
- (solo->nr_chans * 0x00080000))) < (0x00ff0000) ?
(((solo->sdram_size - ((((((0x00000000 + 0x00480000) +
((solo->type == 1 ? 0x10000 : 0x20000) * 32)) + 0x00080000) +
0x00010000) + ((((solo->sdram_size <= (32 << 20)) ? 4 : 16) + 1) *
(18 << 16))) + (0x00140000 * solo->nr_chans * 2))) -
(solo->nr_chans * 0x00080000))) : (0x00ff0000))) ?
((solo->nr_chans * 0x00080000)) : (((((solo->sdram_size -
((((((0x00000000 + 0x00480000) + ((solo->type == 1 ? 0x10000 :
0x20000) * 32)) + 0x00080000) + 0x00010000) + ((((solo->sdram_size
<= (32 << 20)) ? 4 : 16) + 1) * (18 << 16))) + (0x00140000 *
solo->nr_chans * 2))) - (solo->nr_chans * 0x00080000))) <
(0x00ff0000) ? (((solo->sdram_size - ((((((0x00000000 +
0x00480000) + ((solo->type == 1 ? 0x10000 : 0x20000) * 32)) +
0x00080000) + 0x00010000) + ((((solo->sdram_size <= (32 << 20)) ?
4 : 16) + 1) * (18 << 16))) + (0x00140000 * solo->nr_chans * 2)))
- (solo->nr_chans * 0x00080000))) : (0x00ff0000))))) +
(((solo->nr_chans * 0x00080000)) > ((((solo->sdram_size -
(((((((0x00000000 + 0x00480000) + ((solo->type == 1 ? 0x10000 :
0x20000) * 32)) + 0x00080000) + 0x00010000) + ((((solo->sdram_size
<= (32 << 20)) ? 4 : 16) + 1) * (18 << 16))) + (0x00140000 *
solo->nr_chans * 2)) + (((solo->nr_chans * 0x00080000)) >
(((((solo->sdram_size - ((((((0x00000000 + 0x00480000) +
((solo->type == 1 ? 0x10000 : 0x20000) * 32)) + 0x00080000) +
0x00010000) + ((((solo->sdram_size <= (32 << 20)) ? 4 : 16) + 1) *
(18 << 16))) + (0x00140000 * solo->nr_chans * 2))) -
(solo->nr_chans * 0x00080000))) < (0x00ff0000) ?
(((solo->sdram_size - ((((((0x00000000 + 0x00480000) +
((solo->type == 1 ? 0x10000 : 0x20000) * 32)) + 0x00080000) +
0x00010000) + ((((solo->sdram_size <= (32 << 20)) ? 4 : 16) + 1) *
(18 << 16))) + (0x00140000 * solo->nr_chans * 2))) -
(solo->nr_chans * 0x00080000))) : (0x00ff0000))) ?
((solo->nr_chans * 0x00080000)) : (((((solo->sdram_size -
((((((0x00000000 + 0x00480000) + ((solo->type == 1 ? 0x10000 :
0x20000) * 32)) + 0x00080000) + 0x00010000) + ((((solo->sdram_size
<= (32 << 20)) ? 4 : 16) + 1) * (18 << 16))) + (0x00140000 *
solo->nr_chans * 2))) - (solo->nr_chans * 0x00080000))) <
(0x00ff0000) ? (((solo->sdram_size - ((((((0x00000000 +
0x00480000) + ((solo->type == 1 ? 0x10000 : 0x20000) * 32)) +
0x00080000) + 0x00010000) + ((((solo->sdram_size <= (32 << 20)) ?
4 : 16) + 1) * (18 << 16))) + (0x00140000 * solo->nr_chans * 2)))
- (solo->nr_chans * 0x00080000))) : (0x00ff0000))))))) <
(0x00ff0000) ? ((solo->sdram_size - (((((((0x00000000 +
0x00480000) + ((solo->type == 1 ? 0x10000 : 0x20000) * 32)) +
0x00080000) + 0x00010000) + ((((solo->sdram_size <= (32 << 20)) ?
4 : 16) + 1) * (18 << 16))) + (0x00140000 * solo->nr_chans * 2)) +
(((solo->nr_chans * 0x00080000)) > (((((solo->sdram_size -
((((((0x00000000 + 0x00480000) + ((solo->type == 1 ? 0x10000 :
0x20000) * 32)) + 0x00080000) + 0x00010000) + ((((solo->sdram_size
<= (32 << 20)) ? 4 : 16) + 1) * (18 << 16))) + (0x00140000 *
solo->nr_chans * 2))) - (solo->nr_chans * 0x00080000))) <
(0x00ff0000) ? (((solo->sdram_size - ((((((0x00000000 +
0x00480000) + ((solo->type == 1 ? 0x10000 : 0x20000) * 32)) +
0x00080000) + 0x00010000) + ((((solo->sdram_size <= (32 << 20)) ?
4 : 16) + 1) * (18 << 16))) + (0x00140000 * solo->nr_chans * 2)))
- (solo->nr_chans * 0x00080000))) : (0x00ff0000))) ?
((solo->nr_chans * 0x00080000)) : (((((solo->sdram_size -
((((((0x00000000 + 0x00480000) + ((solo->type == 1 ? 0x10000 :
0x20000) * 32)) + 0x00080000) + 0x00010000) + ((((solo->sdram_size
<= (32 << 20)) ? 4 : 16) + 1) * (18 << 16))) + (0x00140000 *
solo->nr_chans * 2))) - (solo->nr_chans * 0x00080000))) <
(0x00ff0000) ? (((solo->sdram_size - ((((((0x00000000 +
0x00480000) + ((solo->type == 1 ? 0x10000 : 0x20000) * 32)) +
0x00080000) + 0x00010000) + ((((solo->sdram_size <= (32 << 20)) ?
4 : 16) + 1) * (18 << 16))) + (0x00140000 * solo->nr_chans * 2)))
- (solo->nr_chans * 0x00080000))) : (0x00ff0000))))))) :
(0x00ff0000))) ? ((solo->nr_chans * 0x00080000)) :
((((solo->sdram_size - (((((((0x00000000 + 0x00480000) +
((solo->type == 1 ? 0x10000 : 0x20000) * 32)) + 0x00080000) +
0x00010000) + ((((solo->sdram_size <= (32 << 20)) ? 4 : 16) + 1) *
(18 << 16))) + (0x00140000 * solo->nr_chans * 2)) +
(((solo->nr_chans * 0x00080000)) > (((((solo->sdram_size -
((((((0x00000000 + 0x00480000) + ((solo->type == 1 ? 0x10000 :
0x20000) * 32)) + 0x00080000) + 0x00010000) + ((((solo->sdram_size
<= (32 << 20)) ? 4 : 16) + 1) * (18 << 16))) + (0x00140000 *
solo->nr_chans * 2))) - (solo->nr_chans * 0x00080000))) <
(0x00ff0000) ? (((solo->sdram_size - ((((((0x00000000 +
0x00480000) + ((solo->type == 1 ? 0x10000 : 0x20000) * 32)) +
0x00080000) + 0x00010000) + ((((solo->sdram_size <= (32 << 20)) ?
4 : 16) + 1) * (18 << 16))) + (0x00140000 * solo->nr_chans * 2)))
- (solo->nr_chans * 0x00080000))) : (0x00ff0000))) ?
((solo->nr_chans * 0x00080000)) : (((((solo->sdram_size -
((((((0x00000000 + 0x00480000) + ((solo->type == 1 ? 0x10000 :
0x20000) * 32)) + 0x00080000) + 0x00010000) + ((((solo->sdram_size
<= (32 << 20)) ? 4 : 16) + 1) * (18 << 16))) + (0x00140000 *
solo->nr_chans * 2))) - (solo->nr_chans * 0x00080000))) <
(0x00ff0000) ? (((solo->sdram_size - ((((((0x00000000 +
0x00480000) + ((solo->type == 1 ? 0x10000 : 0x20000) * 32)) +
0x00080000) + 0x00010000) + ((((solo->sdram_size <= (32 << 20)) ?
4 : 16) + 1) * (18 << 16))) + (0x00140000 * solo->nr_chans * 2)))
- (solo->nr_chans * 0x00080000))) : (0x00ff0000))))))) <
(0x00ff0000) ? ((solo->sdram_size - (((((((0x00000000 +
0x00480000) + ((solo->type == 1 ? 0x10000 : 0x20000) * 32)) +
0x00080000) + 0x00010000) + ((((solo->sdram_size <= (32 << 20)) ?
4 : 16) + 1) * (18 << 16))) + (0x00140000 * solo->nr_chans * 2)) +
(((solo->nr_chans * 0x00080000)) > (((((solo->sdram_size -
((((((0x00000000 + 0x00480000) + ((solo->type == 1 ? 0x10000 :
0x20000) * 32)) + 0x00080000) + 0x00010000) + ((((solo->sdram_size
<= (32 << 20)) ? 4 : 16) + 1) * (18 << 16))) + (0x00140000 *
solo->nr_chans * 2))) - (solo->nr_chans * 0x00080000))) <
(0x00ff0000) ? (((solo->sdram_size - ((((((0x00000000 +
0x00480000) + ((solo->type == 1 ? 0x10000 : 0x20000) * 32)) +
0x00080000) + 0x00010000) + ((((solo->sdram_size <= (32 << 20)) ?
4 : 16) + 1) * (18 << 16))) + (0x00140000 * solo->nr_chans * 2)))
- (solo->nr_chans * 0x00080000))) : (0x00ff0000))) ?
((solo->nr_chans * 0x00080000)) : (((((solo->sdram_size -
((((((0x00000000 + 0x00480000) + ((solo->type == 1 ? 0x10000 :
0x20000) * 32)) + 0x00080000) + 0x00010000) + ((((solo->sdram_size
<= (32 << 20)) ? 4 : 16) + 1) * (18 << 16))) + (0x00140000 *
solo->nr_chans * 2))) - (solo->nr_chans * 0x00080000))) <
(0x00ff0000) ? (((solo->sdram_size - ((((((0x00000000 +
0x00480000) + ((solo->type == 1 ? 0x10000 : 0x20000) * 32)) +
0x00080000) + 0x00010000) + ((((solo->sdram_size <= (32 << 20)) ?
4 : 16) + 1) * (18 << 16))) + (0x00140000 * solo->nr_chans * 2)))
- (solo->nr_chans * 0x00080000))) : (0x00ff0000))))))) :
(0x00ff0000))))); }
David
>
> The file is 4.3M vs. 122M.
>
> Could you investigate/fix/revert (at least) the above two commits?
>
> thanks,
> --
> js
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
next prev parent reply other threads:[~2024-01-08 13:35 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-18 8:14 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 [this message]
2024-01-08 18:19 ` Linus Torvalds
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
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