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Message-ID: <650bdb23-0875-4e19-9e3e-82337da6da00@kernel.org>
Date: Fri, 19 Jan 2024 08:14:14 +0100
From: Jiri Slaby <jirislaby@...nel.org>
To: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: David Laight <David.Laight@...lab.com>,
"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().
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.
>
> 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.
So can someone pick up 20240113183334.1690740-1-aurelien@...el32.net so
that we are done with this? I see neither Hans, nor Linus got to take it
yet.
> 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.
thanks,
--
js
suse labs
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