linux-kernel - Re: [PATCH v2 1/8] minmax: Put all the clamp() definitions together

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Message-ID: <CAHk-=whNTuPVeOSB6bG7YRXeYym9anS2QawRHEKRJe2MQuOPPA@mail.gmail.com>
Date: Tue, 30 Jul 2024 16:03:36 -0700
From: Linus Torvalds <torvalds@...uxfoundation.org>
To: David Laight <David.Laight@...lab.com>
Cc: Arnd Bergmann <arnd@...nel.org>, 
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, Jens Axboe <axboe@...nel.dk>, 
	Matthew Wilcox <willy@...radead.org>, Christoph Hellwig <hch@...radead.org>, 
	Andrew Morton <akpm@...ux-foundation.org>, 
	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>, 
	Dan Carpenter <dan.carpenter@...aro.org>, "Jason A . Donenfeld" <Jason@...c4.com>, 
	"pedro.falcato@...il.com" <pedro.falcato@...il.com>, Mateusz Guzik <mjguzik@...il.com>, 
	"linux-mm@...ck.org" <linux-mm@...ck.org>, Lorenzo Stoakes <lorenzo.stoakes@...cle.com>
Subject: Re: [PATCH v2 1/8] minmax: Put all the clamp() definitions together

On Tue, 30 Jul 2024 at 15:44, Linus Torvalds
<torvalds@...uxfoundation.org> wrote:
>
> Does this work for you?

It seems to at least build cleanly here, but I'm not claiming it's all
that great.

The nested __cmp() is still rather less than optimal from an expansion
standpoint, but at least it expands only those unique temporaries.

[ Side note: having not looked at a lot of the resulting pre-processed
mess, I'm not convinced it really helps to make those unique names so
long.

  The whole "__UNIQUE_ID_" prefix looks good once, but to some degree
it actually hides the important part, which is the actual prefix and
the unique number.

  But honestly, nobody ever looks at this part normally, so it
probably doesn't matter ]

It might be possible to cut down on that by doing them in series
instead of nested, but I think that would require something like
generating a fourth unique name, and something along the lines of

    __auto_type u4 = __cmp(op, ux, uy); __cmp(op, u4, uz);

as that last line.

And no, I did *not* try that, and there might be something I'm missing.

        Linus