linux-kernel - Re: [PATCH 0/7] minmax: reduce compilation time

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAHk-=wj9GLHpMo=ikVYzXtnNBpFwG3YeCZHfWndj5_xm=19szg@mail.gmail.com>
Date: Sat, 27 Jul 2024 09:26:43 -0700
From: Linus Torvalds <torvalds@...uxfoundation.org>
To: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>
Cc: David Laight <David.Laight@...lab.com>, 
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, 
	"Matthew Wilcox (Oracle)" <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>, Arnd Bergmann <arnd@...nel.org>, 
	"Jason@...c4.com" <Jason@...c4.com>, "pedro.falcato@...il.com" <pedro.falcato@...il.com>, 
	Mateusz Guzik <mjguzik@...il.com>, "linux-mm@...ck.org" <linux-mm@...ck.org>
Subject: Re: [PATCH 0/7] minmax: reduce compilation time

On Sat, 27 Jul 2024 at 01:08, Lorenzo Stoakes
<lorenzo.stoakes@...cle.com> wrote:
>
> 62603617./drivers/staging/media/atomisp/pci/isp/kernels/ynr/ynr_1.0/ia_css_ynr.host.o.pre

Heh.

  Longest line is drivers/.../ia_css_ynr.host.c:71 (27785kB)

yeah, that's a single line that expands to 27MB in size.

And yes, that line is one single min(...) expression with arguments
that are then in turn macros with other nested min/max arguments.

See also drivers/staging/media/atomisp/pci/sh_css_frac.h.

On my fairly beefy (admittedly more cores than single-thread) machine,
just generating the preprocessor file takes just under 20s.

Building the object file is actually faster at "only" 8.5s for that
one file, because it uses the built-in preprocessor and never writes
it out, and most of the actual preprocessing result is trivial stuff
that gets thrown away immediately.

              Linus