[lkml]   [2018]   [Oct]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH v9 04/10] x86: refcount: prevent gcc distortions
On October 4, 2018 1:33:33 AM PDT, Ingo Molnar <> wrote:
>* Ingo Molnar <> wrote:
>> I'm also somewhat annoyed at the fact that this series carries a
>> of reviewed-by's and acked-by's, yet none of those reviewers found it
>> important to point out the large chasm that is gaping between
>> and reality.
>Another problem I just realized is that we now include
>arch/x86/kernel/macros.S in every
>translation pass when building the kernel, right?
>But arch/x86/kernel/macros.S expands to a pretty large hiearchy of
>header files:
> $ make arch/x86/kernel/macros.s
>$ cat $(grep include arch/x86/kernel/macros.s | cut -d\" -f2 | sort |
>uniq) | wc -l
> 4128
>That's 4,100 extra lines of code to be preprocessed for every
>translation unit, of
>which there are tens of thousands. More if other pieces of code get
>macrofied in
>this fasion in the future.
>If we assume that a typical distribution kernel build has ~20,000
>translation units
>then this change adds 82,560,000 more lines to be preprocessed, just to
>work around
>a stupid GCC bug?
>I'm totally unhappy about that. Can we do this without adding macros.S?
>It's also a pretty stupidly central file anyway that moves source code
>from where it's used.
> Ingo

It's not just for working around a stupid GCC bug, but it also has a huge potential for cleaning up the inline asm in general.

I would like to know if there is an actual number for the build overhead (an actual benchmark); I have asked for that once already.
Sent from my Android device with K-9 Mail. Please excuse my brevity.

 \ /
  Last update: 2018-10-04 10:41    [W:0.150 / U:0.868 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site