LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Peter Zijlstra <peterz@infradead.org>
To: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Cc: sil2review@lists.osadl.org, kernelnewbies@kernelnewbies.org,
	Philipp Klocke <Phil_K97@gmx.de>,
	llvmlinux@lists.linuxfoundation.org,
	linux-kernel@vger.kernel.org, Ingo Molnar <mingo@redhat.com>,
	der.herr@hofr.at
Subject: Re: [PATCH] sched/fair: Change sched_feat(x) in !CONFIG_SCHED_DEBUG case
Date: Mon, 23 Apr 2018 11:45:30 +0200	[thread overview]
Message-ID: <20180423094530.GW4064@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <alpine.DEB.2.20.1804202303350.17045@alpaca>

On Fri, Apr 20, 2018 at 11:29:33PM +0200, Lukas Bulwahn wrote:
> 
> On Fri, 20 Apr 2018, Peter Zijlstra wrote:
> 
> > On Fri, Apr 20, 2018 at 06:29:07PM +0200, Philipp Klocke wrote:
> > > The gain is stopping a warning that clutters the output log of clang.
> > 
> > Well, you should not be using clang anyway. It is known to miscompile
> > the kernel.
> > 
> 
> There are some advantages of having a second compiler that can compile
> the kernel (https://lwn.net/Articles/734071/). Some people in the kernel 
> community and LLVM community are trying to get that to work.

Sure, not arguing against that. Just saying clang isn't there yet and it
has much bigger problems than a stray warning.

> We also want a zero-warning policy for clang, similar to gcc. 
> Hence, this motivates to have a look at those few clang warnings and come 
> up with patches for them.
> 
> This does not imply to make changes at any cost, and we need to determine 
> a proper patch to either change the source code, disable the warning in 
> the build script or annotate the file with some clang-specific pragmas.
> 
> To us, a minor change in the source sounded most reasonable after looking
> at all three possible patches. Philipp might need another iteration, but
> it generally looks sound to me if we get the details flattened out. 

Given the history of compiler warnings; I would really like to have some
text that explains why the warning is useful and should be worked
around.

To me the warning under discussion seems very dodgy and I would propose
to disable it entirely. Using a value other than 0/1 for boolean
expressions is fairly common, it being a compile time constant doesn't
seem to make much difference to me.



_______________________________________________
Kernelnewbies mailing list
Kernelnewbies@kernelnewbies.org
https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies

  reply	other threads:[~2018-04-23  9:45 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-16  8:54 Philipp Klocke
2018-04-18 13:49 ` Nicholas Mc Guire
2018-04-20  7:57 ` Peter Zijlstra
2018-04-20 16:29   ` Philipp Klocke
2018-04-20 16:51     ` Peter Zijlstra
2018-04-20 21:29       ` Lukas Bulwahn
2018-04-23  9:45         ` Peter Zijlstra [this message]
2018-04-20 10:34 ` Peter Zijlstra

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20180423094530.GW4064@hirez.programming.kicks-ass.net \
    --to=peterz@infradead.org \
    --cc=Phil_K97@gmx.de \
    --cc=der.herr@hofr.at \
    --cc=kernelnewbies@kernelnewbies.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=llvmlinux@lists.linuxfoundation.org \
    --cc=lukas.bulwahn@gmail.com \
    --cc=mingo@redhat.com \
    --cc=sil2review@lists.osadl.org \
    --subject='Re: [PATCH] sched/fair: Change sched_feat(x) in '\!'CONFIG_SCHED_DEBUG case' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).