From: Peter Zijlstra <peterz@infradead.org>
To: David Malcolm <dmalcolm@redhat.com>
Cc: Ard Biesheuvel <ardb@kernel.org>,
linux-toolchains@vger.kernel.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Jason Baron <jbaron@akamai.com>,
"Steven Rostedt (VMware)" <rostedt@goodmis.org>,
yuanzhaoxiong@baidu.com
Subject: Re: static_branch/jump_label vs branch merging
Date: Thu, 22 Apr 2021 13:48:39 +0200 [thread overview]
Message-ID: <YIFilwwzWiSDZU6b@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20210409213949.GA33256@worktop.programming.kicks-ass.net>
On Fri, Apr 09, 2021 at 11:39:49PM +0200, Peter Zijlstra wrote:
> On Fri, Apr 09, 2021 at 05:07:15PM -0400, David Malcolm wrote:
>
> > You've built a very specific thing out of asm-goto to fulfil the tough
> > requirements you outlined above - as well as the nops, there's a thing
> > in another section to contend with.
> >
> > How to merge these asm-goto constructs?
>
> By calling the function less, you emit less of them. Which then brings
> us back to the whole pure/const thing.
>
> > Doing so feels very special-case to the kernel and not something that
> > other GCC users would find useful.
>
> Doesn't it boil down to 'fixing' the pure/const vs asm-goto interaction?
> I could imagine that having that interaction fixed could allow other
> creative uses.
Here is another variant:
https://lore.kernel.org/lkml/830177B0-45E0-4768-80AB-A99B85D3A52F@baidu.com/
Can we please have a __pure__ attribute that is prescriptive and not a
hint the compiler is free to ignore for $raisins ?
next prev parent reply other threads:[~2021-04-22 11:49 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-08 16:52 static_branch/jump_label vs branch merging Peter Zijlstra
2021-04-09 9:57 ` Ard Biesheuvel
2021-04-09 10:55 ` Florian Weimer
2021-04-09 11:16 ` Peter Zijlstra
2021-04-09 19:33 ` Nick Desaulniers
2021-04-09 20:11 ` Peter Zijlstra
2021-04-10 17:02 ` Segher Boessenkool
2021-04-09 11:12 ` Peter Zijlstra
2021-04-09 11:55 ` David Malcolm
2021-04-09 12:03 ` Peter Zijlstra
2021-04-09 13:01 ` Peter Zijlstra
2021-04-09 13:13 ` Peter Zijlstra
2021-04-09 13:48 ` David Malcolm
2021-04-09 18:40 ` Peter Zijlstra
2021-04-09 19:21 ` David Malcolm
2021-04-09 20:09 ` Peter Zijlstra
2021-04-09 21:07 ` David Malcolm
2021-04-09 21:39 ` Peter Zijlstra
2021-04-22 11:48 ` Peter Zijlstra [this message]
2021-04-22 17:08 ` Segher Boessenkool
2021-04-22 17:49 ` Peter Zijlstra
2021-04-22 18:31 ` Segher Boessenkool
2021-04-26 17:13 ` Peter Zijlstra
2021-04-10 12:44 ` David Laight
2021-04-09 13:03 ` Segher Boessenkool
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