From: Matthias Kaehlcke <mka@chromium.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>,
Andy Lutomirski <luto@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H . Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, LKML <linux-kernel@vger.kernel.org>,
Manoj Gupta <manojgupta@chromium.org>,
Tiancong Wang <tcwang@chromium.org>,
Stephen Hines <srhines@google.com>,
clang-built-linux@googlegroups.com,
Masahiro Yamada <yamada.masahiro@socionext.com>
Subject: Re: [PATCH] x86/vdso: include generic __lshrdi3 in 32-bit vDSO
Date: Mon, 18 Mar 2019 13:44:35 -0700 [thread overview]
Message-ID: <20190318204435.GH112750@google.com> (raw)
In-Reply-To: <20190318171604.GU6058@hirez.programming.kicks-ass.net>
Hi Peter,
On Mon, Mar 18, 2019 at 06:16:04PM +0100, Peter Zijlstra wrote:
> On Mon, Mar 18, 2019 at 10:09:37AM -0700, Nick Desaulniers wrote:
> > On Fri, Mar 15, 2019 at 3:29 PM Matthias Kaehlcke <mka@chromium.org> wrote:
> > > On Fri, Mar 15, 2019 at 02:31:09PM -0700, 'Nick Desaulniers' via Clang Built Linux wrote:
> > > > Is there a config I can set to reproduce this, in order to help
> > > > test?
> > >
> > > I encountered it with a Chrome OS specific configuration, but a
> > > defconfig should do.
> >
> > defconfig selects CONFIG_OPTIMIZE_FOR_PERFORMANCE=y. I needed to
> > select CONFIG_CC_OPTIMIZE_FOR_SIZE=y to repro. My CI is simply
> > running defconfigs, which is why I didn't catch this.
>
> I suspect the right fix is to make clang use -Os and abolish that -Oz
> madness.
You have a point, enabling -Oz (aggressive optimization for size)
doesn't seem a good choice for the entire kernel.
I'll send a patch to change it (back) to -Os.
Matthias
next prev parent reply other threads:[~2019-03-18 20:44 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-15 19:54 [PATCH] x86/vdso: include generic __lshrdi3 in 32-bit vDSO Matthias Kaehlcke
2019-03-15 21:31 ` Nick Desaulniers
2019-03-15 22:29 ` Matthias Kaehlcke
2019-03-15 23:18 ` hpa
2019-03-18 8:59 ` Peter Zijlstra
2019-03-18 17:09 ` Nick Desaulniers
2019-03-18 17:16 ` Peter Zijlstra
2019-03-18 20:44 ` Matthias Kaehlcke [this message]
2019-03-18 23:03 ` Peter Zijlstra
2019-03-20 14:06 ` Masahiro Yamada
2019-03-20 13:55 ` Masahiro Yamada
2019-03-20 15:45 ` Matthias Kaehlcke
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