From: Stefan Wahren <wahrenst@gmx.net>
To: Will Deacon <will@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>,
Nick Desaulniers <ndesaulniers@google.com>,
Russell King - ARM Linux admin <linux@armlinux.org.uk>,
Masahiro Yamada <yamada.masahiro@socionext.com>,
Nicolas Saenz Julienne <nsaenzjulienne@suse.de>,
Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>,
linux-arch <linux-arch@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Kees Cook <keescook@google.com>, Arnd Bergmann <arnd@arndb.de>,
clang-built-linux <clang-built-linux@googlegroups.com>
Subject: Re: [PATCH] compiler: enable CONFIG_OPTIMIZE_INLINING forcibly
Date: Sat, 12 Oct 2019 12:15:42 +0200 [thread overview]
Message-ID: <35643c7e-94e9-e410-543b-a7de17b59a32@gmx.net> (raw)
In-Reply-To: <20191003163606.iqzcxvghaw7hdqb5@willie-the-truck>
Hi,
Am 03.10.19 um 18:36 schrieb Will Deacon:
> On Wed, Oct 02, 2019 at 01:39:40PM -0700, Linus Torvalds wrote:
>> On Wed, Oct 2, 2019 at 5:56 AM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
>>>> Then use the C preprocessor to force the inlining. I'm sorry it's not
>>>> as pretty as static inline functions.
>>> Which makes us lose the baby^H^H^H^Htype checking performed
>>> on function parameters, requiring to add more ugly checks.
>> I'm 100% agreed on this.
>>
>> If the inline change is being pushed by people who say "you should
>> have used macros instead if you wanted inlining", then I will just
>> revert that stupid commit that is causing problems.
>>
>> No, the preprocessor is not the answer.
>>
>> That said, code that relies on inlining for _correctness_ should use
>> "__always_inline" and possibly even have a comment about why.
>>
>> But I am considering just undoing commit 9012d011660e ("compiler:
>> allow all arches to enable CONFIG_OPTIMIZE_INLINING") entirely. The
>> advantages are questionable, and when the advantages are balanced
>> against actual regressions and the arguments are "use macros", that
>> just shows how badly thought out this was.
> It's clear that opinions are divided on this issue, but you can add
> an enthusiastic:
>
> Acked-by: Will Deacon <will@kernel.org>
>
> if you go ahead with the revert. I'm all for allowing the compiler to
> make its own inlining decisions, but not when the potential for
> miscompilation isn't fully understood and the proposed alternatives turn
> the source into an unreadable mess. Perhaps we can do something different
> for 5.5 (arch opt-in? clang only? invert the logic? work to move functions
> over to __always_inline /before/ flipping the CONFIG option? ...?)
what's the status on this?
In need to prepare my pull requests for 5.5 and all recent kernelci
targets (including linux-next) with bcm2835_defconfig are still broken.
Stefan
>
> Will
next prev parent reply other threads:[~2019-10-12 10:15 UTC|newest]
Thread overview: 98+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-30 3:43 [PATCH] compiler: enable CONFIG_OPTIMIZE_INLINING forcibly Masahiro Yamada
2019-08-30 3:43 ` Masahiro Yamada
2019-08-30 20:54 ` Nick Desaulniers
2019-08-30 20:54 ` Nick Desaulniers
2019-09-26 8:54 ` Geert Uytterhoeven
2019-09-26 8:54 ` Geert Uytterhoeven
2019-09-26 9:02 ` Masahiro Yamada
2019-09-26 9:02 ` Masahiro Yamada
2019-09-26 9:26 ` Geert Uytterhoeven
2019-09-26 9:26 ` Geert Uytterhoeven
2019-09-26 9:46 ` Masahiro Yamada
2019-09-26 9:46 ` Masahiro Yamada
2019-09-27 10:43 ` Nicolas Saenz Julienne
2019-09-27 10:43 ` Nicolas Saenz Julienne
2019-09-27 10:59 ` Charles Keepax
2019-09-27 10:59 ` Charles Keepax
2019-09-27 22:08 ` Nick Desaulniers
2019-09-27 22:08 ` Nick Desaulniers
2019-09-27 22:38 ` Linus Torvalds
2019-09-27 22:38 ` Linus Torvalds
2019-09-30 11:26 ` Will Deacon
2019-09-30 11:26 ` Will Deacon
2019-09-30 12:05 ` Masahiro Yamada
2019-09-30 12:05 ` Masahiro Yamada
2019-09-30 12:18 ` Will Deacon
2019-09-30 12:18 ` Will Deacon
2019-09-30 21:50 ` Nick Desaulniers
2019-09-30 21:50 ` Nick Desaulniers
2019-09-30 22:08 ` Miguel Ojeda
2019-09-30 22:08 ` Miguel Ojeda
2019-09-30 22:34 ` Nick Desaulniers
2019-09-30 22:34 ` Nick Desaulniers
2019-10-01 9:28 ` Will Deacon
2019-10-01 9:28 ` Will Deacon
2019-10-01 16:32 ` Nick Desaulniers
2019-10-01 16:32 ` Nick Desaulniers
2019-10-01 17:01 ` Will Deacon
2019-10-01 17:01 ` Will Deacon
2019-10-01 17:44 ` Nick Desaulniers
2019-10-01 17:44 ` Nick Desaulniers
2019-10-01 17:55 ` Russell King - ARM Linux admin
2019-10-01 17:55 ` Russell King - ARM Linux admin
2019-10-01 18:00 ` Nick Desaulniers
2019-10-01 18:00 ` Nick Desaulniers
2019-10-01 18:14 ` Russell King - ARM Linux admin
2019-10-01 18:14 ` Russell King - ARM Linux admin
2019-10-01 20:21 ` Nick Desaulniers
2019-10-01 20:21 ` Nick Desaulniers
2019-10-01 20:53 ` Arnd Bergmann
2019-10-01 20:53 ` Arnd Bergmann
2019-10-01 21:06 ` Miguel Ojeda
2019-10-01 21:06 ` Miguel Ojeda
2019-10-01 21:14 ` Nick Desaulniers
2019-10-01 21:14 ` Nick Desaulniers
2019-10-01 20:59 ` Russell King - ARM Linux admin
2019-10-01 20:59 ` Russell King - ARM Linux admin
2019-10-01 21:26 ` Russell King - ARM Linux admin
2019-10-01 21:26 ` Russell King - ARM Linux admin
2019-10-01 21:32 ` Nick Desaulniers
2019-10-01 21:32 ` Nick Desaulniers
2019-10-01 21:58 ` Russell King - ARM Linux admin
2019-10-01 21:58 ` Russell King - ARM Linux admin
2019-10-02 12:55 ` Geert Uytterhoeven
2019-10-02 12:55 ` Geert Uytterhoeven
2019-10-02 18:51 ` Will Deacon
2019-10-02 18:51 ` Will Deacon
2019-10-02 20:39 ` Linus Torvalds
2019-10-02 20:39 ` Linus Torvalds
2019-10-03 2:10 ` Masahiro Yamada
2019-10-03 2:10 ` Masahiro Yamada
2019-10-03 17:01 ` Linus Torvalds
2019-10-03 17:01 ` Linus Torvalds
2019-10-03 17:08 ` Linus Torvalds
2019-10-03 17:08 ` Linus Torvalds
2019-10-03 17:23 ` Masahiro Yamada
2019-10-03 17:23 ` Masahiro Yamada
2019-10-03 17:29 ` Linus Torvalds
2019-10-03 17:29 ` Linus Torvalds
2019-10-03 20:21 ` Miguel Ojeda
2019-10-03 20:21 ` Miguel Ojeda
2019-10-04 7:37 ` Geert Uytterhoeven
2019-10-04 7:37 ` Geert Uytterhoeven
2019-10-03 16:36 ` Will Deacon
2019-10-03 16:36 ` Will Deacon
2019-10-12 10:15 ` Stefan Wahren [this message]
2019-10-12 10:15 ` Stefan Wahren
2019-10-12 11:12 ` Masahiro Yamada
2019-10-12 11:12 ` Masahiro Yamada
2019-10-12 14:45 ` Russell King - ARM Linux admin
2019-10-12 14:45 ` Russell King - ARM Linux admin
2019-10-01 9:39 ` Masahiro Yamada
2019-10-01 9:39 ` Masahiro Yamada
2019-10-01 10:40 ` Will Deacon
2019-10-01 10:40 ` Will Deacon
2019-09-27 10:58 ` Nicolas Saenz Julienne
2019-09-27 10:58 ` Nicolas Saenz Julienne
2019-09-30 6:04 ` Masahiro Yamada
2019-09-30 6:04 ` Masahiro Yamada
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