From: Nathan Chancellor <natechancellor@gmail.com>
To: Masahiro Yamada <masahiroy@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Arnd Bergmann <arnd@arndb.de>, Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
x86@kernel.org, clang-built-linux@googlegroups.com,
Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>,
sparclinux@vger.kernel.org, Andy Lutomirski <luto@kernel.org>,
Borislav Petkov <bp@alien8.de>,
"David S. Miller" <davem@davemloft.net>,
"H. Peter Anvin" <hpa@zytor.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 1/2] sparc,x86: vdso: remove meaningless undefining CONFIG_OPTIMIZE_INLINING
Date: Thu, 20 Feb 2020 10:41:55 -0700 [thread overview]
Message-ID: <20200220174155.GA40621@ubuntu-m2-xlarge-x86> (raw)
In-Reply-To: <20200220110807.32534-1-masahiroy@kernel.org>
On Thu, Feb 20, 2020 at 08:08:06PM +0900, Masahiro Yamada wrote:
> The code, #undef CONFIG_OPTIMIZE_INLINING, is not working as expected
> because <linux/compiler_types.h> is parsed before vclock_gettime.c
> since 28128c61e08e ("kconfig.h: Include compiler types to avoid missed
> struct attributes").
>
> Since then, <linux/compiler_types.h> is included really early by
> using the '-include' option. So, you cannot negate the decision of
> <linux/compiler_types.h> in this way.
>
> You can confirm it by checking the pre-processed code, like this:
>
> $ make arch/x86/entry/vdso/vdso32/vclock_gettime.i
>
> There is no difference with/without CONFIG_CC_OPTIMIZE_FOR_SIZE.
>
> It is about two years since 28128c61e08e. Nobody has reported a
> problem (or, nobody has even noticed the fact that this code is not
> working).
>
> It is ugly and unreliable to attempt to undefine a CONFIG option from
> C files, and anyway the inlining heuristic is up to the compiler.
>
> Just remove the broken code.
>
> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
> Acked-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
next prev parent reply other threads:[~2020-02-20 17:42 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-20 11:08 Masahiro Yamada
2020-02-20 11:08 ` [PATCH v2 2/2] compiler: Remove CONFIG_OPTIMIZE_INLINING entirely Masahiro Yamada
2020-02-20 17:42 ` Nathan Chancellor
2020-02-20 17:41 ` Nathan Chancellor [this message]
2020-03-19 7:20 ` [PATCH v2 1/2] sparc,x86: vdso: remove meaningless undefining CONFIG_OPTIMIZE_INLINING Masahiro Yamada
2020-04-03 5:57 ` Masahiro Yamada
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