From: Steven Rostedt <rostedt@goodmis.org>
To: Nathan Chancellor <natechancellor@gmail.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>,
Jason Gunthorpe <jgg@ziepe.ca>,
Masahiro Yamada <masahiroy@kernel.org>,
Michal Marek <michal.lkml@markovi.net>,
Arnd Bergmann <arnd@arndb.de>, Ingo Molnar <mingo@redhat.com>,
Jason Baron <jbaron@akamai.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Andrew Morton <akpm@linux-foundation.org>,
LKML <linux-kernel@vger.kernel.org>,
Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
linux-arch <linux-arch@vger.kernel.org>,
Linux Memory Management List <linux-mm@kvack.org>,
clang-built-linux <clang-built-linux@googlegroups.com>
Subject: Re: [PATCH 3/6] tracing: Wrap section comparison in tracer_alloc_buffers with COMPARE_SECTIONS
Date: Wed, 19 Feb 2020 14:43:33 -0500 [thread overview]
Message-ID: <20200219144333.1ce3f9ea@gandalf.local.home> (raw)
In-Reply-To: <20200219192249.GA8840@ubuntu-m2-xlarge-x86>
On Wed, 19 Feb 2020 12:22:49 -0700
Nathan Chancellor <natechancellor@gmail.com> wrote:
> Yes, thank you for the analysis and further discussion! I have done some
> rudimentary printk debugging in QEMU and it looks like these are produce
> the same value:
>
> __stop___trace_bprintk_fmt
> &__stop___trace_bprintk_fmt
> &__start___trace_bprintk_fmt[0]
>
> as well as
>
> __stop___trace_bprintk_fmt != __start___trace_bprintk_fmt
> &__stop___trace_bprintk_fmt != &__start___trace_bprintk_fmt
> &__stop___trace_bprintk_fmt[0] != &__start___trace_bprintk_fmt[0]
>
> I'll use the second one once I confirm this is true in all callspots
> with both Clang and GCC, since it looks cleaner. Let me know if there
> are any objections to that.
Myself and I'm sure others would be fine with this approach as it is
still readable. I was just against the encapsulating the logic in a
strange macro that killed readability.
I haven't looked at the resulting assembly from these, and will
currently take your word for it ;-) Of course, I will thoroughly test
any patches to this code to make sure it does not hurt functionality.
-- Steve
next prev parent reply other threads:[~2020-02-19 19:43 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-19 4:54 [PATCH 0/6] Silence some instances of -Wtautological-compare and enable globally Nathan Chancellor
2020-02-19 4:54 ` [PATCH 1/6] asm/sections: Add COMPARE_SECTIONS macro Nathan Chancellor
2020-02-19 4:54 ` [PATCH 2/6] kernel/extable: Wrap section comparison in sort_main_extable with COMPARE_SECTIONS Nathan Chancellor
2020-02-19 4:54 ` [PATCH 3/6] tracing: Wrap section comparison in tracer_alloc_buffers " Nathan Chancellor
2020-02-19 14:34 ` Steven Rostedt
2020-02-19 17:44 ` Nick Desaulniers
2020-02-19 18:16 ` Jason Gunthorpe
2020-02-19 19:09 ` Steven Rostedt
2020-02-19 19:11 ` Nick Desaulniers
2020-02-19 19:22 ` Nathan Chancellor
2020-02-19 19:43 ` Steven Rostedt [this message]
2020-02-19 19:54 ` Jason Gunthorpe
2020-02-19 21:32 ` Nick Desaulniers
2020-02-19 4:54 ` [PATCH 4/6] dynamic_debug: Wrap section comparison in dynamic_debug_init " Nathan Chancellor
2020-02-19 4:54 ` [PATCH 5/6] mm: kmemleak: Wrap section comparison in kmemleak_init " Nathan Chancellor
2020-02-19 4:54 ` [PATCH 6/6] kbuild: Enable -Wtautological-compare Nathan Chancellor
2020-04-21 4:03 ` [PATCH 0/6] Silence some instances of -Wtautological-compare and enable globally Andrew Morton
2020-04-21 4:32 ` Nathan Chancellor
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