From: "Enrico Weigelt, metux IT consult" <lkml@metux.net>
To: Markus Elfring <Markus.Elfring@web.de>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Bartosz Golaszewski <bgolaszewski@baylibre.com>
Cc: cocci@systeme.lip6.fr, kernel-janitors@vger.kernel.org,
linux-kernel@vger.kernel.org,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Gilles Muller <Gilles.Muller@lip6.fr>,
Himanshu Jha <himanshujha199640@gmail.com>,
Linus Walleij <linus.walleij@linaro.org>,
Masahiro Yamada <yamada.masahiro@socionext.com>,
Michal Marek <michal.lkml@markovi.net>,
Nicolas Palix <nicolas.palix@imag.fr>
Subject: Re: drivers: Inline code in devm_platform_ioremap_resource() from two functions
Date: Tue, 18 Jun 2019 11:35:34 +0200 [thread overview]
Message-ID: <714a38fe-a733-7264-bb06-d94bd58a245a@metux.net> (raw)
In-Reply-To: <efc38197-f846-142d-fbaf-93327c2669c9@web.de>
On 18.06.19 07:37, Markus Elfring wrote:
>>> Two function calls were combined in this function implementation.
>>> Inline corresponding code so that extra error checks can be avoided here.
>>
>> What exactly is the purpose of this ?
>
> I suggest to take another look at the need and relevance of involved
> error checks in the discussed function combination.
Sorry, don't have the time for guessing and trying to reproduce your
thoughts. That's why we have patch descriptions / commit messages.
It would be a lot easier for all of us if you just desribe the exact
problem you'd like to solve and your approach to do so.
>> Looks like a notable code duplication ...
>
> This can be.
I doubt that code duplication is appreciated, as this increases the
maintenance overhead. (actually, we're usually trying to reduce that,
eg. by using lots of generic helpers).
>> I thought we usually try to reduce this, instead of introducing new ones.
>
> Would you like to check the software circumstances once more
> for the generation of a similar code structure by a C compiler
> (or optimiser)?
As said: unfortunately, I don't have the time to do that - you'd have to
tell us, what exactly you've got in mind.
If it's just about some error checks which happen to be redundant in a
particular case, you'll have to show that this case is a *really* hot
path (eg. irq, syscall, scheduling, etc) - but I don't see that here.
What's the exact scenario you're trying to optimize ? Any actual
measurements on how your patch improves that ?
Look, I understand that you'd like to squeeze out maximum performance,
but this has to be practically maintainable. I could list a lot of
things that I don't need in particular use cases and would like to
introduce build knobs for, but I have to understand that maintainers
have to be pretty reluctant towards those things.
--mtx
--
Enrico Weigelt, metux IT consult
Free software and Linux embedded engineering
info@metux.net -- +49-151-27565287
next prev parent reply other threads:[~2019-06-18 9:35 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-06 6:11 [PATCH] coccinelle: api: add devm_platform_ioremap_resource script Himanshu Jha
2019-04-06 6:31 ` Julia Lawall
2019-04-06 6:34 ` Julia Lawall
2019-07-06 12:16 ` [Cocci] " Masahiro Yamada
2019-07-06 13:39 ` Julia Lawall
2019-07-07 9:55 ` Coccinelle: " Markus Elfring
2019-07-07 12:38 ` Masahiro Yamada
2019-09-19 7:21 ` Markus Elfring
2019-04-06 12:36 ` [PATCH] coccinelle: " Markus Elfring
2019-06-08 15:24 ` Coccinelle: " Markus Elfring
2019-06-08 17:26 ` Julia Lawall
2019-06-09 8:55 ` Markus Elfring
2019-06-11 20:40 ` Enrico Weigelt, metux IT consult
2019-06-12 5:28 ` Julia Lawall
2019-06-12 6:24 ` Markus Elfring
2019-06-14 9:22 ` [PATCH] drivers: Inline code in devm_platform_ioremap_resource() from two functions Markus Elfring
2019-06-14 9:27 ` [Cocci] " Julia Lawall
2019-06-15 11:00 ` Markus Elfring
2019-06-14 10:07 ` [PATCH] " Greg Kroah-Hartman
2019-06-17 20:21 ` Enrico Weigelt, metux IT consult
2019-06-18 5:37 ` Markus Elfring
2019-06-18 9:35 ` Enrico Weigelt, metux IT consult [this message]
2019-06-18 10:21 ` Dan Carpenter
2019-06-18 11:44 ` Markus Elfring
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