LKML Archive on lore.kernel.org
 help / color / Atom feed
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
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

  reply index

Thread overview: 23+ 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
2019-04-06 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

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=714a38fe-a733-7264-bb06-d94bd58a245a@metux.net \
    --to=lkml@metux.net \
    --cc=Gilles.Muller@lip6.fr \
    --cc=Markus.Elfring@web.de \
    --cc=andriy.shevchenko@linux.intel.com \
    --cc=bgolaszewski@baylibre.com \
    --cc=cocci@systeme.lip6.fr \
    --cc=gregkh@linuxfoundation.org \
    --cc=himanshujha199640@gmail.com \
    --cc=kernel-janitors@vger.kernel.org \
    --cc=linus.walleij@linaro.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=michal.lkml@markovi.net \
    --cc=nicolas.palix@imag.fr \
    --cc=rafael@kernel.org \
    --cc=yamada.masahiro@socionext.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

LKML Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/lkml/0 lkml/git/0.git
	git clone --mirror https://lore.kernel.org/lkml/1 lkml/git/1.git
	git clone --mirror https://lore.kernel.org/lkml/2 lkml/git/2.git
	git clone --mirror https://lore.kernel.org/lkml/3 lkml/git/3.git
	git clone --mirror https://lore.kernel.org/lkml/4 lkml/git/4.git
	git clone --mirror https://lore.kernel.org/lkml/5 lkml/git/5.git
	git clone --mirror https://lore.kernel.org/lkml/6 lkml/git/6.git
	git clone --mirror https://lore.kernel.org/lkml/7 lkml/git/7.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 lkml lkml/ https://lore.kernel.org/lkml \
		linux-kernel@vger.kernel.org linux-kernel@archiver.kernel.org
	public-inbox-index lkml


Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-kernel


AGPL code for this site: git clone https://public-inbox.org/ public-inbox