From: Stefani Seibold <stefani@seibold.net>
To: Richard Yang <weiyang@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Stephen Rothwell <sfr@canb.auug.org.au>,
linux-next@vger.kernel.org, linux-kernel@vger.kernel.org,
richard -rw- weinberger <richard.weinberger@gmail.com>,
Jiri Kosina <jkosina@suse.cz>
Subject: Re: linux-next: build warnings after merge of the akpm tree
Date: Fri, 26 Oct 2012 07:44:51 +0200 [thread overview]
Message-ID: <1351230291.12511.7.camel@wall-e> (raw)
In-Reply-To: <20121025223656.GA3805@richard.(null)>
Am Freitag, den 26.10.2012, 06:36 +0800 schrieb Richard Yang:
> >
> >And holy cow that code is hard to read :( Why was kfifo_in()
> >implemented as a macro, anyway? AFAICT all its args have a known type,
> >so we could have used a proper C interface, which would have fixed all
> >this nicely.
>
Thats simple for performance reasons, the compiler remove most of the
code during the compile stage, so no runtime checks are necessary. And
it is the only way since C does not provides templates like C++.
> Hmm, move the definition of kfifo_in()/kfifo_out() into the kfifo.c?
>
Don't do it. this will result in a performance degradation. Look at the
disassembled code by each change in code and compare it with the
previous one. I don't believe that you can produce better code.
next prev parent reply other threads:[~2012-10-26 5:45 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-25 3:28 linux-next: build warnings after merge of the akpm tree Stephen Rothwell
2012-10-25 3:30 ` Stephen Rothwell
[not found] ` <20121025141232.GB4730@richard.(null)>
2012-10-25 14:16 ` Stephen Rothwell
[not found] ` <508948de.01dc440a.58ed.ffffff17SMTPIN_ADDED@mx.google.com>
2012-10-25 22:23 ` Andrew Morton
2012-10-25 23:50 ` Stephen Rothwell
[not found] ` <20121025223656.GA3805@richard.(null)>
2012-10-26 5:44 ` Stefani Seibold [this message]
[not found] ` <20121025130952.GA4730@richard.(null)>
2012-10-25 14:20 ` Stephen Rothwell
-- strict thread matches above, loose matches on Subject: below --
2012-11-29 6:19 Stephen Rothwell
2012-11-29 7:24 ` Lars Ellenberg
2016-11-24 5:20 Stephen Rothwell
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