From: Andi Kleen <andi@firstfloor.org>
To: Namhyung Kim <namhyung@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>,
linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC][PATCH] introduce ptr_diff()
Date: Thu, 19 Aug 2010 14:23:09 +0200 [thread overview]
Message-ID: <87aaoiu6z6.fsf@basil.nowhere.org> (raw)
In-Reply-To: <1282217856-8625-1-git-send-email-namhyung@gmail.com> (Namhyung Kim's message of "Thu, 19 Aug 2010 20:37:36 +0900")
Namhyung Kim <namhyung@gmail.com> writes:
> When I compiled allyesconfig'ed kernel with C=1, I got 1519 lines of
> following message:
>
> include/linux/mm.h:599:16: warning: potentially expensive pointer subtraction
>
> which is around 10% of total warnings. this was caused by page_to_pfn() macro
> so I think it's worth to remove it by calculating pointer subtraction
> manually.
IMHO it would be better to simply disable the warning in sparse instead
of uglying the code just to work around sparse bogosity. It doesnt' seem
to make much sense. A subtraction followed by a shift is not expensive.
-Andi
--
ak@linux.intel.com -- Speaking for myself only.
next prev parent reply other threads:[~2010-08-19 12:23 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-19 11:37 [RFC][PATCH] introduce ptr_diff() Namhyung Kim
2010-08-19 11:57 ` Bernd Petrovitsch
2010-08-19 12:03 ` David Howells
2010-08-19 16:18 ` Måns Rullgård
2010-08-19 12:23 ` Andi Kleen [this message]
2010-08-19 12:40 ` Matthew Wilcox
2010-08-19 12:58 ` Andi Kleen
2010-08-19 12:48 ` Bernd Petrovitsch
2010-08-19 12:59 ` Andi Kleen
2010-08-19 13:05 ` Bernd Petrovitsch
2010-08-19 13:39 ` Andi Kleen
2010-08-20 12:12 ` Al Viro
2010-08-19 15:53 ` Namhyung Kim
2010-08-19 16:04 ` Bernd Petrovitsch
2010-08-19 16:12 ` Namhyung Kim
2010-08-20 12:07 ` Al Viro
2010-08-20 12:49 ` Matthew Wilcox
2010-08-20 12:57 ` Andi Kleen
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