From: Andi Kleen <andi@firstfloor.org>
To: Dave Jones <davej@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Josh Triplett <josh@freedesktop.org>,
linux-sparse@vger.kernel.org, linux-kernel@vger.kernel.org,
Al Viro <viro@ftp.linux.org.uk>
Subject: Re: sparse -Wptr-subtraction-blows: still needed?
Date: 02 May 2007 15:03:59 +0200 [thread overview]
Message-ID: <p73abwnxtq8.fsf@bingen.suse.de> (raw)
In-Reply-To: <20070502024242.GC6935@redhat.com>
Dave Jones <davej@redhat.com> writes:
>
> #define __page_to_pfn(page) ((unsigned long)((page) - mem_map) + \
> ARCH_PFN_OFFSET)
>
> looks like the other two variants of __page_to_pfn also use similar arithmatic.
No way around this. The only way to turn a page into a pfn is to do
a constant division. Should be fairly cheap here though.
-Andi (who thinks the sparse warning is dumb; better to look at oprofiles
of hot paths)
prev parent reply other threads:[~2007-05-02 12:06 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-05-01 21:08 sparse -Wptr-subtraction-blows: still needed? Josh Triplett
2007-05-01 21:43 ` Linus Torvalds
2007-05-01 23:59 ` Josh Triplett
2007-05-02 0:24 ` Linus Torvalds
2007-05-02 0:35 ` Al Viro
2007-05-02 12:02 ` Alan Cox
2007-05-02 13:19 ` Andi Kleen
2007-05-02 0:26 ` Al Viro
2007-05-02 0:02 ` Al Viro
2007-05-02 2:42 ` Dave Jones
2007-05-02 13:03 ` Andi Kleen [this message]
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