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Date: Fri, 19 Nov 2010 00:06:52 +0800
From: Wu Fengguang <fengguang.wu@intel.com>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Rik van Riel <riel@redhat.com>, Andrew Morton <akpm@linux-foundation.org>,
        Jan Kara <jack@suse.cz>, "Li, Shaohua" <shaohua.li@intel.com>,
        Christoph Hellwig <hch@lst.de>, Dave Chinner <david@fromorbit.com>,
        "Theodore Ts'o" <tytso@mit.edu>, Chris Mason <chris.mason@oracle.com>,
        Mel Gorman <mel@csn.ul.ie>,
        KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
        linux-mm <linux-mm@kvack.org>,
        "linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] writeback: prevent bandwidth calculation overflow
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On Fri, Nov 19, 2010 at 12:02:01AM +0800, Peter Zijlstra wrote:
> On Thu, 2010-11-18 at 23:44 +0800, Wu Fengguang wrote:
> > +               pause = HZ * pages_dirtied / (bw + 1);
> 
> Shouldn't that be using something like div64_u64 ?

OK, but a dumb question: gcc cannot handle this implicitly?

Thanks,
Fengguang