From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Wu Fengguang <fengguang.wu@intel.com>
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
Date: Thu, 18 Nov 2010 17:29:00 +0100 [thread overview]
Message-ID: <1290097740.2109.1527.camel@laptop> (raw)
In-Reply-To: <20101118160652.GA19459@localhost>
On Fri, 2010-11-19 at 00:06 +0800, Wu Fengguang wrote:
> 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?
it could, but we chose not to implement the symbol it emits for these
things so as to cause pain.. that was still assuming the world of 32bit
computing was relevant and 64bit divides were expensive ;-)
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next prev parent reply other threads:[~2010-11-18 16:29 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-18 6:57 [PATCH] writeback: prevent bandwidth calculation overflow Wu Fengguang
2010-11-18 14:27 ` Rik van Riel
2010-11-18 15:44 ` Wu Fengguang
2010-11-18 16:02 ` Peter Zijlstra
2010-11-18 16:06 ` Wu Fengguang
2010-11-18 16:22 ` Wu Fengguang
2010-11-18 16:36 ` Wu Fengguang
2010-11-18 16:29 ` Peter Zijlstra [this message]
2010-11-18 16:34 ` Wu Fengguang
2010-11-18 16:13 ` Wu Fengguang
2010-11-19 16:06 ` Michal Hocko
2010-11-19 18:44 ` Wu Fengguang
2010-11-22 9:54 ` Michal Hocko
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