| Subject | Re: [PATCH 3/5] writeback: dirty rate control | From | Peter Zijlstra <> | Date | Tue, 09 Aug 2011 19:02:02 +0200 |
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On Sat, 2011-08-06 at 16:44 +0800, Wu Fengguang wrote:
> + pos_bw = bw * pos_ratio >> BANDWIDTH_CALC_SHIFT; > + pos_bw++; /* this avoids bdi->dirty_ratelimit get stuck in 0 */ > +
> + pos_ratio *= bdi->avg_write_bandwidth; > + do_div(pos_ratio, dirty_bw | 1); > + ref_bw = bw * pos_ratio >> BANDWIDTH_CALC_SHIFT;
when written out that results in:
bw * pos_ratio * bdi->avg_write_bandwidth ref_bw = ----------------------------------------- dirty_bw
which would suggest you write it like:
ref_bw = div_u64((u64)pos_bw * bdi->avg_write_bandwidth, dirty_bw | 1);
since pos_bw is already bw * pos_ratio per the above.
Or am I missing something?
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