Re: [PATCH 01/17] writeback: remove the internal 5% low bound ondirty_ratio

[Johannes Weiner]

On Sun, Sep 12, 2010 at 11:49:46PM +0800, Wu Fengguang wrote:
> The dirty_ratio was siliently limited in global_dirty_limits() to >= 5%.
> This is not a user expected behavior. And it's inconsistent with
> calc_period_shift(), which uses the plain vm_dirty_ratio value.
> 
> Let's rip the arbitrary internal bound. It may impact some very weird
> user space applications. However we are going to dynamicly sizing the
> dirty limits anyway, which may well break such applications, too.
> 
> At the same time, fix balance_dirty_pages() to work with the
> dirty_thresh=0 case. This allows applications to proceed when
> dirty+writeback pages are all cleaned.
> 
> And ">" fits with the name "exceeded" better than ">=" does. Neil
> think it is an aesthetic improvement as well as a functional one :)
> 
> CC: Jan Kara <jack@xxxxxxx>
> Proposed-by: Con Kolivas <kernel@xxxxxxxxxxx>
> Acked-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
> Reviewed-by: Rik van Riel <riel@xxxxxxxxxx>
> Reviewed-by: Neil Brown <neilb@xxxxxxx>
> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
> Signed-off-by: Wu Fengguang <fengguang.wu@xxxxxxxxx>

Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
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