Messages in this thread | | | Date | Tue, 27 Jul 2010 22:55:25 +0800 | From | Wu Fengguang <> | Subject | Re: [PATCH 8/8] vmscan: Kick flusher threads to clean pages when reclaim is encountering dirty pages |
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On Tue, Jul 27, 2010 at 10:40:26PM +0800, Mel Gorman wrote: > On Tue, Jul 27, 2010 at 10:34:23PM +0800, Wu Fengguang wrote: > > > If you plan to keep wakeup_flusher_threads(), a simpler form may be > > > sufficient, eg. > > > > > > laptop_mode ? 0 : (nr_dirty * 16) > > > > This number is not sensitive because the writeback code may well round > > it up to some more IO efficient value (currently 4MB). AFAIK the > > nr_pages parameters passed by all existing flusher callers are some > > rule-of-thumb value, and far from being an exact number. > > > > I get that it's a rule of thumb but decided I would still pass in some value > related to nr_dirty that was bounded in some manner. > Currently, that bound is 4MB but maybe it should have been bound to > MAX_WRITEBACK_PAGES (which is 4MB for x86, but could be anything > depending on the base page size).
I see your worry about much bigger page size making
vmscan batch size > writeback batch size
and it's a legitimate worry.
Thanks, Fengguang
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