Re: [patch] SLQB slab allocator (try 2)

From: Mel Gorman
Date: Tue Feb 03 2009 - 07:01:58 EST


On Tue, Feb 03, 2009 at 10:50:54PM +1100, Nick Piggin wrote:
> On Tuesday 03 February 2009 22:28:52 Mel Gorman wrote:
> > On Tue, Feb 03, 2009 at 09:36:24PM +1100, Nick Piggin wrote:
>
> > > I'd be interested to see how slub performs if booted with
> > > slub_min_objects=1 (which should give similar order pages to SLAB and
> > > SLQB).
> >
> > Just to clarify on this last point, do you mean slub_max_order=0 to
> > force order-0 allocations in SLUB?
>
> Hmm... I think slub_min_objects=1 should also do basically the same.
> Actually slub_min_object=1 and slub_max_order=1 should get closest I
> think.
>

I'm going with slub_min_objects=1 and slub_max_order=0. A quick glance
of the source shows the calculation as

for (order = max(min_order,
fls(min_objects * size - 1) - PAGE_SHIFT);
order <= max_order; order++) {

so the max_order is inclusive not exclusive. This will force the order-0
allocations I think you are looking for.

--
Mel Gorman
Part-time Phd Student Linux Technology Center
University of Limerick IBM Dublin Software Lab
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