Messages in this thread | | | Date | Mon, 16 Mar 2009 16:47:36 +0000 | From | Mel Gorman <> | Subject | Re: [PATCH 26/35] Use the per-cpu allocator for orders up to PAGE_ALLOC_COSTLY_ORDER |
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On Mon, Mar 16, 2009 at 12:26:07PM -0400, Christoph Lameter wrote: > On Mon, 16 Mar 2009, Mel Gorman wrote: > > > -static void free_hot_cold_page(struct page *page, int cold) > > +static void free_hot_cold_page(struct page *page, int order, int cold) > > { > > struct zone *zone = page_zone(page); > > struct per_cpu_pages *pcp; > > unsigned long flags; > > int clearMlocked = PageMlocked(page); > > > > + /* SLUB can return lowish-order compound pages that need handling */ > > + if (order > 0 && unlikely(PageCompound(page))) > > + if (unlikely(destroy_compound_page(page, order))) > > + return; > > + > > Isnt that also true for stacks and generic network objects ==- 8k? >
I think they are vanilla high-order pages, not compound pages.
> > again: > > cpu = get_cpu(); > > - if (likely(order == 0)) { > > + if (likely(order <= PAGE_ALLOC_COSTLY_ORDER)) { > > struct per_cpu_pages *pcp; > > + int batch; > > + int delta; > > > > pcp = &zone_pcp(zone, cpu)->pcp; > > + batch = max(1, pcp->batch >> order); > > local_irq_save(flags); > > if (!pcp->count) { > > - pcp->count = rmqueue_bulk(zone, 0, > > - pcp->batch, &pcp->list, migratetype); > > + delta = rmqueue_bulk(zone, order, batch, > > + &pcp->list, migratetype); > > + bulk_add_pcp_page(pcp, order, delta); > > if (unlikely(!pcp->count)) > > goto failed; > > The pcp adds a series of order N pages if an order N alloc occurs and the > queue is empty? >
Nope, that would be bad. The calculation of batch is made above and is
batch = max(1, pcp->batch >> order);
so order is taken into account when deciding how many pages to allocate.
-- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab
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