Messages in this thread | | | Date | Thu, 23 Apr 2009 16:06:10 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH 19/22] Update NR_FREE_PAGES only as necessary |
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On Wed, 22 Apr 2009 14:53:24 +0100 Mel Gorman <mel@csn.ul.ie> wrote:
> When pages are being freed to the buddy allocator, the zone > NR_FREE_PAGES counter must be updated. In the case of bulk per-cpu page > freeing, it's updated once per page. This retouches cache lines more > than necessary. Update the counters one per per-cpu bulk free. > > ... > > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -460,7 +460,6 @@ static inline void __free_one_page(struct page *page, > int migratetype) > { > unsigned long page_idx; > - int order_size = 1 << order; > > if (unlikely(PageCompound(page))) > if (unlikely(destroy_compound_page(page, order))) > @@ -470,10 +469,9 @@ static inline void __free_one_page(struct page *page, > > page_idx = page_to_pfn(page) & ((1 << MAX_ORDER) - 1); > > - VM_BUG_ON(page_idx & (order_size - 1)); > + VM_BUG_ON(page_idx & ((1 << order) - 1)); > VM_BUG_ON(bad_range(zone, page)); >
<head spins>
Is this all a slow and obscure way of doing
VM_BUG_ON(order > MAX_ORDER);
?
If not, what _is_ it asserting?
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