Messages in this thread | | | Date | Mon, 22 Nov 2010 00:25:56 +0900 | From | Minchan Kim <> | Subject | Re: [PATCH 3/4] alloc_contig_pages() allocate big chunk memory using migration |
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On Fri, Nov 19, 2010 at 05:15:28PM +0900, KAMEZAWA Hiroyuki wrote: > From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> > > Add an function to allocate contiguous memory larger than MAX_ORDER. > The main difference between usual page allocator is that this uses > memory offline technique (Isolate pages and migrate remaining pages.). > > I think this is not 100% solution because we can't avoid fragmentation, > but we have kernelcore= boot option and can create MOVABLE zone. That > helps us to allow allocate a contiguous range on demand. > > The new function is > > alloc_contig_pages(base, end, nr_pages, alignment) > > This function will allocate contiguous pages of nr_pages from the range > [base, end). If [base, end) is bigger than nr_pages, some pfn which > meats alignment will be allocated. If alignment is smaller than MAX_ORDER, > it will be raised to be MAX_ORDER. > > __alloc_contig_pages() has much more arguments. > > > Some drivers allocates contig pages by bootmem or hiding some memory > from the kernel at boot. But if contig pages are necessary only in some > situation, kernelcore= boot option and using page migration is a choice. > > Changelog: 2010-11-19 > - removed no_search > - removed some drain_ functions because they are heavy. > - check -ENOMEM case > > Changelog: 2010-10-26 > - support gfp_t > - support zonelist/nodemask > - support [base, end) > - support alignment > > Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Minchan Kim <minchan.kim@gmail.com>
Trivial comment below.
> +EXPORT_SYMBOL_GPL(alloc_contig_pages); > + > +struct page *alloc_contig_pages_host(unsigned long nr_pages, int align_order) > +{ > + return __alloc_contig_pages(0, max_pfn, nr_pages, align_order, -1, > + GFP_KERNEL | __GFP_MOVABLE, NULL); > +}
We need include #include <linux/bootmem.h> for using max_pfn.
-- Kind regards, Minchan Kim
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