Re: meminfo returns inaccurate NR_FILE_PAGES

[Christoph Lameter <clameter@sgi.com>]

On Tue, 17 Apr 2007, Ethan Solomita wrote:

>    Anonymous pages have a value in mapping, but it's not a struct
> address_space, it's a struct vm_area_struct (+1). The NR_FILE_PAGES count is

Wrong. Anonymous pages can be a part of swap space which is an 
address_space.

from include/linux/mm.h

extern struct address_space swapper_space;
static inline struct address_space *page_mapping(struct page *page)
{
        struct address_space *mapping = page->mapping;

        if (unlikely(PageSwapCache(page)))
                mapping = &swapper_space;
        else if (unlikely((unsigned long)mapping & PAGE_MAPPING_ANON))
                mapping = NULL;
        return mapping;
}

> of lines in migrate_page_move_mapping() after modifying *radix_pointer to call
> __dec on the old page and __inc on the new. You can check the zones first if
> you'd like to save effort, although I'm not sure it's a big deal since the
> __dec and __inc functions are only modifying per-cpu accumulation variables.

Ok. That is what the patch does. So please test the patch and get back 
to me.

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