Messages in this thread | | | Date | Mon, 26 Jul 2010 11:40:44 -0500 (CDT) | From | Christoph Lameter <> | Subject | Re: [PATCH] Tight check of pfn_valid on sparsemem - v4 |
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On Tue, 27 Jul 2010, Minchan Kim wrote:
> This patch registers address of mem_section to memmap itself's page struct's > pg->private field. This means the page is used for memmap of the section. > Otherwise, the page is used for other purpose and memmap has a hole.
What if page->private just happens to be the value of the page struct? Even if that is not possible today, someday someone may add new functionality to the kernel where page->pivage == page is used for some reason.
Checking for PG_reserved wont work?
> +void mark_valid_memmap(unsigned long start, unsigned long end); > + > +#ifdef CONFIG_ARCH_HAS_HOLES_MEMORYMODEL > +static inline int memmap_valid(unsigned long pfn) > +{ > + struct page *page = pfn_to_page(pfn); > + struct page *__pg = virt_to_page(page); > + return page_private(__pg) == (unsigned long)__pg;
Hmmm.. hmmm....
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