Re: [PATCH] Tight check of pfn_valid on sparsemem - v4

From: Minchan Kim
Date: Tue Jul 27 2010 - 18:33:15 EST

On Tue, Jul 27, 2010 at 11:34 PM, Christoph Lameter
<cl@xxxxxxxxxxxxxxxxxxxx> wrote:
> On Tue, 27 Jul 2010, Minchan Kim wrote:
>> But in fact I have a concern to use PG_reserved since it can be used
>> afterward pfn_valid normally to check hole in non-hole system. So I
>> think it's redundant.

Ignore me. I got confused.

> PG_reserved is already used to mark pages not handled by the page
> allocator (see mmap_init_zone).

I will resend below approach.

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) == MAGIC_MEMMAP && PageReserved(__pg);

Thanks, all.

Kind regards,
Minchan Kim
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