Messages in this thread | | | Date | Tue, 11 Aug 2009 09:05:54 -0600 | From | Jonathan Corbet <> | Subject | Re: How to get the address of the page structure from the given virtual address? |
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On Tue, 11 Aug 2009 20:01:41 +0530 "B.Vinai Kumar" <vinaibangala2001@gmail.com> wrote:
> 1) I allocated 8 pages using alloc_pages(GFP_KERNEL, 3). This function > returns the pointer to the first page's page structure. > How can I get the page structure address of the remaining 7 pages?
They will be immediately following the first page structure in the system memory map - they are contiguous pages, after all. So just use pointer arithmetic to find them.
Inquiring minds are indeed curious as to why you need them, though :) > > 2) There is a function page_address() which takes the page structure > as an argument and returns the virtual address of the page > that is pointed by that page structure.
Note that page_address() may not give you a valid address if it's a high-memory page which is not currently mapped.
> Is there any method which > retrives the address of the page structure?
Use virt_to_page() for normal kernel virtual addresses, vmalloc_to_page() for memory in the vmalloc range.
jon
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