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Re: [Xen-devel] put_page in ptwr_do_page_fault

Hmmm, put_page() release the page, but seems get_page_from_pagenr() does not allocate a page ? Thanks !

On Mon, Oct 15, 2012 at 1:00 AM, Ian Campbell <Ian.Campbell@xxxxxxxxxx> wrote:
On Mon, 2012-10-15 at 07:43 +0100, Xinxin Jin wrote:
> Hi all,
> I am trying to understand write page table handler for PV guests. I
> got the core of ptwr_do_page_fault is x86_emulate() which will emulate
> the write operation in Xen. But why after that Xen calls  put_page()
> to free the page mapped to the PTE ? The code snapshot is as follows:

The put_page balances the get_page inside get_page_from_pagenr which is
in the code you trimmed out below.


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