Qestion about page->_count and page reclaim

[Jimmy Pan]

correct me if i am wrong
i presume that page pertains to a physical page
when the page is allocated, _count would be 1. every process that wants to
obtain the page might solicit it from page cache first, if exsists, then
_count would increment by one.
every process would try to put_page as it releases the page or exits
On Feb 5, 2013 4:37 PM, "Li Haifeng" <omycle at gmail.com> wrote:

> Hi, all in kernel.
>
> The page->_count is the page frame's usage count. When page is
> allocated, the page->_cout will be set 1.
>
> After be allocated from buddy system, the page will be used by
> process.  get_page and put_page/put_page_testzero will used in pairs.
> is it right?
>
> When the page is reclaimed to buddy system, the page->_count should be
> 0. However, Because the initialization of page->_count is 1,
> get_page() and put_page() is called in pairs, I coufused how
> page->_count will be 0?
>
> Thanks.
>
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