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@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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