Messages in this thread | | | Date | Fri, 20 Jul 2007 07:59:53 +0800 | From | "Fengwei Yin" <> | Subject | Re: About get_page for compound page |
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On 7/20/07, Peter Zijlstra <peterz@infradead.org> wrote: > On Thu, 2007-07-19 at 23:54 +0800, Fengwei Yin wrote: > > Hi, > > In get_page(), the parameter page is changed by > > page = compound_head(page); > > if the page is not the first page of compound pages. > > > > My question: is this behavior correct? > > Yes it is, in general the page state of a compound page is kept in the > first page of the set. > Yes. I know this. But static inline void get_page(struct page *page) ~~~~~~ changed by this function. { page = compound_head(page); ~~~~~~~~~~~~~~~~~~~~~~~ VM_BUG_ON(atomic_read(&page->_count) == 0); atomic_inc(&page->_count); }
As I understand, just need update the first page reference count. Or the caller aware of this bahavior?
Or change it to static inline void get_page(struct page *page) { struct page *head_page = compound_head(page); VM_BUG_ON(atomic_read(&head_page->_count) == 0); atomic_inc(&head_page->_count); }
Regards Yin, Fengwei - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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