On Mon 16-05-16 21:42:23, Wang Xiaoqiang wrote: > Hi all, > > I am really confused about these two functions. The following code snippet: > > if(unlikely(atomic_read(&page->_mapcount) != -1)) > bad_reason ="nonzero mapcount";if(unlikely(page->mapping != NULL)) > bad_reason ="non-NULL mapping";if(unlikely(page_ref_count(page) !=0)) > bad_reason ="nonzero _count"; > ... > Wouldn't the previous value of "bad_reason" be overwritten by > the later? Hope to receive from you. yes it would. Why that would matter. The checks should be in an order which could give us a more specific reason with later checks. bad_page() will then print more detailed information. -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>