On Tue, 19 Feb 2013, Ric Mason wrote: > > There is a call of try_to_free_swap in function swap_writepage, if > swap_writepage is call from shrink_page_list path, PageSwapCache(page) == > trure, PageWriteback(page) maybe false, page_swapcount(page) == 0, then will > delete the page from swap cache and free swap slot, where I miss? That's correct. PageWriteback is sure to be false there. page_swapcount usually won't be 0 there, but sometimes it will be, and in that case we do want to delete from swap cache and free the swap slot. Hugh -- 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>