On Mon, 27 May 2013 14:02:58 +0100 Mel Gorman <mgorman@xxxxxxx> wrote: > Page reclaim keeps track of dirty and under writeback pages and uses it to > determine if wait_iff_congested() should stall or if kswapd should begin > writing back pages. This fails to account for buffer pages that can be under > writeback but not PageWriteback which is the case for filesystems like ext3 > ordered mode. Furthermore, PageDirty buffer pages can have all the buffers > clean and writepage does no IO so it should not be accounted as congested. iirc, the PageDirty-all-buffers-clean state is pretty rare. It might not be worth bothering about? > This patch adds an address_space operation that filesystems may > optionally use to check if a page is really dirty or really under > writeback. address_space_operations methods are Documented in Documentation/filesystems/vfs.txt ;) > An implementation is provided for for buffer_heads is added > and used for block operations and ext3 in ordered mode. By default the > page flags are obeyed. > > Credit goes to Jan Kara for identifying that the page flags alone are > not sufficient for ext3 and sanity checking a number of ideas on how > the problem could be addressed. -- 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>