On Sat 31-07-10 11:33:22, Mel Gorman wrote: > On Fri, Jul 30, 2010 at 03:06:01PM -0700, Andrew Morton wrote: > > Sigh. We have sooo many problems with writeback and latency. Read > > https://bugzilla.kernel.org/show_bug.cgi?id=12309 and weep. > > You aren't joking. > > > Everyone's > > running away from the issue and here we are adding code to solve some > > alleged stack-overflow problem which seems to be largely a non-problem, > > by making changes which may worsen our real problems. > > > > As it is, filesystems are beginnning to ignore writeback from direct > reclaim - such as xfs and btrfs. I'm lead to believe that ext3 > effectively ignores writeback from direct reclaim although I don't have > access to code at the moment to double check (am on the road). So either > way, we are going to be facing this problem so the VM might as well be > aware of it :/ Umm, ext3 should be handling direct reclaim just fine. ext4 does however ignore it when a page does not have block already allocated (which is a common case with delayed allocation). Honza -- Jan Kara <jack@xxxxxxx> SUSE Labs, CR -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>