On Mon, Jul 19, 2010 at 10:19:34AM -0400, Christoph Hellwig wrote: > On Mon, Jul 19, 2010 at 02:11:26PM +0100, Mel Gorman wrote: > > As the call-chain for writing anonymous pages is not expected to be deep > > and they are not cleaned by flusher threads, anonymous pages are still > > written back in direct reclaim. > > While it is not quite as deep as it skips the filesystem allocator and > extent mapping code it can still be quite deep for swap given that it > still has to traverse the whole I/O stack. Probably not worth worrying > about now, but we need to keep an eye on it. > Agreed that we need to keep an eye on it. If this ever becomes a problem, we're going to need to consider a flusher for anonymous pages. If you look at the figures, we are still doing a lot of writeback of anonymous pages. Granted, the layout of swap sucks anyway but it's something to keep at the back of the mind. > The patch looks fine to me anyway. > Thanks. -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab -- 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>