On Mon, Nov 15, 2010 at 09:22:56AM +0000, Mel Gorman wrote: > GFP_LUMPY is something else and is only partially related. Transparent Huge > Pages (THP) does not want to hit lumpy reclaim no matter what the circumstances > are - It is always better for THP to not use lumpy reclaim. It's debatable Agreed. > whether it should even reclaim order-0 pages for compaction so even with > this series, THP might still introduce GFP_LUMPY. reclaim of some order 0 page shouldn't do any significant harm as long as the young bits are not ignored and it's just going "normal" and not aggressive like lumpy. Also we it's ok to do some reclaim as we can free some slab that can't be compacted in case there's excessive amount of slab caches to be shrunk to have a chance to convert unmovable pageblocks to movable ones. And we need at least 2M fully available as migration destination (but I guess that is always available :). In general interleaving compaction with regular-reclaim (no lumpy) before failing allocation sounds ok to me. I guess these days compaction would tend to succeed before lumpy ever gets invoked so the trouble with lumpy would then only trigger when compaction starts failing and we enter reclaim to create more movable pageblocks, but I don't want to risk bad behavior when the amount of anoymous memory goes very high and not all anonymous memory can be backed fully by hugepages. -- 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/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>