On Mon, Jul 23, 2012 at 11:33:32AM +0900, Minchan Kim wrote: > Look at memory-hotplug, offline_page calls has_unmovable_pages, scan_lru_pages > and do_migrate_range which calls isolate_lru_page. They consider only LRU pages > to migratable ones. > As promised, I looked into those bits. Yes, they only isolate LRU pages, and as such, having this series merged or not doesn't change a bit for that code path. In fact, having this series merged and teaching hotplug's offline_pages()/do_migrate_rage() about ballooned pages might be extremely beneficial in the rare event offlining memory stumbles across a balloon page. As Rik said, I believe this is something we can look into in the near future. > IMHO, better approach is that after we can get complete free pageblocks > by compaction or reclaim, move balloon pages into that pageblocks and make > that blocks to unmovable. It can prevent fragmentation and it makes > current or future code don't need to consider balloon page. > I totally agree with Rik on this one, as well. This is the wrong approach here. All that said, I'll soon respin a v5 based on your comments on branch hinting and commentary improvements, as well as addressing AKPM's concerns. I'll also revert isolate_balloon_page() last changes back to make it a public symbol again, as (I believe) we'll shortly be using it for letting hotplug bits aware of how to isolate ballooned pages. -- 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>