On Fri, Feb 19, 2010 at 09:12:44AM +0900, KAMEZAWA Hiroyuki wrote: > On Thu, 18 Feb 2010 18:02:31 +0000 > Mel Gorman <mel@xxxxxxxxx> wrote: > > > rmap_walk_anon() does not use page_lock_anon_vma() for looking up and > > locking an anon_vma and it does not appear to have sufficient locking to > > ensure the anon_vma does not disappear from under it. > > > > This patch copies an approach used by KSM to take a reference on the > > anon_vma while pages are being migrated. This should prevent rmap_walk() > > running into nasty surprises later because anon_vma has been freed. > > > > Signed-off-by: Mel Gorman <mel@xxxxxxxxx> > > I have no objection to this direction. But after this patch, you can remove > rcu_read_lock()/unlock() in unmap_and_move(). > ruc_read_lock() is for guarding against anon_vma replacement. > Thanks. I expected that would be the case but was going to leave at least one kernel release between when compaction went in and I did that. -- 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>