On Tue, Mar 23, 2010 at 12:11:01PM -0500, Christoph Lameter wrote: > No it does not happen on the fly. It happens only when you can account for > all references that current exist for the page to be migrated. Then you > change all the references at once. The mechanism ensures that there is no > one else operating on the page. And if one of the references is taken by GUP migration fails and you can try later or wait for I/O. This is not the case for split_huge_page, we don't fail or wait there. -- 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>