On Fri, Aug 13, 2010 at 07:47:21AM -0500, Christoph Lameter wrote: > On Thu, 12 Aug 2010, Naoya Horiguchi wrote: > > > > Can you also avoid refcounts being increased during migration? > > > > Yes. I think this will be done in above-mentioned refactoring. > > Thats not what I meant. Can you avoid other processors increasing > refcounts (direct I/O etc?) on any page struct of the huge page while > migration is running? In my understanding, in current code "other processors increasing refcount during migration" can happen both in non-hugepage direct I/O and in hugepage direct I/O in the similar way (i.e. get_user_pages_fast() from dio_refill_pages()). So I think there is no specific problem to hugepage. Or am I missing your point? > > > This patch only handles migration under direct I/O. > > For the opposite (direct I/O under migration) it's not true. > > I wrote additional patches (later I'll reply to this email) > > for solving locking problem. Could you review them? > > Sure. > > > (Maybe these patches are beyond the scope of hugepage migration patch, > > so is it better to propose them separately?) > > Migration with known races is really not what we want in the kernel. Yes. Thanks, Naoya Horiguchi -- 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>