On Mon 29-07-13 17:20:01, Peter Zijlstra wrote: > On Mon, Jul 29, 2013 at 04:53:08PM +0200, Michal Hocko wrote: > > Peter, for you context the lockdep splat has been reported > > here: https://lkml.org/lkml/2013/7/17/381 > > > > Minchan has proposed to workaround it by using SINGLE_DEPTH_NESTING > > https://lkml.org/lkml/2013/7/23/812 > > > > my idea was to use a separate class key for hugetlb as it is quite > > special in many ways: > > https://lkml.org/lkml/2013/7/25/277 > > > > What is the preferred way of fixing such an issue? > > The class is the safer annotation. OK, I will use the class then. It should prevent other false positives AFAIU. > That said; it is a rather horrible issue any which way. This PMD sharing > is very unique to hugetlbfs (also is that really worth the effort these > days?) and it will make it impossible to make hugetlbfs swappable. No idea. > The other solution is to make the pmd allocation GFP_NOFS. That would be just papering over the lockdep limitation. So I would rather stick with something lockdep specific. I will cook up a patch. Thanks! -- Michal Hocko SUSE Labs -- 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>