On Wed, Sep 26, 2012 at 12:02:34AM -0400, Naoya Horiguchi wrote: ... > > > + * page is a thp, not a non-huge compound page. > > > + */ > > > + else if (PageTransCompound(page) && !PageSlab(page)) > > > u |= 1 << KPF_THP; > > > > Good catch! > > > > Will this report THP for the various drivers that do __GFP_COMP > > page allocations? > > I'm afraid it will. I think of checking PageLRU as an alternative, > but it needs compound_head() to report tail pages correctly. > In this context, pages are not pinned or locked, so it's unsafe to > use compound_head() because it can return a dangling pointer. > Maybe it's a thp's/hugetlbfs's (not kpageflags specific) problem, > so going forward with compound_head() expecting that it will be > fixed in the future work can be an option. It seems that compound_trans_head() solves this problem, so I'll simply use it. Naoya -- 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>