On Tue, Dec 20, 2011 at 02:38:38AM +0800, Naoya Horiguchi wrote: > This flag shows that a given pages is a subpage of transparent hugepage. > It does not care about whether it is a head page or a tail page, because > it's clear from pfn of the target page which you should know when you read > /proc/kpageflags. OK, this is aligning with KPF_HUGE. For those who only care about head/tail pages, will the KPF_COMPOUND_HEAD/KPF_COMPOUND_TAIL flags be set automatically for thp? Which may be more convenient to test/filter than the page address. > Signed-off-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx> Reviewed-by: Wu Fengguang <fengguang.wu@xxxxxxxxx> As you already discussed, the below #ifdef should be removed. In fact, kernel-page-flags.h is intended for direct inclusion by user space tools, so must not have any conditional defines. > --- 3.2-rc5.orig/include/linux/kernel-page-flags.h > +++ 3.2-rc5/include/linux/kernel-page-flags.h > @@ -31,6 +31,10 @@ > > #define KPF_KSM 21 > > +#ifdef CONFIG_TRANSPARENT_HUGEPAGE > +#define KPF_THP 22 > +#endif > + > /* kernel hacking assistances > * WARNING: subject to change, never rely on them! > */ > -- > 1.7.7.3 -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>