Re: [PATCH v4] kpageflags: fix wrong KPF_THP on non-huge compound pages

2012-09-26 Thread Fengguang Wu
> - else if (PageTransCompound(page)) > + /* > + * PageTransCompound can be true for non-huge compound pages (slab > + * pages or pages allocated by drivers with __GFP_COMP) because it > + * just checks PG_head/PG_tail, so we need to check PageLRU to make > + * sure a gi

Re: [PATCH v4] kpageflags: fix wrong KPF_THP on non-huge compound pages

2012-09-26 Thread David Rientjes
On Wed, 26 Sep 2012, Naoya Horiguchi wrote: > diff --git v3.6-rc6.orig/fs/proc/page.c v3.6-rc6/fs/proc/page.c > index 7fcd0d6..b8730d9 100644 > --- v3.6-rc6.orig/fs/proc/page.c > +++ v3.6-rc6/fs/proc/page.c > @@ -115,7 +115,13 @@ u64 stable_page_flags(struct page *page) > u |= 1 << K

[PATCH v4] kpageflags: fix wrong KPF_THP on non-huge compound pages

2012-09-26 Thread Naoya Horiguchi
KPF_THP can be set on non-huge compound pages (like slab pages or pages allocated by drivers with __GFP_COMP) because PageTransCompound only checks PG_head and PG_tail. Obviously this is a bug and breaks user space applications which look for thp via /proc/kpageflags. This patch rules out setting