On 15.11.19 06:59, lixinhai.lxh@xxxxxxxxx wrote: > On 2019-11-15 at 11:18 Li Xinhai wrote: >> PageAnon() just checking on PAGE_MAPPING_ANON bit would cause page, >> with PageKsm as true, been wrongly considered as PageAnon. Now, >> checking the whole PAGE_MAPPING_FLAGS to avoid this error. >> >> Reported from: >> https://lore.kernel.org/linux-mm/20191113000651.20677-1-rcampbell@xxxxxxxxxx/ >> >> Reported-by: Ralph Campbell <rcampbell@xxxxxxxxxx> >> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> >> Cc: Michal Hocko <mhocko@xxxxxxxx> >> Signed-off-by: Li Xinhai <lixinhai.lxh@xxxxxxxxx> >> --- >> include/linux/page-flags.h | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h >> index 1bf83c8..1849fc3 100644 >> --- a/include/linux/page-flags.h >> +++ b/include/linux/page-flags.h >> @@ -461,7 +461,8 @@ static __always_inline int PageMappingFlags(struct page *page) >> static __always_inline int PageAnon(struct page *page) >> { >> page = compound_head(page); >> - return ((unsigned long)page->mapping & PAGE_MAPPING_ANON) != 0; >> + return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) == >> + PAGE_MAPPING_ANON; >> } >> >> static __always_inline int __PageMovable(struct page *page) >> -- >> 1.8.3.1 >> > > The current semantics of PageAnon() for both KSM and !KSM are used in many > places, so can't change it alone without change other code. > Need skip this patch. ... I assume that was intended because KSM only merges anonymous pages? If it was not intended, it would scream for a cleanup. > > - Xinhai > -- Thanks, David / dhildenb
