Reading /proc/kpageflags for any anonymous page returns KPF_KSM set, even when KSM is not in use. As a result, tools misclassify all anonymous pages as KSM merged. In stable_page_flags(), if the page is anonymous, then use (mapping & FOLIO_MAPPING_KSM) check to identify if the anonymous page is KSM page. However, FOLIO_MAPPING_KSM is FOLIO_MAPPING_ANON | FOLIO_MAPPING_ANON_KSM, (mapping & FOLIO_MAPPING_KSM) check returns true for all nonymous pages. To fix it, use FOLIO_MAPPING_ANON_KSM instead. Fixes: dee3d0bef2b0 ("proc: rewrite stable_page_flags()") Signed-off-by: Jinjiang Tu --- fs/proc/page.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/proc/page.c b/fs/proc/page.c index f9b2c2c906cd..cef8ded97610 100644 --- a/fs/proc/page.c +++ b/fs/proc/page.c @@ -173,7 +173,7 @@ u64 stable_page_flags(const struct page *page) u |= 1 << KPF_MMAP; if (is_anon) { u |= 1 << KPF_ANON; - if (mapping & FOLIO_MAPPING_KSM) + if (mapping & FOLIO_MAPPING_ANON_KSM) u |= 1 << KPF_KSM; } -- 2.43.0