From: Muchun Song songmuchun@bytedance.com
page_memcg() is not suitable for use by page_expected_state() and page_bad_reason(). Because it can BUG_ON() for the slab pages when CONFIG_DEBUG_VM is enabled. As neither lru, nor kmem, nor slab page should have anything left in there by the time the page is freed, what we care about is whether the value of page->memcg_data is 0. So just directly access page->memcg_data here.
Link: https://lkml.kernel.org/r/20210319163821.20704-4-songmuchun@bytedance.com Signed-off-by: Muchun Song songmuchun@bytedance.com Acked-by: Johannes Weiner hannes@cmpxchg.org Reviewed-by: Shakeel Butt shakeelb@google.com Cc: Michal Hocko mhocko@kernel.org Cc: Roman Gushchin guro@fb.com Cc: Vladimir Davydov vdavydov.dev@gmail.com Cc: Xiongchun Duan duanxiongchun@bytedance.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Chen Huang chenhuang5@huawei.com --- mm/page_alloc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 8ec194271b91..12deac86a7ac 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1094,7 +1094,7 @@ static inline bool page_expected_state(struct page *page, if (unlikely((unsigned long)page->mapping | page_ref_count(page) | #ifdef CONFIG_MEMCG - (unsigned long)page_memcg(page) | + page->memcg_data | #endif (page->flags & check_flags))) return false; @@ -1119,7 +1119,7 @@ static const char *page_bad_reason(struct page *page, unsigned long flags) bad_reason = "PAGE_FLAGS_CHECK_AT_FREE flag(s) set"; } #ifdef CONFIG_MEMCG - if (unlikely(page_memcg(page))) + if (unlikely(page->memcg_data)) bad_reason = "page still charged to cgroup"; #endif return bad_reason;