Commit 48060834 authored by Muchun Song's avatar Muchun Song Committed by Linus Torvalds
Browse files

mm: memcontrol: directly access page->memcg_data in mm/page_alloc.c 

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: default avatarMuchun Song <songmuchun@bytedance.com>
Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Reviewed-by: default avatarShakeel 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e74d2259

mm/page_alloc.c

+2 −2
Original line number Diff line number Diff line
@@ -1103,7 +1103,7 @@ 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;
@@ -1128,7 +1128,7 @@ 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;