• Vladimir Davydov's avatar
    memcg: fix kmem_account_flags check in memcg_can_account_kmem() · 1c98dd90
    Vladimir Davydov authored
    We should start kmem accounting for a memory cgroup only after both its
    kmem limit is set (KMEM_ACCOUNTED_ACTIVE) and related call sites are
    patched (KMEM_ACCOUNTED_ACTIVATED).  Currently memcg_can_account_kmem()
    allows kmem accounting even if only one of the conditions is true.  Fix
    it.
    
    This means that a page might get charged by memcg_kmem_newpage_charge
    which would see its static key patched already but
    memcg_kmem_commit_charge would still see it unpatched and so the charge
    won't be committed.  The result would be charge inconsistency
    (page_cgroup not marked as PageCgroupUsed) and the charge would leak
    because __memcg_kmem_uncharge_pages would ignore it.
    
    [mhocko@suse.cz: augment changelog]
    Signed-off-by: default avatarVladimir Davydov <vdavydov@parallels.com>
    Cc: Johannes Weiner <hannes@cmpxchg.org>
    Acked-by: default avatarMichal Hocko <mhocko@suse.cz>
    Cc: Balbir Singh <bsingharora@gmail.com>
    Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
    Cc: Glauber Costa <glommer@parallels.com>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    1c98dd90
memcontrol.c 188 KB