• V
    memcg: do not abuse memcg_kmem_skip_account · 95fc3c50
    Vladimir Davydov 提交于
    task_struct->memcg_kmem_skip_account was initially introduced to avoid
    recursion during kmem cache creation: memcg_kmem_get_cache, which is
    called by kmem_cache_alloc to determine the per-memcg cache to account
    allocation to, may issue lazy cache creation if the needed cache doesn't
    exist, which means issuing yet another kmem_cache_alloc.  We can't just
    pass a flag to the nested kmem_cache_alloc disabling kmem accounting,
    because there are hidden allocations, e.g.  in INIT_WORK.  So we
    introduced a flag on the task_struct, memcg_kmem_skip_account, making
    memcg_kmem_get_cache return immediately.
    
    By its nature, the flag may also be used to disable accounting for
    allocations shared among different cgroups, and currently it is used this
    way in memcg_activate_kmem.  Using it like this looks like abusing it to
    me.  If we want to disable accounting for some allocations (which we will
    definitely want one day), we should either add GFP_NO_MEMCG or GFP_MEMCG
    flag in order to blacklist/whitelist some allocations.
    
    For now, let's simply remove memcg_stop/resume_kmem_account from
    memcg_activate_kmem.
    Signed-off-by: NVladimir Davydov <vdavydov@parallels.com>
    Cc: Johannes Weiner <hannes@cmpxchg.org>
    Cc: Michal Hocko <mhocko@suse.cz>
    Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
    95fc3c50
memcontrol.c 151.6 KB