lkml.org 
[lkml]   [2012]   [Feb]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH next] memcg: remove PCG_CACHE page_cgroup flag fix
    On Tue, Feb 28, 2012 at 09:30:17PM -0800, Hugh Dickins wrote:
    > Swapping tmpfs loads show absurd wrapped rss and wrong cache in memcg's
    > memory.stat statistics: __mem_cgroup_uncharge_common() is failing to
    > distinguish the anon and tmpfs cases.
    >
    > Mostly we can decide between them by PageAnon, which is reliable once
    > it has been set; but there are several callers who need to uncharge a
    > MEM_CGROUP_CHARGE_TYPE_MAPPED page before it was fully initialized,
    > so allow that case to override the PageAnon decision.
    >
    > Signed-off-by: Hugh Dickins <hughd@google.com>
    > ---
    >
    > mm/memcontrol.c | 7 ++++---
    > 1 file changed, 4 insertions(+), 3 deletions(-)
    >
    > --- 3.3-rc5-next/mm/memcontrol.c 2012-02-25 10:06:52.496035568 -0800
    > +++ linux/mm/memcontrol.c 2012-02-26 10:44:32.146365398 -0800
    > @@ -2944,13 +2944,16 @@ __mem_cgroup_uncharge_common(struct page
    > if (!PageCgroupUsed(pc))
    > goto unlock_out;
    >
    > + anon = PageAnon(page);
    > +
    > switch (ctype) {
    > case MEM_CGROUP_CHARGE_TYPE_MAPPED:
    > + anon = true;
    > + /* fallthrough */

    If you don't mind, could you add a small comment on why this is the
    exception where we don't trust page->mapping?

    Other than that,
    Acked-by: Johannes Weiner <hannes@cmpxchg.org>

    > case MEM_CGROUP_CHARGE_TYPE_DROP:
    > /* See mem_cgroup_prepare_migration() */
    > if (page_mapped(page) || PageCgroupMigration(pc))
    > goto unlock_out;
    > - anon = true;
    > break;
    > case MEM_CGROUP_CHARGE_TYPE_SWAPOUT:
    > if (!PageAnon(page)) { /* Shared memory */
    > @@ -2958,10 +2961,8 @@ __mem_cgroup_uncharge_common(struct page
    > goto unlock_out;
    > } else if (page_mapped(page)) /* Anon */
    > goto unlock_out;
    > - anon = true;
    > break;
    > default:
    > - anon = false;
    > break;
    > }


    \
     
     \ /
      Last update: 2012-02-29 20:45    [W:0.023 / U:0.260 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site