lkml.org 
[lkml]   [2009]   [Jan]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    Subject[RFC][PATCH 3/4] memcg: fix OOM KILL under hierarchy

    From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

    Current memcg's oom-killer has 2 problems when hierarchy is used.

    Assume following tree,
    Group_A/ use_hierarchy = 1, limit=1G
    01/ nolimit
    02/ nolimit
    03/ nolimit
    In this case, sum of memory usage from 01,02,03 is limited to 1G (of Group_A).

    Assume a task in Group_A/01 causes OOM by limit of Group_A, in this case,
    bad_process() will select a process in Group_A, not in 01,02,03.

    This patch fixes the behavior and all processes under Group_A's hierarchy
    01,02,03 will be OOM kill candidates.

    And now, to avoid calling oom_kill twice, mem_cgroup_oom_called() hook is
    used in pagefault_out_of_memory(). This check the timestamp of the most
    recent OOM in memcg. This timestamp should be updated per hierarchy.

    Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>


    ---
    Documentation/controllers/memcg_test.txt | 15 ++++++++
    include/linux/memcontrol.h | 4 +-
    mm/memcontrol.c | 55 +++++++++++++++++++++++++++++--
    mm/oom_kill.c | 4 +-
    4 files changed, 72 insertions(+), 6 deletions(-)

    Index: mmotm-2.6.28-Jan7/mm/memcontrol.c
    ===================================================================
    --- mmotm-2.6.28-Jan7.orig/mm/memcontrol.c
    +++ mmotm-2.6.28-Jan7/mm/memcontrol.c
    @@ -431,12 +431,31 @@ void mem_cgroup_move_lists(struct page *
    mem_cgroup_add_lru_list(page, to);
    }

    -int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem)
    +static int
    +mm_match_cgroup_hierarchy(struct mm_struct *mm, struct mem_cgroup *mem)
    +{
    + struct mem_cgroup *curr;
    + int ret;
    +
    + if (!mm)
    + return 0;
    + rcu_read_lock();
    + curr = mem_cgroup_from_task(mm->owner);
    + if (mem->use_hierarchy)
    + ret = css_is_ancestor(&curr->css, &mem->css);
    + else
    + ret = (curr == mem);
    + rcu_read_unlock();
    + return ret;
    +}
    +
    +int task_in_mem_cgroup_hierarchy(struct task_struct *task,
    + struct mem_cgroup *mem)
    {
    int ret;

    task_lock(task);
    - ret = task->mm && mm_match_cgroup(task->mm, mem);
    + ret = mm_match_cgroup_hierarchy(task->mm, mem);
    task_unlock(task);
    return ret;
    }
    @@ -723,6 +742,36 @@ static int mem_cgroup_hierarchical_recla
    return total;
    }

    +/*
    + * Update last_oom_jiffies of hierarchy.
    + */
    +void mem_cgroup_update_oom_jiffies(struct mem_cgroup *mem)
    +{
    + struct mem_cgroup *cur;
    + struct cgroup_subsys_state *css;
    + int id, found;
    +
    + if (!mem->use_hierarchy) {
    + mem->last_oom_jiffies = jiffies;
    + return;
    + }
    +
    + id = 0;
    + rcu_read_lock();
    + while (1) {
    + css = css_get_next(&mem_cgroup_subsys, id, &mem->css, &found);
    + if (!css)
    + break;
    + if (css_tryget(css)) {
    + cur = container_of(css, struct mem_cgroup, css);
    + cur->last_oom_jiffies = jiffies;
    + css_put(css);
    + }
    + id = found + 1;
    + }
    + rcu_read_unlock();
    + return;
    +}
    bool mem_cgroup_oom_called(struct task_struct *task)
    {
    bool ret = false;
    @@ -819,7 +868,7 @@ static int __mem_cgroup_try_charge(struc
    mutex_lock(&memcg_tasklist);
    mem_cgroup_out_of_memory(mem_over_limit, gfp_mask);
    mutex_unlock(&memcg_tasklist);
    - mem_over_limit->last_oom_jiffies = jiffies;
    + mem_cgroup_update_oom_jiffies(mem_over_limit);
    }
    goto nomem;
    }
    Index: mmotm-2.6.28-Jan7/include/linux/memcontrol.h
    ===================================================================
    --- mmotm-2.6.28-Jan7.orig/include/linux/memcontrol.h
    +++ mmotm-2.6.28-Jan7/include/linux/memcontrol.h
    @@ -66,7 +66,9 @@ extern unsigned long mem_cgroup_isolate_
    struct mem_cgroup *mem_cont,
    int active, int file);
    extern void mem_cgroup_out_of_memory(struct mem_cgroup *mem, gfp_t gfp_mask);
    -int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem);
    +
    +int task_in_mem_cgroup_hierarchy(struct task_struct *task,
    + struct mem_cgroup *mem);

    extern struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p);

    Index: mmotm-2.6.28-Jan7/mm/oom_kill.c
    ===================================================================
    --- mmotm-2.6.28-Jan7.orig/mm/oom_kill.c
    +++ mmotm-2.6.28-Jan7/mm/oom_kill.c
    @@ -220,7 +220,7 @@ static struct task_struct *select_bad_pr
    /* skip the init task */
    if (is_global_init(p))
    continue;
    - if (mem && !task_in_mem_cgroup(p, mem))
    + if (mem && !task_in_mem_cgroup_hierarchy(p, mem))
    continue;

    /*
    @@ -292,7 +292,7 @@ static void dump_tasks(const struct mem_
    */
    if (!p->mm)
    continue;
    - if (mem && !task_in_mem_cgroup(p, mem))
    + if (mem && !task_in_mem_cgroup_hierarchy(p, mem))
    continue;
    if (!thread_group_leader(p))
    continue;
    Index: mmotm-2.6.28-Jan7/Documentation/controllers/memcg_test.txt
    ===================================================================
    --- mmotm-2.6.28-Jan7.orig/Documentation/controllers/memcg_test.txt
    +++ mmotm-2.6.28-Jan7/Documentation/controllers/memcg_test.txt
    @@ -340,3 +340,18 @@ Under below explanation, we assume CONFI
    # mount -t cgroup none /cgroup -t cpuset,memory,cpu,devices

    and do task move, mkdir, rmdir etc...under this.
    +
    + 9.7 OOM-KILL
    + If memcg finds out-of-memory, OOM Kill should kill a task in memcg.
    + The select_bad_process() should take hierarchy into account and
    + OOM-KILL itself shoudn't call panic_on_oom or some hooks for generic
    + OOM.
    +
    + It's not difficult to cause OOM under memcg by setting memsw.limit
    + as following.
    + # echo 50M > memory.limit_in_bytes
    + # echo 50M > memory.memsw.limit_in_bytes
    + and run malloc(51M) program.
    + (Alternative is do swapoff/mlock and malloc())
    +
    +


    \
     
     \ /
      Last update: 2009-01-08 10:35    [W:0.028 / U:137.268 seconds]
    ©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site