Commit 58cf188e authored by Sha Zhengju's avatar Sha Zhengju Committed by Linus Torvalds
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memcg, oom: provide more precise dump info while memcg oom happening



Currently when a memcg oom is happening the oom dump messages is still
global state and provides few useful info for users.  This patch prints
more pointed memcg page statistics for memcg-oom and take hierarchy into
consideration:

Based on Michal's advice, we take hierarchy into consideration: supppose
we trigger an OOM on A's limit

        root_memcg
            |
            A (use_hierachy=1)
           / \
          B   C
          |
          D
then the printed info will be:

  Memory cgroup stats for /A:...
  Memory cgroup stats for /A/B:...
  Memory cgroup stats for /A/C:...
  Memory cgroup stats for /A/B/D:...

Following are samples of oom output:

(1) Before change:

    mal-80 invoked oom-killer:gfp_mask=0xd0, order=0, oom_score_adj=0
    mal-80 cpuset=/ mems_allowed=0
    Pid: 2976, comm: mal-80 Not tainted 3.7.0+ #10
    Call Trace:
     [<ffffffff8167fbfb>] dump_header+0x83/0x1ca
     ..... (call trace)
     [<ffffffff8168a818>] page_fault+0x28/0x30
                             <<<<<<<<<<<<<<<<<<<<< memcg specific information
    Task in /A/B/D killed as a result of limit of /A
    memory: usage 101376kB, limit 101376kB, failcnt 57
    memory+swap: usage 101376kB, limit 101376kB, failcnt 0
    kmem: usage 0kB, limit 9007199254740991kB, failcnt 0
                             <<<<<<<<<<<<<<<<<<<<< print per cpu pageset stat
    Mem-Info:
    Node 0 DMA per-cpu:
    CPU    0: hi:    0, btch:   1 usd:   0
    ......
    CPU    3: hi:    0, btch:   1 usd:   0
    Node 0 DMA32 per-cpu:
    CPU    0: hi:  186, btch:  31 usd: 173
    ......
    CPU    3: hi:  186, btch:  31 usd: 130
                             <<<<<<<<<<<<<<<<<<<<< print global page state
    active_anon:92963 inactive_anon:40777 isolated_anon:0
     active_file:33027 inactive_file:51718 isolated_file:0
     unevictable:0 dirty:3 writeback:0 unstable:0
     free:729995 slab_reclaimable:6897 slab_unreclaimable:6263
     mapped:20278 shmem:35971 pagetables:5885 bounce:0
     free_cma:0
                             <<<<<<<<<<<<<<<<<<<<< print per zone page state
    Node 0 DMA free:15836kB ... all_unreclaimable? no
    lowmem_reserve[]: 0 3175 3899 3899
    Node 0 DMA32 free:2888564kB ... all_unrelaimable? no
    lowmem_reserve[]: 0 0 724 724
    lowmem_reserve[]: 0 0 0 0
    Node 0 DMA: 1*4kB (U) ... 3*4096kB (M) = 15836kB
    Node 0 DMA32: 41*4kB (UM) ... 702*4096kB (MR) = 2888316kB
    120710 total pagecache pages
    0 pages in swap cache
                             <<<<<<<<<<<<<<<<<<<<< print global swap cache stat
    Swap cache stats: add 0, delete 0, find 0/0
    Free swap  = 499708kB
    Total swap = 499708kB
    1040368 pages RAM
    58678 pages reserved
    169065 pages shared
    173632 pages non-shared
    [ pid ]   uid  tgid total_vm      rss nr_ptes swapents oom_score_adj name
    [ 2693]     0  2693     6005     1324      17        0             0 god
    [ 2754]     0  2754     6003     1320      16        0             0 god
    [ 2811]     0  2811     5992     1304      18        0             0 god
    [ 2874]     0  2874     6005     1323      18        0             0 god
    [ 2935]     0  2935     8720     7742      21        0             0 mal-30
    [ 2976]     0  2976    21520    17577      42        0             0 mal-80
    Memory cgroup out of memory: Kill process 2976 (mal-80) score 665 or sacrifice child
    Killed process 2976 (mal-80) total-vm:86080kB, anon-rss:69964kB, file-rss:344kB

We can see that messages dumped by show_free_areas() are longsome and can
provide so limited info for memcg that just happen oom.

(2) After change
    mal-80 invoked oom-killer: gfp_mask=0xd0, order=0, oom_score_adj=0
    mal-80 cpuset=/ mems_allowed=0
    Pid: 2704, comm: mal-80 Not tainted 3.7.0+ #10
    Call Trace:
     [<ffffffff8167fd0b>] dump_header+0x83/0x1d1
     .......(call trace)
     [<ffffffff8168a918>] page_fault+0x28/0x30
    Task in /A/B/D killed as a result of limit of /A
                             <<<<<<<<<<<<<<<<<<<<< memcg specific information
    memory: usage 102400kB, limit 102400kB, failcnt 140
    memory+swap: usage 102400kB, limit 102400kB, failcnt 0
    kmem: usage 0kB, limit 9007199254740991kB, failcnt 0
    Memory cgroup stats for /A: cache:32KB rss:30984KB mapped_file:0KB swap:0KB inactive_anon:6912KB active_anon:24072KB inactive_file:32KB active_file:0KB unevictable:0KB
    Memory cgroup stats for /A/B: cache:0KB rss:0KB mapped_file:0KB swap:0KB inactive_anon:0KB active_anon:0KB inactive_file:0KB active_file:0KB unevictable:0KB
    Memory cgroup stats for /A/C: cache:0KB rss:0KB mapped_file:0KB swap:0KB inactive_anon:0KB active_anon:0KB inactive_file:0KB active_file:0KB unevictable:0KB
    Memory cgroup stats for /A/B/D: cache:32KB rss:71352KB mapped_file:0KB swap:0KB inactive_anon:6656KB active_anon:64696KB inactive_file:16KB active_file:16KB unevictable:0KB
    [ pid ]   uid  tgid total_vm      rss nr_ptes swapents oom_score_adj name
    [ 2260]     0  2260     6006     1325      18        0             0 god
    [ 2383]     0  2383     6003     1319      17        0             0 god
    [ 2503]     0  2503     6004     1321      18        0             0 god
    [ 2622]     0  2622     6004     1321      16        0             0 god
    [ 2695]     0  2695     8720     7741      22        0             0 mal-30
    [ 2704]     0  2704    21520    17839      43        0             0 mal-80
    Memory cgroup out of memory: Kill process 2704 (mal-80) score 669 or sacrifice child
    Killed process 2704 (mal-80) total-vm:86080kB, anon-rss:71016kB, file-rss:340kB

This version provides more pointed info for memcg in "Memory cgroup stats
for XXX" section.
Signed-off-by: default avatarSha Zhengju <handai.szj@taobao.com>
Acked-by: default avatarMichal Hocko <mhocko@suse.cz>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: default avatarDavid Rientjes <rientjes@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent df855798
......@@ -120,6 +120,14 @@ static const char * const mem_cgroup_events_names[] = {
"pgmajfault",
};
static const char * const mem_cgroup_lru_names[] = {
"inactive_anon",
"active_anon",
"inactive_file",
"active_file",
"unevictable",
};
/*
* Per memcg event counter is incremented at every pagein/pageout. With THP,
* it will be incremated by the number of pages. This counter is used for
......@@ -1524,8 +1532,9 @@ static void move_unlock_mem_cgroup(struct mem_cgroup *memcg,
spin_unlock_irqrestore(&memcg->move_lock, *flags);
}
#define K(x) ((x) << (PAGE_SHIFT-10))
/**
* mem_cgroup_print_oom_info: Called from OOM with tasklist_lock held in read mode.
* mem_cgroup_print_oom_info: Print OOM information relevant to memory controller.
* @memcg: The memory cgroup that went over limit
* @p: Task that is going to be killed
*
......@@ -1543,8 +1552,10 @@ void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
*/
static char memcg_name[PATH_MAX];
int ret;
struct mem_cgroup *iter;
unsigned int i;
if (!memcg || !p)
if (!p)
return;
rcu_read_lock();
......@@ -1592,6 +1603,30 @@ done:
res_counter_read_u64(&memcg->kmem, RES_USAGE) >> 10,
res_counter_read_u64(&memcg->kmem, RES_LIMIT) >> 10,
res_counter_read_u64(&memcg->kmem, RES_FAILCNT));
for_each_mem_cgroup_tree(iter, memcg) {
pr_info("Memory cgroup stats");
rcu_read_lock();
ret = cgroup_path(iter->css.cgroup, memcg_name, PATH_MAX);
if (!ret)
pr_cont(" for %s", memcg_name);
rcu_read_unlock();
pr_cont(":");
for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account)
continue;
pr_cont(" %s:%ldKB", mem_cgroup_stat_names[i],
K(mem_cgroup_read_stat(iter, i)));
}
for (i = 0; i < NR_LRU_LISTS; i++)
pr_cont(" %s:%luKB", mem_cgroup_lru_names[i],
K(mem_cgroup_nr_lru_pages(iter, BIT(i))));
pr_cont("\n");
}
}
/*
......@@ -5214,14 +5249,6 @@ static int memcg_numa_stat_show(struct cgroup *cont, struct cftype *cft,
}
#endif /* CONFIG_NUMA */
static const char * const mem_cgroup_lru_names[] = {
"inactive_anon",
"active_anon",
"inactive_file",
"active_file",
"unevictable",
};
static inline void mem_cgroup_lru_names_not_uptodate(void)
{
BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_lru_names) != NR_LRU_LISTS);
......
......@@ -386,8 +386,10 @@ static void dump_header(struct task_struct *p, gfp_t gfp_mask, int order,
cpuset_print_task_mems_allowed(current);
task_unlock(current);
dump_stack();
mem_cgroup_print_oom_info(memcg, p);
show_mem(SHOW_MEM_FILTER_NODES);
if (memcg)
mem_cgroup_print_oom_info(memcg, p);
else
show_mem(SHOW_MEM_FILTER_NODES);
if (sysctl_oom_dump_tasks)
dump_tasks(memcg, nodemask);
}
......
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