The patch doesn't apply cleanly on top of the current mm tree. The
resolving is trivial but please make sure you work on top of the latest
mmotm tree (or -mm git tree since-3.7 branch at the moment).
This also touches mm/oom_kill.c so please add David into the CC list.
More comments below.
On Mon 17-12-12 19:03:07, Sha Zhengju wrote:
> From: Sha Zhengju <handai.szj@xxxxxxxxxx>
>
> Current 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:
> [ 204.308085] mal-80 invoked oom-killer: gfp_mask=0xd0, order=0, oom_score_adj=0
> [ 204.308088] mal-80 cpuset=/ mems_allowed=0
> [ 204.308090] Pid: 2376, comm: mal-80 Not tainted 3.7.0+ #4
> [ 204.308091] Call Trace:
> [ 204.308100] [<ffffffff81692515>] dump_header+0x83/0x1ca
> [ 204.308107] [<ffffffff8112effe>] oom_kill_process+0x1be/0x320
> ..... (call trace)
> [ 204.308146] [<ffffffff8169c418>] page_fault+0x28/0x30
> [ 204.308148] Task in /1/2 killed as a result of limit of /1
> [ 204.308150] memory: usage 102400kB, limit 102400kB, failcnt 181
> [ 204.308151] memory+swap: usage 102400kB, limit 102400kB, failcnt 0
> [ 204.308151] Mem-Info:
> [ 204.308152] Node 0 DMA per-cpu: <<<<<<<<<<<<<<<<<<<<< print per cpu pageset stat
> [ 204.308154] CPU 0: hi: 0, btch: 1 usd: 0
> ......
> [ 204.308157] CPU 3: hi: 0, btch: 1 usd: 0
> [ 204.308158] Node 0 DMA32 per-cpu:
> [ 204.308159] CPU 0: hi: 186, btch: 31 usd: 134
> ......
> [ 204.308162] CPU 3: hi: 186, btch: 31 usd: 141
> <<<<<<<<<<<<<<<<<<<<< print global page state
> [ 204.308169] active_anon:94139 inactive_anon:41771 isolated_anon:0
> [ 204.308169] active_file:24655 inactive_file:60269 isolated_file:0
> [ 204.308169] unevictable:0 dirty:11 writeback:0 unstable:0
> [ 204.308169] free:729657 slab_reclaimable:6861 slab_unreclaimable:6199
> [ 204.308169] mapped:28794 shmem:35794 pagetables:5774 bounce:0
> [ 204.308169] free_cma:0
> <<<<<<<<<<<<<<<<<<<<< print per zone page state
> [ 204.308171] Node 0 DMA free:15836kB min:260kB low:324kB high:388kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:15596kB managed:15852kB mlocked:0kB dirty:0kB writeback:0kB mapped:0kB shmem:0kB slab_reclaimable:0kB slab_unreclaimable:16kB kernel_stack:0kB pagetables:0kB unstable:0kB bounce:0kB free_cma:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no
> [ 204.308174] lowmem_reserve[]: 0 3175 3899 3899
> [ 204.308176] Node 0 DMA32 free:2887244kB ...
> [ 204.308174] lowmem_reserve[]: 0 3175 3899 3899
> [ 204.308176] Node 0 DMA32 free:2887244kB ...
> [ 204.308185] lowmem_reserve[]: 0 0 0 0
> [ 204.308187] Node 0 DMA: 1*4kB (U) 1*8kB (U) ...
> [ 204.308196] Node 0 DMA32: 21*4kB (UEM) 58*8kB (UE) ...
> [ 204.308213] 120727 total pagecache pages
> [ 204.308214] 0 pages in swap cache
> <<<<<<<<<<<<<<<<<<<<< print global swap cache stat
> [ 204.308215] Swap cache stats: add 0, delete 0, find 0/0
> [ 204.308215] Free swap = 499708kB
> [ 204.308216] Total swap = 499708kB
> [ 204.316300] 1040368 pages RAM
> [ 204.316304] 58707 pages reserved
> [ 204.316308] 175021 pages shared
> [ 204.316312] 174709 pages non-shared
Could you add:
<<<<<<<<<<<<<<<<<<<<< Finally memcg specific information
> [ 204.316315] [ pid ] uid tgid total_vm rss nr_ptes swapents oom_score_adj name
> [ 204.316348] [ 1996] 1000 1996 6007 1324 17 0 0 bash
> [ 204.316354] [ 2283] 1000 2283 6008 1324 18 0 0 bash
> [ 204.316356] [ 2367] 1000 2367 8721 7742 22 0 0 mal-30
> [ 204.316358] [ 2376] 1000 2376 21521 17841 43 0 0 mal-80
> [ 204.316359] Memory cgroup out of memory: Kill process 2376 (mal-80) score 698 or sacrifice child
> [ 204.316361] Killed process 2376 (mal-80) total-vm:86084kB, anon-rss:71020kB, 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.
No need to use long line here.
> (2) After change
> [ 328.035727] mal-80 invoked oom-killer: gfp_mask=0xd0, order=0, oom_score_adj=0
> [ 328.035730] mal-80 cpuset=/ mems_allowed=0
> [ 328.035732] Pid: 2439, comm: mal-80 Not tainted 3.7.0+ #5
> [ 328.035733] Call Trace:
> [ 328.035743] [<ffffffff81692625>] dump_header+0x83/0x1d1
> .......(call trace)
> [ 328.035793] Task in /1/2 killed as a result of limit of /1
Would be nice if the naming was consistent with your hierarchy scheme above ;)
> [ 328.035795] memory: usage 101376kB, limit 101376kB, failcnt 815
> [ 328.035796] memory+swap: usage 101376kB, limit 101376kB, failcnt 0
> [ 328.035797] Memory cgroup stats for /1:cache:0KB rss:31052KB mapped_file:0KB swap:0KB inactive_anon:15620KB active_anon:15432KB inactive_file:0KB active_file:0KB unevictable:0KB
> [ 328.035804] Memory cgroup stats for /1/2:cache:44KB rss:70280KB mapped_file:0KB swap:0KB inactive_anon:16640KB active_anon:53608KB inactive_file:44KB active_file:0KB unevictable:0KB
Same above
> [ 328.035809] [ pid ] uid tgid total_vm rss nr_ptes swapents oom_score_adj name
> [ 328.035841] [ 2239] 0 2239 6005 1322 17 0 0 god
> [ 328.035843] [ 2361] 0 2361 6004 1321 17 0 0 god
> [ 328.035845] [ 2437] 0 2437 8721 7741 22 0 0 mal-30
> [ 328.035846] [ 2439] 0 2439 21521 17575 42 0 0 mal-80
> [ 328.035847] Memory cgroup out of memory: Kill process 2439 (mal-80) score 665 or sacrifice child
> [ 328.035849] Killed process 2439 (mal-80) total-vm:86084kB, anon-rss:69960kB, file-rss:340kB
Yes the output is nice and useful. I like it!
> This version provides more pointed info for memcg in "Memory cgroup stats" section.
long line again
>
> Change log:
> v4 <--- v3
> 1. print more info in hierarchy
> v3 <--- v2
> 1. fix towards hierarchy
> 2. undo rework dump_tasks
> v2 <--- v1
> 1. some modification towards hierarchy
> 2. rework dump_tasks
> 3. rebased on Michal's mm tree since-3.6
>
> Signed-off-by: Sha Zhengju <handai.szj@xxxxxxxxxx>
The changelog could have been cleaner but the point is clear.
Appart from that just a nit bellow but feel free to add my
Acked-by: Michal Hocko <mhocko@xxxxxxx>
Thanks!
> ---
> mm/memcontrol.c | 47 +++++++++++++++++++++++++++++++++++++----------
> mm/oom_kill.c | 6 ++++--
> 2 files changed, 41 insertions(+), 12 deletions(-)
>
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index bbfac50..e2d17c8 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
[...]
> @@ -1453,6 +1464,30 @@ done:
> res_counter_read_u64(&memcg->memsw, RES_USAGE) >> 10,
> res_counter_read_u64(&memcg->memsw, RES_LIMIT) >> 10,
> res_counter_read_u64(&memcg->memsw, 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)));
one space before %s wihtout trailing space would be nicer.
> + }
> +
> + 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))));
same here
> +
> + pr_cont("\n");
> + }
> }
>
> /*
[...]
--
Michal Hocko
SUSE Labs
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