[PATCH V3] memcg, oom: provide more precise dump info while memcg oom happening

From: Sha Zhengju
Date: Thu Nov 08 2012 - 10:52:52 EST


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.


We set up a simple cgroup hierarchy for test:
root_memcg
|
1 (use_hierachy=1, with a process)
|
2 (its process will be killed by memcg oom)

Following are samples of oom output:

(1)Before change:

[ 295.754215] mal invoked oom-killer: gfp_mask=0xd0, order=0, oom_score_adj=0
[ 295.754219] mal cpuset=/ mems_allowed=0-1
[ 295.754221] Pid: 4623, comm: mal Not tainted 3.6.0+ #26
[ 295.754223] Call Trace:
[ 295.754230] [<ffffffff8111b9c4>] dump_header+0x84/0xd0
[ 295.754233] [<ffffffff8111c691>] oom_kill_process+0x331/0x350
..... (call trace)
[ 295.754288] [<ffffffff815171e5>] page_fault+0x25/0x30
[ 295.754291] Task in /1/2 killed as a result of limit of /1
[ 295.754293] memory: usage 511640kB, limit 512000kB, failcnt 4471
[ 295.754294] memory+swap: usage 563200kB, limit 563200kB, failcnt 22
[ 295.754296] kmem: usage 0kB, limit 9007199254740991kB, failcnt 0
[ 295.754297] Mem-Info:
[ 295.754298] Node 0 DMA per-cpu: <<<<<<<<<<<<<<<<<<<<< print per cpu pageset stat
[ 295.754300] CPU 0: hi: 0, btch: 1 usd: 0
......
[ 295.754302] CPU 15: hi: 0, btch: 1 usd: 0

[ 295.754448] Node 0 DMA32 per-cpu:
[ 295.754450] CPU 0: hi: 186, btch: 31 usd: 181
......
[ 295.754451] CPU 15: hi: 186, btch: 31 usd: 25

[ 295.754470] Node 0 Normal per-cpu:
[ 295.754472] CPU 0: hi: 186, btch: 31 usd: 56
......
[ 295.754473] CPU 15: hi: 186, btch: 31 usd: 150

[ 295.754493] Node 1 Normal per-cpu:
[ 295.754495] CPU 0: hi: 186, btch: 31 usd: 0
......
[ 295.754496] CPU 15: hi: 186, btch: 31 usd: 0
<<<<<<<<<<<<<<<<<<<<< print global page state
[ 295.754519] active_anon:57756 inactive_anon:73437 isolated_anon:0
[ 295.754519] active_file:2659 inactive_file:14291 isolated_file:0
[ 295.754519] unevictable:1268 dirty:0 writeback:4961 unstable:0
[ 295.754519] free:5979740 slab_reclaimable:2955 slab_unreclaimable:5460
[ 295.754519] mapped:2478 shmem:62 pagetables:994 bounce:0
[ 295.754519] free_cma:0
<<<<<<<<<<<<<<<<<<<<< print per zone page state
[ 295.754522] Node 0 DMA free:15884kB min:56kB low:68kB high:84kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:15884kB mlocked:0kB dirty:0kB writeback:0kB mapped:0kB shmem:0kB slab_reclaimable:0kB slab_unreclaimable:0kB kernel_stack:0kB pagetables:0kB unstable:0kB bounce:0kB free_cma:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no
[ 295.754527] lowmem_reserve[]: 0 2966 12013 12013
[ 295.754530] Node 0 DMA32 free:3041228kB min:11072kB .....
[ 295.754535] lowmem_reserve[]: 0 0 9046 9046
[ 295.754537] Node 0 Normal free:8616716kB min:33756kB .....
[ 295.754542] lowmem_reserve[]: 0 0 0 0
[ 295.754545] Node 1 Normal free:12245132kB min:45220kB ....
[ 295.754550] lowmem_reserve[]: 0 0 0 0
[ 295.754552] Node 0 DMA: 1*4kB (U) 1*8kB (U) 0*16kB 0*32kB 2*64kB (U) 1*128kB (U) 1*256kB (U) 0*512kB 1*1024kB (U) 1*2048kB (R) 3*4096kB (M) = 15884kB
[ 295.754563] Node 0 DMA32: 5*4kB (M) 3*8kB (M) 6*16kB (UM) ... 738*4096kB (MR) = 3041228kB
[ 295.754574] Node 0 Normal: 16*4kB (EM) 165*8kB (UEM) ... 2101*4096kB (MR) = 8616840kB
[ 295.754586] Node 1 Normal: 768*4kB (UEM) 924*8kB (UEM) ... 048kB (EM) 2976*4096kB (MR) = 12245264kB
[ 295.754598] 25266 total pagecache pages
[ 295.754599] 7227 pages in swap cache
<<<<<<<<<<<<<<<<<<<<< print global swap cache stat
[ 295.754600] Swap cache stats: add 21474, delete 14247, find 533/576
[ 295.754601] Free swap = 2016000kB
[ 295.754602] Total swap = 2096444kB
[ 295.816119] 6291440 pages RAM
[ 295.816121] 108291 pages reserved
[ 295.816122] 9427 pages shared
[ 295.816123] 195843 pages non-shared
[ 295.816124] [ pid ] uid tgid total_vm rss nr_ptes swapents oom_score_adj name
[ 295.816161] [ 4569] 0 4569 16626 475 18 30 0 bash
[ 295.816164] [ 4622] 0 4622 103328 87541 208 14950 0 mal
[ 295.816167] [ 4623] 0 4623 103328 33468 85 5162 0 mal
[ 295.816171] Memory cgroup out of memory: Kill process 4622 (mal) score 699 or sacrifice child
[ 295.816173] Killed process 4622 (mal) total-vm:413312kB, anon-rss:349872kB, file-rss:292kB

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
[ 269.225628] mal invoked oom-killer: gfp_mask=0xd0, order=0, oom_score_adj=0
[ 269.225633] mal cpuset=/ mems_allowed=0-1
[ 269.225636] Pid: 4616, comm: mal Not tainted 3.6.0+ #25
[ 269.225637] Call Trace:
[ 269.225647] [<ffffffff8111b9c4>] dump_header+0x84/0xd0
[ 269.225650] [<ffffffff8111c691>] oom_kill_process+0x331/0x350
[ 269.225710] .......(call trace)
[ 269.225713] [<ffffffff81517325>] page_fault+0x25/0x30
[ 269.225716] Task in /1/2 killed as a result of limit of /1
[ 269.225718] memory: usage 511732kB, limit 512000kB, failcnt 5071
[ 269.225720] memory+swap: usage 563200kB, limit 563200kB, failcnt 57
[ 269.225721] kmem: usage 0kB, limit 9007199254740991kB, failcnt 0
[ 269.225722] Memory cgroup stats:cache:8KB rss:511724KB mapped_file:4KB swap:51468KB inactive_anon:265864KB active_anon:245832KB inactive_file:0KB active_file:0KB unevictable:0KB
[ 269.225741] [ pid ] uid tgid total_vm rss nr_ptes swapents oom_score_adj name
[ 269.225757] [ 4554] 0 4554 16626 473 17 25 0 bash
[ 269.225759] [ 4611] 0 4611 103328 90231 208 12260 0 mal
[ 269.225762] [ 4616] 0 4616 103328 32799 88 7562 0 mal
[ 269.225764] Memory cgroup out of memory: Kill process 4611 (mal) score 699 or sacrifice child
[ 269.225766] Killed process 4611 (mal) total-vm:413312kB, anon-rss:360632kB, file-rss:292kB

This version provides more pointed info for memcg in "Memory cgroup stats" section.

Change log:
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>
---
mm/memcontrol.c | 41 +++++++++++++++++++++++++++++++----------
mm/oom_kill.c | 6 ++++--
2 files changed, 35 insertions(+), 12 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 0eab7d5..17317fa 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -118,6 +118,14 @@ 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
@@ -1501,8 +1509,8 @@ 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.
* @memcg: The memory cgroup that went over limit
* @p: Task that is going to be killed
*
@@ -1520,8 +1528,10 @@ 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 *mi;
+ unsigned int i;

- if (!memcg || !p)
+ if (!p)
return;

rcu_read_lock();
@@ -1569,6 +1579,25 @@ 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));
+
+ printk(KERN_INFO "Memory cgroup stats:");
+ for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
+ long long val = 0;
+ if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account)
+ continue;
+ for_each_mem_cgroup_tree(mi, memcg)
+ val += mem_cgroup_read_stat(mi, i);
+ printk(KERN_CONT "%s:%lldKB ", mem_cgroup_stat_names[i], K(val));
+ }
+
+ for (i = 0; i < NR_LRU_LISTS; i++) {
+ unsigned long long val = 0;
+
+ for_each_mem_cgroup_tree(mi, memcg)
+ val += mem_cgroup_nr_lru_pages(mi, BIT(i));
+ printk(KERN_CONT "%s:%lluKB ", mem_cgroup_lru_names[i], K(val));
+ }
+ printk(KERN_CONT "\n");
}

/*
@@ -5195,14 +5224,6 @@ 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);
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 7e9e911..4b8a6dd 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -421,8 +421,10 @@ 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);
}
--
1.7.6.1

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