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Date:   Thu, 22 Nov 2018 14:38:04 +0100
From:   Michal Hocko <mhocko@kernel.org>
To:     ufo19890607@gmail.com
Cc:     akpm@linux-foundation.org, rientjes@google.com,
        kirill.shutemov@linux.intel.com, aarcange@redhat.com,
        penguin-kernel@i-love.sakura.ne.jp, guro@fb.com,
        yang.s@alibaba-inc.com, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, yuzhoujian@didichuxing.com
Subject: Re: [PATCH v15 1/2] Reorganize the oom report in dump_header
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On Wed 21-11-18 19:29:58, ufo19890607@gmail.com wrote:
> From: yuzhoujian <yuzhoujian@didichuxing.com>
> 
> OOM report contains several sections. The first one is the allocation
> context that has triggered the OOM. Then we have cpuset context
> followed by the stack trace of the OOM path. The tird one is the OOM
> memory information. Followed by the current memory state of all system
> tasks. At last, we will show oom eligible tasks and the information
> about the chosen oom victim.
> 
> One thing that makes parsing more awkward than necessary is that we do
> not have a single and easily parsable line about the oom context. This
> patch is reorganizing the oom report to
> 1) who invoked oom and what was the allocation request
> [  515.902945] tuned invoked oom-killer: gfp_mask=0x6200ca(GFP_HIGHUSER_MOVABLE), order=0, oom_score_adj=0
> 
> 2) OOM stack trace
> [  515.904273] CPU: 24 PID: 1809 Comm: tuned Not tainted 4.20.0-rc3+ #3
> [  515.905518] Hardware name: Inspur SA5212M4/YZMB-00370-107, BIOS 4.1.10 11/14/2016
> [  515.906821] Call Trace:
> [  515.908062]  dump_stack+0x5a/0x73
> [  515.909311]  dump_header+0x55/0x28c
> [  515.914260]  oom_kill_process+0x2d8/0x300
> [  515.916708]  out_of_memory+0x145/0x4a0
> [  515.917932]  __alloc_pages_slowpath+0x7d2/0xa16
> [  515.919157]  __alloc_pages_nodemask+0x277/0x290
> [  515.920367]  filemap_fault+0x3d0/0x6c0
> [  515.921529]  ? filemap_map_pages+0x2b8/0x420
> [  515.922709]  ext4_filemap_fault+0x2c/0x40 [ext4]
> [  515.923884]  __do_fault+0x20/0x80
> [  515.925032]  __handle_mm_fault+0xbc0/0xe80
> [  515.926195]  handle_mm_fault+0xfa/0x210
> [  515.927357]  __do_page_fault+0x233/0x4c0
> [  515.928506]  do_page_fault+0x32/0x140
> [  515.929646]  ? page_fault+0x8/0x30
> [  515.930770]  page_fault+0x1e/0x30
> 
> 3) OOM memory information
> [  515.958093] Mem-Info:
> [  515.959647] active_anon:26501758 inactive_anon:1179809 isolated_anon:0
>  active_file:4402672 inactive_file:483963 isolated_file:1344
>  unevictable:0 dirty:4886753 writeback:0 unstable:0
>  slab_reclaimable:148442 slab_unreclaimable:18741
>  mapped:1347 shmem:1347 pagetables:58669 bounce:0
>  free:88663 free_pcp:0 free_cma:0
> ...
> 
> 4) current memory state of all system tasks
> [  516.079544] [    744]     0   744     9211     1345   114688       82             0 systemd-journal
> [  516.082034] [    787]     0   787    31764        0   143360       92             0 lvmetad
> [  516.084465] [    792]     0   792    10930        1   110592      208         -1000 systemd-udevd
> [  516.086865] [   1199]     0  1199    13866        0   131072      112         -1000 auditd
> [  516.089190] [   1222]     0  1222    31990        1   110592      157             0 smartd
> [  516.091477] [   1225]     0  1225     4864       85    81920       43             0 irqbalance
> [  516.093712] [   1226]     0  1226    52612        0   258048      426             0 abrtd
> [  516.112128] [   1280]     0  1280   109774       55   299008      400             0 NetworkManager
> [  516.113998] [   1295]     0  1295    28817       37    69632       24             0 ksmtuned
> [  516.144596] [  10718]     0 10718  2622484  1721372 15998976   267219             0 panic
> [  516.145792] [  10719]     0 10719  2622484  1164767  9818112    53576             0 panic
> [  516.146977] [  10720]     0 10720  2622484  1174361  9904128    53709             0 panic
> [  516.148163] [  10721]     0 10721  2622484  1209070 10194944    54824             0 panic
> [  516.149329] [  10722]     0 10722  2622484  1745799 14774272    91138             0 panic
> 
> 5) oom context (contrains and the chosen victim).
> oom-kill:constraint=CONSTRAINT_NONE,nodemask=(null),cpuset=/,mems_allowed=0-1,task=panic,pid=10737,uid=0
> 
> An admin can easily get the full oom context at a single line which
> makes parsing much easier.
> 
> Signed-off-by: yuzhoujian <yuzhoujian@didichuxing.com>

Looks good, finally
Acked-by: Michal Hocko <mhocko@suse.com>
-- 
Michal Hocko
SUSE Labs