Re: [mm, page_alloc] d0164adc89: -100.0% fsmark.app_overhead

[Huang, Ying <ying.huang@linux.intel.com>]

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Mel Gorman <mgorman@techsingularity.net> writes:

> On Fri, Nov 27, 2015 at 09:14:52AM +0800, Huang, Ying wrote:
>> Hi, Mel,
>> 
>> Mel Gorman <mgorman@techsingularity.net> writes:
>> 
>> > On Thu, Nov 26, 2015 at 08:56:12AM +0800, kernel test robot wrote:
>> >> FYI, we noticed the below changes on
>> >> 
>> >> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
>> >> commit d0164adc89f6bb374d304ffcc375c6d2652fe67d ("mm, page_alloc:
>> >> distinguish between being unable to sleep, unwilling to sleep and
>> >> avoiding waking kswapd")
>> >> 
>> >> Note: the testing machine is a virtual machine with only 1G memory.
>> >> 
>> >
>> > I'm not actually seeing any problem here. Is this a positive report or
>> > am I missing something obvious?
>> 
>> Sorry the email subject is generated automatically and I forget to
>> change it to some meaningful stuff before sending out.  From the testing
>> result, we found the commit make the OOM possibility increased from 0%
>> to 100% on this machine with small memory.  I also added proc-vmstat
>> information data too to help diagnose it.
>> 
>
> There is no reference to OOM possibility in the email that I can see. Can
> you give examples of the OOM messages that shows the problem sites? It was
> suspected that there may be some callers that were accidentally depending
> on access to emergency reserves. If so, either they need to be fixed (if
> the case is extremely rare) or a small reserve will have to be created
> for callers that are not high priority but still cannot reclaim.
>
> Note that I'm travelling a lot over the next two weeks so I'll be slow to
> respond but I will get to it.

Here is the kernel log,  the full dmesg is attached too.  The OOM
occurs during fsmark testing.

Best Regards,
Huang, Ying

[   31.453514] kworker/u4:0: page allocation failure: order:0, mode:0x2200000
[   31.463570] CPU: 0 PID: 6 Comm: kworker/u4:0 Not tainted 4.3.0-08056-gd0164ad #1
[   31.466115] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014
[   31.477146] Workqueue: writeback wb_workfn (flush-253:0)
[   31.481450]  0000000000000000 ffff880035ac75e8 ffffffff8140a142 0000000002200000
[   31.492582]  ffff880035ac7670 ffffffff8117117b ffff880037586b28 ffff880000000040
[   31.507631]  ffff88003523b270 0000000000000040 ffff880035abc800 ffffffff00000000
[   31.510568] Call Trace:
[   31.511828]  [<ffffffff8140a142>] dump_stack+0x4b/0x69
[   31.513391]  [<ffffffff8117117b>] warn_alloc_failed+0xdb/0x140
[   31.523163]  [<ffffffff81174ec4>] __alloc_pages_nodemask+0x874/0xa60
[   31.524949]  [<ffffffff811bcb62>] alloc_pages_current+0x92/0x120
[   31.526659]  [<ffffffff811c73e4>] new_slab+0x3d4/0x480
[   31.536134]  [<ffffffff811c7c36>] __slab_alloc+0x376/0x470
[   31.537541]  [<ffffffff814e0ced>] ? alloc_indirect+0x1d/0x50
[   31.543268]  [<ffffffff81338221>] ? xfs_submit_ioend_bio+0x31/0x40
[   31.545104]  [<ffffffff814e0ced>] ? alloc_indirect+0x1d/0x50
[   31.546982]  [<ffffffff811c8e8d>] __kmalloc+0x20d/0x260
[   31.548334]  [<ffffffff814e0ced>] alloc_indirect+0x1d/0x50
[   31.549805]  [<ffffffff814e0fec>] virtqueue_add_sgs+0x2cc/0x3a0
[   31.555396]  [<ffffffff81573a30>] __virtblk_add_req+0xb0/0x1f0
[   31.556846]  [<ffffffff8117a121>] ? pagevec_lookup_tag+0x21/0x30
[   31.558318]  [<ffffffff813e5d72>] ? blk_rq_map_sg+0x1e2/0x4f0
[   31.563880]  [<ffffffff81573c82>] virtio_queue_rq+0x112/0x280
[   31.565307]  [<ffffffff813e9de7>] __blk_mq_run_hw_queue+0x1d7/0x370
[   31.571005]  [<ffffffff813e9bef>] blk_mq_run_hw_queue+0x9f/0xc0
[   31.572472]  [<ffffffff813eb10a>] blk_mq_insert_requests+0xfa/0x1a0
[   31.573982]  [<ffffffff813ebdb3>] blk_mq_flush_plug_list+0x123/0x140
[   31.583686]  [<ffffffff813e1777>] blk_flush_plug_list+0xa7/0x200
[   31.585138]  [<ffffffff813e1c49>] blk_finish_plug+0x29/0x40
[   31.586542]  [<ffffffff81215f85>] wb_writeback+0x185/0x2c0
[   31.592429]  [<ffffffff812166a5>] wb_workfn+0xf5/0x390
[   31.594037]  [<ffffffff81091297>] process_one_work+0x157/0x420
[   31.599804]  [<ffffffff81091ef9>] worker_thread+0x69/0x4a0
[   31.601484]  [<ffffffff81091e90>] ? rescuer_thread+0x380/0x380
[   31.611368]  [<ffffffff8109746f>] kthread+0xef/0x110
[   31.612953]  [<ffffffff81097380>] ? kthread_park+0x60/0x60
[   31.619418]  [<ffffffff818bce8f>] ret_from_fork+0x3f/0x70
[   31.621221]  [<ffffffff81097380>] ? kthread_park+0x60/0x60
[   31.635226] Mem-Info:
[   31.636569] active_anon:4942 inactive_anon:1643 isolated_anon:0
[   31.636569]  active_file:23196 inactive_file:110131 isolated_file:251
[   31.636569]  unevictable:92329 dirty:2865 writeback:1925 unstable:0
[   31.636569]  slab_reclaimable:10588 slab_unreclaimable:3390
[   31.636569]  mapped:2848 shmem:1687 pagetables:876 bounce:0
[   31.636569]  free:1932 free_pcp:218 free_cma:0
[   31.667096] Node 0 DMA free:3948kB min:60kB low:72kB high:88kB active_anon:264kB inactive_anon:128kB active_file:1544kB inactive_file:5296kB unevictable:3136kB isolated(anon):0kB isolated(file):236kB present:15992kB managed:15908kB mlocked:0kB dirty:0kB writeback:0kB mapped:440kB shmem:128kB slab_reclaimable:588kB slab_unreclaimable:304kB kernel_stack:112kB pagetables:80kB unstable:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB writeback_tmp:0kB pages_scanned:3376 all_unreclaimable? no
[   31.708140] lowmem_reserve[]: 0 972 972 972
[   31.710104] Node 0 DMA32 free:3780kB min:3824kB low:4780kB high:5736kB active_anon:19504kB inactive_anon:6444kB active_file:91240kB inactive_file:435228kB unevictable:366180kB isolated(anon):0kB isolated(file):768kB present:1032064kB managed:997532kB mlocked:0kB dirty:11460kB writeback:7700kB mapped:10952kB shmem:6620kB slab_reclaimable:41764kB slab_unreclaimable:13256kB kernel_stack:2752kB pagetables:3424kB unstable:0kB bounce:0kB free_pcp:872kB local_pcp:232kB free_cma:0kB writeback_tmp:0kB pages_scanned:140404 all_unreclaimable? no
[   31.743737] lowmem_reserve[]: 0 0 0 0
[   31.745320] Node 0 DMA: 7*4kB (UME) 2*8kB (UM) 2*16kB (ME) 1*32kB (E) 0*64kB 2*128kB (ME) 2*256kB (ME) 2*512kB (UM) 2*1024kB (ME) 0*2048kB 0*4096kB = 3948kB
[   31.757513] Node 0 DMA32: 1*4kB (U) 0*8kB 4*16kB (UME) 3*32kB (UE) 3*64kB (UM) 1*128kB (U) 1*256kB (U) 0*512kB 3*1024kB (UME) 0*2048kB 0*4096kB = 3812kB
[   31.766470] Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=2048kB
[   31.772953] 227608 total pagecache pages
[   31.774127] 0 pages in swap cache
[   31.775428] Swap cache stats: add 0, delete 0, find 0/0
[   31.776785] Free swap  = 0kB
[   31.777799] Total swap = 0kB
[   31.779569] 262014 pages RAM
[   31.780584] 0 pages HighMem/MovableOnly
[   31.781744] 8654 pages reserved
[   31.790944] 0 pages hwpoisoned
[   31.792008] SLUB: Unable to allocate memory on node -1 (gfp=0x2080000)
[   31.793537]   cache: kmalloc-128, object size: 128, buffer size: 128, default order: 0, min order: 0
[   31.796088]   node 0: slabs: 27, objs: 864, free: 0


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