Re: [Bug 192981] New: page allocation stalls

[Alexander Polakov <apolyakov@beget.ru>]

On 01/24/2017 12:51 AM, Andrew Morton wrote:

Tetsuo Handa suggested applying kmallocwd patch 
(http://lkml.kernel.org/r/1478416501-10104-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp)
and sending netconsole logs to this list.

I uploaded them here: http://aplkv.beget.tech/lkml/

>
>
> (switched to email.  Please respond via emailed reply-to-all, not via the
> bugzilla web interface).
>
> A 2100 second page allocation stall!
>
>
> On Fri, 20 Jan 2017 15:14:13 +0000 bugzilla-daemon@bugzilla.kernel.org wrote:
>
>> https://bugzilla.kernel.org/show_bug.cgi?id=192981
>>
>>             Bug ID: 192981
>>            Summary: page allocation stalls
>>            Product: Memory Management
>>            Version: 2.5
>>     Kernel Version: 4.9
>>           Hardware: x86-64
>>                 OS: Linux
>>               Tree: Mainline
>>             Status: NEW
>>           Severity: normal
>>           Priority: P1
>>          Component: Page Allocator
>>           Assignee: akpm@linux-foundation.org
>>           Reporter: apolyakov@beget.ru
>>         Regression: No
>>
>> Created attachment 252621
>>   --> https://bugzilla.kernel.org/attachment.cgi?id=252621&action=edit
>> netconsole log with page allocation stalls
>>
>> We have been experiencing page allocation stalls regularly on our machines used
>> as backup servers (many disks, mostly running rsync and rm).
>>
>> A notable one (2102516ms):
>>
>> 2017-01-17T11:08:33.754562+03:00 storage8 [335170.452601] rsync:
>> 2017-01-17T11:08:33.754574+03:00 page allocation stalls for 2102516ms, order:0
>> 2017-01-17T11:08:33.754825+03:00 storage8 ,
>> mode:0x26040d0(GFP_TEMPORARY|__GFP_COMP|__GFP_NOTRACK)
>> 2017-01-17T11:08:33.755094+03:00 storage8 [335170.452896] CPU: 2 PID: 20383
>> Comm: rsync Tainted: G           O    4.9.0-0-beget-vanilla #1
>> 2017-01-17T11:08:33.755337+03:00 storage8 [335170.453156] Hardware name:
>> Supermicro X8DTL/X8DTL, BIOS 2.1b       11/16/2012
>> 2017-01-17T11:08:33.755379+03:00 storage8 [335170.453414]  0000000000000000
>> 2017-01-17T11:08:33.755379+03:00 storage8  ffffffff92441e0b
>> 2017-01-17T11:08:33.755393+03:00 storage8  ffff8c4b0f30f430
>> 2017-01-17T11:08:33.755484+03:00 storage8  0000000000000001
>> 2017-01-17T11:08:33.755600+03:00 storage8
>> 2017-01-17T11:08:33.755603+03:00 storage8 [335170.453681]  ffffffff92c3d1f8
>> 2017-01-17T11:08:33.755643+03:00 storage8  ffffffff92189594
>> 2017-01-17T11:08:33.755648+03:00 storage8  ffff8c4b0f315088
>> 2017-01-17T11:08:33.755754+03:00 storage8  026040d0026040d0
>> 2017-01-17T11:08:33.755874+03:00 storage8
>> 2017-01-17T11:08:33.755874+03:00 storage8 [335170.453951]  0000000000000020
>> 2017-01-17T11:08:33.755880+03:00 storage8  0000000000000010
>> 2017-01-17T11:08:33.755913+03:00 storage8  ffffa449d15cb7f8
>> 2017-01-17T11:08:33.756024+03:00 storage8  ffffa449d15cb7a8
>> 2017-01-17T11:08:33.756163+03:00 storage8
>> 2017-01-17T11:08:33.756278+03:00 storage8 [335170.454216] Call Trace:
>> 2017-01-17T11:08:33.756401+03:00 storage8 [335170.454347]  [<ffffffff92441e0b>]
>> ? dump_stack+0x47/0x5c
>> 2017-01-17T11:08:33.756537+03:00 storage8 [335170.454479]  [<ffffffff92189594>]
>> ? warn_alloc+0x134/0x150
>> 2017-01-17T11:08:33.756677+03:00 storage8 [335170.454612]  [<ffffffff92189f2d>]
>> ? __alloc_pages_nodemask+0x90d/0xdb0
>> 2017-01-17T11:08:33.756808+03:00 storage8 [335170.454753]  [<ffffffff923a5da4>]
>> ? _xfs_trans_bjoin+0xe4/0x110
>> 2017-01-17T11:08:33.756955+03:00 storage8 [335170.454892]  [<ffffffff921d76fa>]
>> ? alloc_pages_current+0x9a/0x120
>> 2017-01-17T11:08:33.757096+03:00 storage8 [335170.455027]  [<ffffffff921de440>]
>> ? new_slab+0x550/0x5f0
>> 2017-01-17T11:08:33.757218+03:00 storage8 [335170.455162]  [<ffffffff921df2eb>]
>> ? ___slab_alloc.isra.59+0x3db/0x500
>> 2017-01-17T11:08:33.757346+03:00 storage8 [335170.455297]  [<ffffffff923a683a>]
>> ? xfs_trans_brelse+0x1aa/0x270
>> 2017-01-17T11:08:33.757489+03:00 storage8 [335170.455427]  [<ffffffff921f4612>]
>> ? memcg_kmem_get_cache+0x72/0x170
>> 2017-01-17T11:08:33.757632+03:00 storage8 [335170.455567]  [<ffffffff92447837>]
>> ? __radix_tree_create+0xa7/0x320
>> 2017-01-17T11:08:33.757762+03:00 storage8 [335170.455706]  [<ffffffff92200be5>]
>> ? __slab_alloc.isra.60+0xe/0x12
>> 2017-01-17T11:08:33.757897+03:00 storage8 [335170.455842]  [<ffffffff921df5b0>]
>> ? kmem_cache_alloc+0x1a0/0x1b0
>> 2017-01-17T11:08:33.758034+03:00 storage8 [335170.455978]  [<ffffffff9221b746>]
>> ? __d_alloc+0x26/0x1c0
>> 2017-01-17T11:08:33.758160+03:00 storage8 [335170.456108]  [<ffffffff9221bb67>]
>> ? d_alloc+0x17/0x80
>> 2017-01-17T11:08:33.758290+03:00 storage8 [335170.456236]  [<ffffffff9221bdf1>]
>> ? d_alloc_parallel+0x31/0x4b0
>> 2017-01-17T11:08:33.758429+03:00 storage8 [335170.456370]  [<ffffffff9220f836>]
>> ? lookup_fast+0x56/0x2f0
>> 2017-01-17T11:08:33.758579+03:00 storage8 [335170.456505]  [<ffffffff923804de>]
>> ? xfs_iunlock+0x17e/0x210
>> 2017-01-17T11:08:33.758694+03:00 storage8 [335170.456635]  [<ffffffff922237f2>]
>> ? legitimize_mnt+0x12/0x40
>> 2017-01-17T11:08:33.758818+03:00 storage8 [335170.456770]  [<ffffffff9220d8f0>]
>> ? lookup_slow+0x80/0x170
>> 2017-01-17T11:08:33.758955+03:00 storage8 [335170.456897]  [<ffffffff9220fd08>]
>> ? walk_component+0x1a8/0x270
>> 2017-01-17T11:08:33.759086+03:00 storage8 [335170.457024]  [<ffffffff92210398>]
>> ? path_lookupat+0x48/0xf0
>> 2017-01-17T11:08:33.759200+03:00 storage8 [335170.457153]  [<ffffffff92212e75>]
>> ? filename_lookup+0xb5/0x190
>> 2017-01-17T11:08:33.759336+03:00 storage8 [335170.457282]  [<ffffffff92474992>]
>> ? strncpy_from_user+0x42/0x140
>> 2017-01-17T11:08:33.759462+03:00 storage8 [335170.457411]  [<ffffffff9221305b>]
>> ? getname_flags+0x7b/0x200
>> 2017-01-17T11:08:33.759593+03:00 storage8 [335170.457538]  [<ffffffff92208b66>]
>> ? vfs_fstatat+0x46/0x90
>> 2017-01-17T11:08:33.759719+03:00 storage8 [335170.457666]  [<ffffffff9221aaf4>]
>> ? dput+0x34/0x200
>> 2017-01-17T11:08:33.759859+03:00 storage8 [335170.457793]  [<ffffffff92208d47>]
>> ? SyS_newlstat+0x17/0x30
>> 2017-01-17T11:08:33.759977+03:00 storage8 [335170.457923]  [<ffffffff9282b7a0>]
>> ? entry_SYSCALL_64_fastpath+0x13/0x94
>>
>>
>> # sysctl vm
>> vm.admin_reserve_kbytes = 1048576
>> vm.block_dump = 0
>> error: permission denied on key 'vm.compact_memory'
>> vm.compact_unevictable_allowed = 1
>> vm.dirty_background_bytes = 0
>> vm.dirty_background_ratio = 1
>> vm.dirty_bytes = 0
>> vm.dirty_expire_centisecs = 1000
>> vm.dirty_ratio = 1
>> vm.dirty_writeback_centisecs = 100
>> vm.dirtytime_expire_seconds = 43200
>> vm.drop_caches = 0
>> vm.extfrag_threshold = 500
>> vm.hugepages_treat_as_movable = 0
>> vm.hugetlb_shm_group = 0
>> vm.laptop_mode = 0
>> vm.legacy_va_layout = 0
>> vm.lowmem_reserve_ratio = 128   128     16
>> vm.max_map_count = 65530
>> vm.memory_failure_early_kill = 0
>> vm.memory_failure_recovery = 1
>> vm.min_free_kbytes = 4194304
>> vm.min_slab_ratio = 1
>> vm.min_unmapped_ratio = 1
>> vm.mmap_min_addr = 65536
>> vm.mmap_rnd_bits = 28
>> vm.nr_hugepages = 0
>> vm.nr_hugepages_mempolicy = 0
>> vm.nr_overcommit_hugepages = 0
>> vm.nr_pdflush_threads = 0
>> vm.numa_zonelist_order = default
>> vm.oom_dump_tasks = 1
>> vm.oom_kill_allocating_task = 0
>> vm.overcommit_kbytes = 0
>> vm.overcommit_memory = 1
>> vm.overcommit_ratio = 50
>> vm.page-cluster = 3
>> vm.panic_on_oom = 0
>> vm.percpu_pagelist_fraction = 0
>> vm.stat_interval = 1
>> error: permission denied on key 'vm.stat_refresh'
>> vm.swappiness = 0
>> vm.user_reserve_kbytes = 131072
>> vm.vfs_cache_pressure = 200
>> vm.watermark_scale_factor = 100
>> vm.zone_reclaim_mode = 7
>>
>> # free -m
>>              total       used       free     shared    buffers     cached
>> Mem:         96646      46330      50315          0      25529       1228
>> -/+ buffers/cache:      19572      77073
>> Swap:            0          0          0
>>
>> (Yes, we don't have any swap configured)
>>
>> On this particular one we have 56 disks, using both XFS and EXT4. I attach full
>> netconsole log for 18/01/2017. You can see there that we run drop_caches
>> regularly as it helps to keep the machine alive.
>>
>> Since then we've also tried mounting filesystems with sync flag to avoid
>> writeback and it seems to have helped a lot (full day without stalls).
>>
>> --
>> You are receiving this mail because:
>> You are the assignee for the bug.

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