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@xxxxxxxxxxxxxxxxxxx)
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@xxxxxxxxxxxxxxxxxxx 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@xxxxxxxxxxxxxxxxxxxx
Reporter: apolyakov@xxxxxxxx
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).
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