Comment 3 for bug 1891773

I'm also getting kcompactd0 hanging on its own on another host, which presumably blocks btrfs-transaction later on:
[606364.285752] INFO: task kcompactd0:27 blocked for more than 120 seconds.
[606364.285994] Not tainted 4.15.0-112-generic #113-Ubuntu
[606364.286129] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[606364.286268] kcompactd0 D 0 27 2 0x80000000
[606364.286270] Call Trace:
[606364.286284] __schedule+0x24e/0x880
[606364.286341] ? btree_releasepage+0x42/0x50 [btrfs]
[606364.286343] schedule+0x2c/0x80
[606364.286344] io_schedule+0x16/0x40
[606364.286345] __lock_page+0xff/0x140
[606364.286347] ? page_cache_tree_insert+0xe0/0xe0
[606364.286348] migrate_pages+0x91f/0xb80
[606364.286349] ? __ClearPageMovable+0x10/0x10
[606364.286350] ? isolate_freepages_block+0x3b0/0x3b0
[606364.286351] compact_zone+0x681/0x950
[606364.286352] kcompactd_do_work+0xfe/0x2a0
[606364.286354] ? __switch_to_asm+0x35/0x70
[606364.286355] ? __switch_to_asm+0x41/0x70
[606364.286356] kcompactd+0x86/0x1c0
[606364.286357] ? kcompactd+0x86/0x1c0
[606364.286358] ? wait_woken+0x80/0x80
[606364.286360] kthread+0x121/0x140
[606364.286361] ? kcompactd_do_work+0x2a0/0x2a0
[606364.286361] ? kthread_create_worker_on_cpu+0x70/0x70
[606364.286363] ret_from_fork+0x35/0x40