FYI, we noticed the below changes on

git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
commit cc87317726f851531ae8422e0c2d3d6e2d7b1955 ("mm: page_alloc: revert inadvertent !__GFP_FS retry behavior change")

Before the commit, the page allocation failure is as follow (in prev_dmesg).

[    3.069031] BTRFS: selftest: Running space stealing from bitmap to extent
[    3.070243] BTRFS: selftest: Free space cache tests finished
[    3.070919] BTRFS: selftest: Running extent buffer operation tests
[    3.072111] BTRFS: selftest: Running btrfs_split_item tests
[    3.072840] BTRFS: selftest: Running find delalloc tests
[    3.295788] swapper/0: page allocation failure: order:0, mode:0x50
[    3.296315] CPU: 0 PID: 1 Comm: swapper/0 Tainted: G        W       4.0.0-rc1-00038-g39afb5e #4
[    3.297033] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[    3.297490]  00000000 00000000 4002bdd4 4158716c 00000001 4002bdfc 410c64f1 41719e60
[    3.298218]  4001b304 00000000 00000050 4002bdf8 4158da0d 00000000 00000000 4002be80
[    3.298929]  410c8331 00000050 00000000 00000000 00000001 00000050 4001b000 00000040
[    3.299644] Call Trace:
[    3.299859]  [<4158716c>] dump_stack+0x48/0x60
[    3.300235]  [<410c64f1>] warn_alloc_failed+0xa1/0xe0
[    3.300640]  [<4158da0d>] ? _raw_spin_unlock+0x1d/0x30
[    3.301070]  [<410c8331>] __alloc_pages_nodemask+0x4d1/0x810
[    3.301517]  [<410c04e3>] pagecache_get_page+0xf3/0x1c0
[    3.301957]  [<4124ccf7>] btrfs_test_extent_io+0x67/0x660
[    3.302401]  [<4124c5cb>] ? btrfs_test_extent_buffer_operations+0x54b/0x6c0
[    3.302966]  [<4184109b>] ? debugfs_init+0x4e/0x4e
[    3.303360]  [<41841192>] init_btrfs_fs+0xf7/0x172
[    3.303750]  [<41000472>] do_one_initcall+0xc2/0x1c0
[    3.304155]  [<41829462>] ? repair_env_string+0x12/0x54
[    3.304566]  [<41829400>] ? do_early_param+0x23/0x73
[    3.304971]  [<4104ca99>] ? parse_args+0x249/0x4e0
[    3.305364]  [<41829450>] ? do_early_param+0x73/0x73
[    3.305767]  [<41829bce>] kernel_init_freeable+0xe3/0x160
[    3.306204]  [<41829bce>] ? kernel_init_freeable+0xe3/0x160
[    3.306632]  [<41582b78>] kernel_init+0x8/0xc0
[    3.307022]  [<4158e281>] ret_from_kernel_thread+0x21/0x30
[    3.307455]  [<41582b70>] ? rest_init+0xb0/0xb0
[    3.307826] Mem-Info:
[    3.308024] Normal per-cpu:
[    3.308251] CPU    0: hi:   90, btch:  15 usd:  82
[    3.308630] CPU    1: hi:   90, btch:  15 usd:   2
[    3.309026] active_anon:0 inactive_anon:0 isolated_anon:0
[    3.309026]  active_file:873 inactive_file:62554 isolated_file:0
[    3.309026]  unevictable:9425 dirty:0 writeback:0 unstable:0
[    3.309026]  free:539 slab_reclaimable:0 slab_unreclaimable:0
[    3.309026]  mapped:0 shmem:0 pagetables:0 bounce:0
[    3.309026]  free_cma:0


After the commit, the system hang at the same position (in .dmesg).

[    3.303002] BTRFS: selftest: Running btrfs free space cache tests
[    3.303636] BTRFS: selftest: Running extent only tests
[    3.304190] BTRFS: selftest: Running bitmap only tests
[    3.304726] BTRFS: selftest: Running bitmap and extent tests
[    3.305346] BTRFS: selftest: Running space stealing from bitmap to extent
[    3.306318] BTRFS: selftest: Free space cache tests finished
[    3.306881] BTRFS: selftest: Running extent buffer operation tests
[    3.307483] BTRFS: selftest: Running btrfs_split_item tests
[    3.308134] BTRFS: selftest: Running find delalloc tests

BUG: kernel boot hang
Elapsed time: 305


Thanks,
Ying Huang