fs_fill in ubuntu_ltp/fs tend to timeout on ARM64 node wright-kernel

[Po-Hsu Lin]

This issue can be found on ARM64 node wright-kernel.

Despite of bumping the timeout to 2h10m, the fs_fill test still can be found failing with timeout on this 96 core ARM64 system.

The last filesystem being tested is btrfs:
INFO: Test start time: Wed Jun 5 04:11:36 UTC 2024
COMMAND: /opt/ltp/bin/ltp-pan -q -e -S -a 71227 -n 71227 -f /tmp/ltp-HmCwV9AlxO/alltests -l /dev/null -C /dev/null -T /dev/null
LOG File: /dev/null
FAILED COMMAND File: /dev/null
TCONF COMMAND File: /dev/null
Running tests.......
tst_device.c:96: TINFO: Found free device 3 '/dev/loop3'
tst_test.c:1741: TINFO: LTP version: 20230929-407-g58aa31f55
tst_test.c:1625: TINFO: Timeout per run is 2h 10m 00s
...
tst_test.c:1701: TINFO: === Testing on btrfs ===
tst_test.c:1117: TINFO: Formatting /dev/loop3 with btrfs opts='' extra opts=''
tst_test.c:1131: TINFO: Mounting /dev/loop3 to /tmp/ltp-HmCwV9AlxO/LTP_fs_fDrfnj/mntpoint fstyp=btrfs flags=0
fs_fill.c:115: TINFO: Running 98 writer threads
tst_fill_fs.c:127: TINFO: writev("mntpoint/subdir/thread38/AOF", iov, 512): ENOSPC
tst_fill_fs.c:127: TINFO: writev("mntpoint/subdir/thread40/AOF", iov, 512): ENOSPC
tst_fill_fs.c:127: TINFO: writev("mntpoint/subdir/thread24/AOF", iov, 512): ENOSPC
...
tst_fill_fs.c:36: TINFO: Creating file mntpoint/subdir/thread68/file3 size 49753678
tst_fill_fs.c:36: TINFO: Creating file mntpoint/subdir/thread30/file3 size 88520105
Test timeouted, sending SIGKILL!
tst_test.c:1679: TINFO: If you are running on slow machine, try exporting LTP_TIMEOUT_MUL > 1
tst_test.c:1681: TBROK: Test killed! (timeout?)

Summary:
passed 9
failed 0
broken 1
skipped 0
warnings 0
INFO: ltp-pan reported some tests FAIL
LTP Version: 20230929-407-g58aa31f55
INFO: Test end time: Wed Jun 5 06:31:29 UTC 2024
06/05 06:31:30 INFO |ubuntu_ltp:0145| Restore timeout multiplier LTP_TIMEOUT_MUL back to default

This happens after the LTP fork update in March.
https://lists.ubuntu.com/archives/kernel-team/2024-March/149664.html

Here are the test results on node wright-kernel:
  * B-hwe-5.4.0-186.206~18.04.1 - TBROK: failed: ENOSPC on btrfs
  * F-hwe-5.15.0-112.122~20.04.1 - retesting
  * J-lowlatency-5.15.0-110.120 - Timeout
  * J-hwe-6.5.0-34.34~22.04.2 - Timeout