[LU-4148] Clients experiencing massive watchdogs in mdtest rmdir

• Type: Bug
• Resolution: Cannot Reproduce
• Priority: Major
• Affects Version/s: Lustre 2.5.0
• Environment: Hyperion/LLNL
• Severity: 3
• Assignee: Lai Siyao
• Reporter: Cliff White (Inactive)

Description

Running mdtest, seeing a performance drop in rmdir.
All clients appear to be hitting watchdogs, example:

INFO: task mdtest:7072 blocked for more than 120 seconds.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
mdtest        D 0000000000000009     0  7072   7058 0x00000000
 ffff880870771e08 0000000000000082 ffff880871506aa0 ffff880871506aa0
 ffff880871506aa0 000000000000000b ffff880871506aa0 0000001081065d54
 ffff880871507058 ffff880870771fd8 000000000000fb88 ffff880871507058
Call Trace:
 [<ffffffff8118f541>] ? path_put+0x31/0x40
 [<ffffffff8150f78e>] __mutex_lock_slowpath+0x13e/0x180
 [<ffffffff8150f62b>] mutex_lock+0x2b/0x50
 [<ffffffff81192367>] do_rmdir+0xb7/0x120
 [<ffffffff8100c535>] ? math_state_restore+0x45/0x60
 [<ffffffff81192426>] sys_rmdir+0x16/0x20
 [<ffffffff8100b072>] system_call_fastpath+0x16/0x1b

No errors on MDS