High latency from excessive SMB TRIM operations

• Extremely high CIFS latency, particularly for "other" operations
• High number of ioctl_fsctl_file_level_trim_ops with extremely high latency.

::*> statistics show-periodic -object smb2 -instance svmtest -counter ioctl_fsctl_file_level_trim_ops|ioctl_fsctl_file_level_trim_latency
cluster: smb2.svmtest: 10/19/2020 15:23:25
 ioctl_fsctl_file_level ioctl_fsctl_file_level
                   trim                   trim
                latency                    ops
 ---------------------- ----------------------
             50854.31us                1385.47
             52302.41us                1318.84
             53776.76us                1484.94
             55285.58us                1387.76             
             56934.23us                1323.12

• High CPU contention, denoted by the wafl msg latency. 
  • Values greater than 1ms, could indicate CPU contention 

::*> statistics show-periodic -object wafl -counter avg_wafl_msg_latency -node node_1 -instance wafl
cluster1: wafl.wafl: 10/16/2020 18:25:28
 avg_wafl
      msg    Complete    Number of
  latency Aggregation Constituents
 -------- ----------- ------------
  14.91ms      n/a      n/a
  23.25ms      n/a      n/a
  19.72ms      n/a      n/a
  17.34ms      n/a      n/a
  19.09ms      n/a      n/a