The following is a demonstration of the vmbypid.d command,

   # vmbypid.d 
   Tracing... Hit Ctrl-C to end.
   ^C
               EXEC      PID                     VM    VALUE
               find    19216             prot_fault        1
               bash    19216                   zfod        1
             dtrace    19215                 pgfrec        3
             dtrace    19215                  pgrec        3
               bash    19216                 pgfrec        5
               bash    19216                  pgrec        5
               find    19216              cow_fault        6
               find    19216                 pgfrec        6
               find    19216                  pgrec        6
               bash    19216             prot_fault       10
               bash    19216              cow_fault       15
               bash    19155             prot_fault       30
             dtrace    19215                   zfod       52
               find    19216                   zfod       54
             dtrace    19215               as_fault       56
               bash    19216               as_fault       74
               find    19216               as_fault       91
               find    19216                 fspgin      315
               find    19216                   pgin      315
               find    19216                 pgpgin      315
               find    19216              maj_fault      315

In the above output, the find command at PID 19211 triggered 315 maj_faults -
major faults, that would require disk activity to satisfy (as confirmed by the
pgpgin value for pages paged in).