/usr/src/sys/ufs/ffs/ffs_vfsops.c
1159 if (((ump->um_flags) & UM_CANDELETE) != 0) {
1160 ump->um_trim_tq = taskqueue_create("trim", M_WAITOK,
1161 taskqueue_thread_enqueue, &ump->um_trim_tq);
1162 taskqueue_start_threads(&ump->um_trim_tq, 1, PVFS,
1163 "%s trim", mp->mnt_stat.f_mntonname);
1164 ump->um_trimhash = hashinit(MAXTRIMIO, M_TRIM,
1165 &ump->um_trimlisthashsize);
# ps xH|grep trim
0 - DLs 0:00,03 [kernel// trim]
0 - DLs 0:15,91 [kernel//usr trim]
0 - DLs 0:00,45 [kernel//usr/obj trim]
0 - DLs 0:00,83 [kernel//cachefs trim]