taglinefilesource code
shm_dtime12include/linux/shm.htime_t  shm_dtime;    /* last detach time */
shm_dtime120ipc/shm.cshp->shm_atime = shp->shm_dtime = 0;
shm_dtime272ipc/shm.ctbuf.shm_dtime  = shp->shm_dtime;
shm_dtime317ipc/shm.ctbuf.shm_dtime  = shp->shm_dtime;
shm_dtime581ipc/shm.cshp->shm_dtime = CURRENT_TIME;