I have amused myself by hunting for unused functions in the kernel. While
the biggest offenders have been removed, there are still a lot of unused
stuff in a standard kernel.

Below is the list of unreferenced symbols in the i386 GENERIC kernel (source
CVS:ed an hour ago). Please look through the list to see if something may be
removed/suitable #ifdef:ed in your favourite part of the source.

   /Krister


aarp.o D  aarptab_size
aarp.o T  aarp_clean
ad1848.o T  ad_xwrite
adv.o T  adv_detach
advlib.o T  AscResetDevice
agp.o T  agp_acquire
agp.o T  agp_alloc_memory
agp.o T  agp_bind_memory
agp.o T  agp_enable
agp.o T  agp_find_device
agp.o T  agp_free_gatt
agp.o T  agp_free_memory
agp.o T  agp_get_info
agp.o T  agp_memory_info
agp.o T  agp_release
agp.o T  agp_state
agp.o T  agp_unbind_memory
aic6360.o T  aic_dump6360
aic6360.o T  aic_dump_driver
aic6360.o T  aic_print_active_acb
aic6915.o D  sf_copy_small
aic7xxx.o T  ahc_activate
aic7xxx.o T  ahc_detach
am79c930.o T  am79c930_gcr_read
an.o T  an_shutdown
arc4.o T  arc4_decrypt
auconv.o T  change_sign16_swap_bytes_be
auconv.o T  linear16_to_linear8_be
auconv.o T  linear8_to_linear16_be
auconv.o T  slinear16_to_ulinear8_be
auconv.o T  ulinear8_to_slinear16_be
bha.o T  bha_nextmbi
bha.o T  bha_nextmbo
bha.o T  bha_reset_ccb
bios32.o T  bios32_service
bridgestp.o T  bstp_disable_change_detection
bridgestp.o T  bstp_enable_change_detection
bridgestp.o T  bstp_set_bridge_priority
bridgestp.o T  bstp_set_path_cost
bridgestp.o T  bstp_set_port_priority
bus_machdep.o T  _bus_dmamap_sync
bus_machdep.o T  _i386_memio_map
bus_machdep.o T  _i386_memio_unmap
cd.o T  lba2msf
cd.o T  msf2lba
clnp_debug.o C  clnp_debug
clnp_input.o C  eonstat
clnp_output.o T  clnp_ctloutput
clnp_subr.o T  clnp_ypocb
clock.o T  mc146818_write
clock.o T  sysbeep
cltp_usrreq.o T  cltp_ctlinput
cnmagic.o T  cn_destroy_magic
coda_namecache.o T  coda_nc_name
coda_namecache.o T  coda_nc_zapvnode
coda_subr.o T  coda_debugoff
coda_subr.o T  coda_debugon
coda_venus.o T  venus_read
coda_venus.o T  venus_readdir
coda_venus.o T  venus_write
coda_vfsops.o T  coda_vptofh
coda_vfsops.o T  getNewVnode
coda_vnops.o T  print_cred
cons.o T  cnbell
cons.o T  nullcnpollc
cs89x0.o T  cs_activate
cy82c693.o T  cy82c693_read
cz.o T  cz_reset_board
db_dbgreg.o T  dr0
db_dbgreg.o T  dr1
db_dbgreg.o T  dr2
db_dbgreg.o T  dr3
db_dbgreg.o T  dr6
db_dbgreg.o T  inb
db_dbgreg.o T  inl
db_dbgreg.o T  inw
db_dbgreg.o T  outb
db_dbgreg.o T  outl
db_dbgreg.o T  outw
db_interface.o D  ddb_cpu
db_run.o T  db_single_step
db_sym.o T  db_symstr
db_trace.o T  db_find_trace_symbols
db_variables.o R  db_evars
db_variables.o T  db_set_variable
dp8390.o D  dp8390_debug
eisa_machdep.o T  eisa_conf_read_dma
eisa_machdep.o T  eisa_conf_read_io
eisa_machdep.o T  eisa_conf_read_irq
eisa_machdep.o T  eisa_conf_read_mem
eisa_machdep.o T  eisa_intr_evcnt
eisa_machdep.o T  eisa_mem_alloc
eisa_machdep.o T  eisa_mem_free
elinkxl.o T  ex_activate
elinkxl.o T  ex_detach
elinkxl.o T  ex_printstats
esp_pcmcia.o T  esp_pcmcia_enable
ess.o T  ess_config_addr
fd.o T  fd_dev_to_type
ffs_softdep.o D  debug20
ffs_softdep.o D  debug21
ffs_softdep.o D  debug23
ffs_softdep.o D  debug24
ffs_softdep.o D  debug25
ffs_softdep.o D  debug26
ffs_softdep.o D  debug27
ffs_softdep.o D  debug28
ffs_softdep.o D  debug29
ffs_softdep.o D  debug30
ffs_vnops.o D  doclusterread
ffs_vnops.o D  doclusterwrite
fil.o D  icmptoicmp6unreach
gdt.o T  gdt_alloc_cpu
gus.o T  gus_get_in_gain
gus.o T  gus_get_out_gain
gus.o T  gus_set_in_gain
hd64570.o D  sca_debug
i82365_isa.o D  pcicisa_debug
i82557.o T  fxp_activate
i82557.o T  fxp_detach
ibcs2_exec.o D  ibcs2_debug
if.o T  if_clone_detach
if.o T  ifa_ifwithaf
if_arp.o C  arp_intimer
if_arp.o T  arpioctl
if_bge.o D  bge_swapbits
if_bge.o D  bge_swapindex
if_bge.o T  bge_shutdown
if_bridge.o R  bridge_control_table_size
if_bridge.o T  bridge_ifdetach
if_ec.o T  ec_readmem
if_hippisubr.o T  hippi_ip_input
if_lmc_media.o D  lmc_t1_cables
if_media.o T  ifmedia_list_add
if_spppsubr.o T  sppp_pick
if_strip.o T  strip_timeout
if_wm.o D  wm_copy_small
if_x25subr.o T  x25_dg_rtinit
if_x25subr.o T  x25_ifoutput
if_x25subr.o T  x25_iftimeout
in6.o R  in6addr_linklocal_allrouters
in6.o R  in6mask0
in6.o R  in6mask96
in6.o T  in6_ifawithifp
in6.o T  in6_ifindex2scopeid
in6.o T  in6_is_addr_deprecated
in6_proto.o D  pmtu_probe
in6_src.o T  in6_clearscope
ioconf.o R  amrcf_locnames
ioconf.o R  cardbuscf_locnames
ioconf.o R  cbbuscf_locnames
ioconf.o R  commulticf_locnames
ioconf.o R  cpcbuscf_locnames
ioconf.o R  cpucf_locnames
ioconf.o R  fwbuscf_locnames
ioconf.o R  pciidecf_locnames
ioconf.o R  pckbcportcf_locnames
ioconf.o R  pcmciaslotcf_locnames
ioconf.o R  pnpbioscf_locnames
ioconf.o R  psscf_locnames
ioconf.o R  skgeccf_locnames
ioconf.o R  upccf_locnames
ioconf.o R  vmecf_locnames
ioconf.o R  wsdisplaydevcf_locnames
ioconf.o R  xdccf_locnames
ioconf.o R  xyccf_locnames
iop.o T  iop_table_add_row
iop.o T  iop_table_clear
ip6_input.o C  ip6_forward_srcrt
ip6_input.o C  ip6_sourcecheck
ip6_input.o C  ip6_sourcecheck_interval
ip6_mroute.o D  ip6_mrtproto
ip_auth.o D  fr_authsize
ip_ecn.o T  ip6_ecn_ingress
ip_encap.o T  encap_attach
ip_fil.o T  fr_forgetifp
ip_fil.o T  iplinit
ip_icmp.o D  icmpmask
ip_icmp.o T  ip_next_mtu
ip_input.o C  in_ifaddrentries
ip_input.o T  ip_stripoptions
ip_proxy.o C  ap_sess_tab
ip_proxy.o T  appr_add
ip_proxy.o T  appr_del
ip_proxy.o T  ippr_h245_in
isa.o T  isa_intr_typename
isa_machdep.o T  isa_intr_evcnt
isa_machdep.o T  isa_mem_free
isa_machdep.o T  isa_reinit_irq
isadma.o T  _isa_dmafreeze
isadma.o T  _isa_dmathaw
isapnp.o T  isapnp_unconfig
isapnpdevs.o R  isapnp_cs_devinfo
isapnpdevs.o R  isapnp_fmv_devinfo
isapnpdevs.o R  isapnp_mpu_devinfo
iso.o T  iso_ck_addr
iso.o T  iso_hashchar
iso_pcb.o D  zeroiso_addr
iso_snpac.o T  snpac_ownmulti
iso_snpac.o T  snpac_rtrequest
kern_clock.o C  callwheelbits
kern_clock.o C  tickfix
kern_clock.o C  tickfixinterval
kern_descrip.o T  fdavail
kern_descrip.o T  fdclear
kern_lkm.o T  lkm_nofunc
kern_lkm.o T  lkmdispatch
kern_lock.o D  simple_lock_debugger
kern_lock.o T  spinlock_acquire_count
kern_lock.o T  spinlock_release_all
kern_malloc.o C  kmemstats
kern_malloc.o R  memname
kern_malloc.o T  dump_kmemstats
kern_ntptime.o T  sysctl_ntptime
kern_proc.o C  proclist_lock
kern_sig.o T  killproc
kern_subr.o T  dopowerhooks
kern_subr.o T  exithook_disestablish
kern_subr.o T  mountroothook_disestablish
kern_synch.o D  sched_lock
kern_synch.o T  awaken
kern_synch.o T  bpendtsleep
kern_sysctl.o T  sysctl_struct
layer_subr.o T  layer_checkvp
lfs_syscalls.o D  debug_cleaner
lfs_syscalls.o D  verbose_debug
lfs_vnops.o D  lfs_no_inactive
lfs_vnops.o T  lfs_itimes
linux_sigcode.o T  linux_rt_esigcode
linux_sigcode.o T  linux_rt_sigcode
llc_subr.o D  frame_names
llc_subr.o T  llc_trace
llc_subr.o T  sdl_checkaddrif
locore.o A  kernel_text
locore.o D  eintrcnt
locore.o T  Xintrspurious
locore.o T  eintrnames
locore.o T  fillw
locore.o T  intrnames
locore.o T  mpidle
locore.o T  start
machdep.o C  cpu_info_store
machdep.o C  cpu_serial
machdep.o C  dumpmem_high
machdep.o C  dumpmem_low
machdep.o D  dumpmag
machdep.o T  i386_init_pcb_tss_ldt
machdep.o T  idt_vec_alloc
machdep.o T  idt_vec_free
machdep.o T  idt_vec_set
mca_machdep.o T  mca_dma_set_ioport
mfs_vfsops.o T  mfs_initminiroot
midisyn.o T  midisyn_finetune
midway.o T  en_dump
midway.o T  en_dumpmem
mtrr_i686.o D  i686_mtrr_funcs
mtrr_i686.o T  i686_mtrr_init_first
mtrr_k6.o D  k6_mtrr_funcs
mtrr_k6.o T  k6_mtrr_init_first
mulaw.o T  alaw_to_slinear16_be
mulaw.o T  alaw_to_ulinear16_be
mulaw.o T  mulaw_to_slinear16_be
mulaw.o T  mulaw_to_ulinear16_be
mulaw.o T  slinear16_to_alaw_be
ncr53c9x.o D  ncr53c9x_debug
ncr53c9x.o T  ncr53c9x_readregs
ncr53c9x.o T  ncr53c9x_scsi_reset
nfs_vnops.o T  nfs_null
ntfs_subr.o T  ntfs_times
opl.o T  opl_detach
opl.o T  oplsyn_loadpatch
opl.o T  oplsyn_reset
oplinstrs.o R  opl3_instrs
param.o D  fscale
pas.o D  E_C_MPU401_IRQ_translate
pas.o D  I_C_2_PCM_DMA_translate
pas.o D  I_C_3_PCM_IRQ_translate
pci.o T  pci_get_powerstate
pci.o T  pci_set_powerstate
pci_machdep.o D  pci_conf_slock
pci_machdep.o T  pci_intr_evcnt
pcic_pci_machdep.o T  pcic_pci_machdep_chip_intr_disestablish
pcic_pci_machdep.o T  pcic_pci_machdep_chip_intr_establish
pcic_pci_machdep.o T  pcic_pci_machdep_pcic_intr_establish
pciide.o T  acard_pci_intr
pk_llcsubr.o T  npaidb_enrich
pk_output.o D  pk_output_cache
pk_timer.o D  pk_t22
pmap.o T  pmap_test_attrs
rndpool.o T  rndpool_get_pool
rndpool.o T  rndpool_get_poolsize
rndpool.o T  rndpool_increment_entropy_count
route.o C  wildcard
rrunner.o T  esh_fpstrategy
rtl81x9.o T  rtk_activate
rtl81x9.o T  rtk_detach
sb.o D  sb_device
scsi_base.o T  scsi_change_def
scsipi_base.o R  scsipi_nsyncparams
scsipi_base.o T  scsipi_grow_resources
scsipi_base.o T  scsipi_thread_call_callback
sd.o T  sd_reassign_blocks
siop.o D  E_abs_script_sched_slot0_Used
siop.o D  E_abs_tag0_Used
siop.o D  E_abs_targ0_Used
siop.o T  siop_dump_script
siop.o T  siop_printstats
siop_common.o T  siop_minphys
siop_common.o T  siop_ppr_neg
spec_vnops.o R  devcls
spec_vnops.o R  devin
spec_vnops.o R  devio
spec_vnops.o R  devioc
spec_vnops.o R  devopn
spec_vnops.o R  devout
spec_vnops.o R  devwait
spp_debug.o C  spp_debug
spp_debug.o C  spp_debx
spp_debug.o D  sppconsdebug
spp_debug.o R  sanames
spp_debug.o R  spptimers
spp_usrreq.o D  NspcbSize
spp_usrreq.o D  SppcbSize
subr_autoconf.o T  config_activate
subr_autoconf.o T  config_attach_pseudo
subr_autoconf.o T  config_cfattach_detach
subr_autoconf.o T  config_cfdriver_detach
subr_autoconf.o T  config_finalize_register
subr_autoconf.o T  evcnt_attach_dynamic
subr_autoconf.o T  evcnt_detach
subr_disk.o D  disklist_slock
subr_disk.o T  disk_find
subr_disk.o T  disk_resetstat
subr_pool.o D  pool_head_slock
subr_pool.o D  pool_logsize
subr_pool.o T  pool_chk
subr_pool.o T  pool_prime
subr_pool.o T  pool_print
subr_pool.o T  pool_sethiwat
subr_prf.o T  db_vprintf
subr_prf.o T  vlog
subr_prf.o T  vsprintf
subr_prop.o T  prop_copy
subr_prop.o T  prop_delete
subr_prop.o T  prop_get
subr_prop.o T  prop_list
subr_prop.o T  prop_objs
subr_prop.o T  prop_set
subr_prop.o T  propdb_create
subr_prop.o T  propdb_destroy
subr_userconf.o D  userconf_maxlocnames
subr_userconf.o T  userconf_add_read
subr_xxx.o T  enoioctl
subr_xxx.o T  enosys
subr_xxx.o T  enxio
svr4_net.o T  svr4_netattach
sysmon_wdog.o D  sysmon_wdog_list_slock
sysmon_wdog.o D  sysmon_wdog_slock
sysmon_wdog.o T  sysmon_wdog_unregister
tcic2.o T  tcic_create_event_thread
tcp_timer.o R  tcp_totbackoff
tp_astring.o D  tp_estring
tp_astring.o D  tp_sstring
tp_inet.o T  tpin_quench
tp_timer.o T  tp_ctimeout_MIN
tp_timer.o T  tp_cuntimeout
tp_timer.o T  tp_euntimeout
tp_usrreq.o C  TNew
tp_usrreq.o C  TPNagle1
tp_usrreq.o C  TPNagle2
tp_usrreq.o C  tp_intercepts
tp_usrreq.o T  tp_ltrace
tropic.o T  tr_activate
tropic.o T  tr_detach
tty_conf.o T  ttyldisc_remove
tty_subr.o T  cinit
tulip.o R  tlp_al981_phy_regmap_size
tulip.o R  tlp_winb_txthresh_tab
tulip.o T  tlp_activate
tulip.o T  tlp_detach
tulip.o T  tlp_dm9102_reset
ufs_quota.o T  dqref
uhidev.o D  repproto
uipc_domain.o T  pfctlinput2
uipc_mbuf.o T  m_copyup
ukbd.o T  ukbd_cnattach
usbdi.o T  usbd_get_buffer
usbdi.o T  usbd_get_endpoint_descriptor
usbdi.o T  usbd_get_interface
usbdi.o T  usbd_pipe2device_handle
usbdi_util.o T  usbd_clear_hub_feature
usbdi_util.o T  usbd_get_hub_status
usbdi_util.o T  usbd_get_protocol
usbdi_util.o T  usbd_set_hub_feature
usbdi_util.o T  usbd_set_protocol
uvm_amap.o T  amap_share_protect
uvm_bio.o T  ubc_flush
uvm_map.o T  uvmspace_unshare
uvm_pager.o C  uvm_aiobuf_pool
uvm_stat.o T  uvmcnt_dump
uvm_unix.o T  uvm_grow
vers.o R  sccs
vfs_bio.o T  breada
vfs_bio.o T  count_lock_queue
vfs_subr.o C  kinfo_vgetfailed
vfs_subr.o C  rootfs
vfs_subr.o D  spechash_slock
vfs_subr.o D  vnode_free_list_slock
vga_isa.o T  vga_isa_cnattach
vga_pci.o T  vga_pci_cnattach
vm_machdep.o T  kvtop
vnd.o T  vnddetach
vnd.o T  vndshutdown
vnode_if.o R  vfs_op_descs
vnode_if.o T  VOP_REALLOCBLKS
wdc.o D  wdc_nxfer
wdc.o T  wdcrestart
wds.o T  wdsminphys
wsdisplay.o D  wsdisplay_noemul_ca
wsdisplay.o T  wsdisplaydevprint
wsfont.o T  wsfont_enum
wsfont.o T  wsfont_map_unichar
zlib.o R  deflate_copyright
zlib.o R  inflate_copyright