KernelOptions [FreeBSD WIKI]

This page is read only. You can view the source, but not change it. Ask your administrator if you think this is wrong.
====== NOTE: this information has become obsolete as of FreeBSD 8.0. ======

====== VImage kernel options ======
.. and what they mean from the user or implementation perspective.

===== VIMAGE =====

This will be the only option once the entire work is in.

If ''%%option VIMAGE%%'' is turned on this will allow creation of multiple virtual instances.
There will be indirection for each virtual instance like ''%%curvimage->vnet->mod_data[TYPE]%%''
though things might not be used that way but cached like ''%%thread->td_vnet%%''.
''%%mod_data[TYPE]%%'' will hold the container structures ''%%struct vnet_inet%%'', ''%%vnet_ipsec%%'', ...
for each ''%%TPYE%%'' like ''%%VNET_INET%%'', ''%%VNET_IPSEC%%'', ...

If ''%%nooption VIMAGE%%'' is set or there is no ''%%option VIMAGE%%'' there will be only one
instance and no virtualization will be possible. There will be one global for each
container struct. So a type of ''%%VNET_INET%%'' with the container struct ''%%struct vnet_inet%%''
will resolve to the global variable ''%%struct vnet_inet vnet_inet_0%%''.

===== VIMAGE_GLOBALS =====

During the transition period while bringing the work and moving from globals to the container structs
to the final product the intermediate ''%%option VIMAGE_GLOBALS%%'' will be used to distinguish between
using the former globals or the container structs.

This option will be removed (along with the globals) as soon as everything was merged.
It is basically there to allow benchmarking the same code with either the old globals or the new VImage logic.

===== option hierachie =====

If ''%%option VIMAGE%%'' is defined the final product will be used.
If ''%%option VIMAGE%%'' is not defined the the single global container structs will be used
unless ''%%option VIMAGE_GLOBALS%%'' is given. In that case we will fall back to the old globals.

| VIMAGE | VIMAGE_GLOBALS | Result |
| yes | yes | Not permitted. |
| yes | no | Support multiple virtual instances. |
| no | yes | Use the old globals. |
| no | no | Use single global container struct instances. |