cvs commit: src/sys/kern kern_malloc.c src/sys/sys malloc.h src/sys/vm memguard.c memguard.h

[John Baldwin]

On Friday 30 December 2005 08:42 am, Pawel Jakub Dawidek wrote:
> On Fri, Dec 30, 2005 at 08:15:56AM -0500, John Baldwin wrote:
> +> On Friday 30 December 2005 06:45 am, Pawel Jakub Dawidek wrote:
> +> > pjd         2005-12-30 11:45:07 UTC
> +> >
> +> >   FreeBSD src repository
> +> >
> +> >   Modified files:
> +> >     sys/kern             kern_malloc.c
> +> >     sys/sys              malloc.h
> +> >     sys/vm               memguard.c memguard.h
> +> >   Log:
> +> >   Improve memguard a bit:
> +> >   - Provide tunable vm.memguard.desc, so one can specify memory type
> +> > without changing the code and recompiling the kernel.
> +> >   - Allow to use memguard for kernel modules by providing sysctl
> +> >     vm.memguard.desc, which can be changed to short description of
> memory +> >     type before module is loaded.
> +>
> +> You don't actually need a sysctl for this case.  You can use kenv to set
> a +> tunable after boot but before loading the module to achieve the same
> purpose. +> E.g.  'kenv vm.memguard.desc=FOO' will work and TUNABLE_FETCH
> will find it +> during a subsequent kldload.  Just FYI.
>
> But I need to control vm.memguard.desc change to be able to detect if
> memory type has allocated memory already, etc. and eventually deny the
> change.
> AFAIK it won't be possible with kenv.

For the case I quoted (_before_ kldload) you must be doing all that checking 
when you load the module either via MOD_LOAD in a module event or a SYSINIT.  
In that case, setting the tunable via kenv before you kldload is identical to 
setting the tunable in the loader, then booting and then kldloading the 
module.

-- 
John Baldwin <jhb at FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve"  =  http://www.FreeBSD.org