cvs commit: src/sys/vm vm_map.c

[Julian Elischer]

Peter Wemm wrote:

>peter       2004-07-21 00:29:21 UTC
>
>  FreeBSD src repository
>
>  Modified files:
>    sys/vm               vm_map.c 
>  Log:
>  Move the initialization and teardown of pmaps to the vmspace zone's
>  init and fini handlers.  Our vm system removes all userland mappings at
>  exit prior to calling pmap_release.  It just so happens that we might
>  as well reuse the pmap for the next process since the userland slate
>  has already been wiped clean.
>  
>  However.  There is a functional benefit to this as well.  For platforms
>  that share userland and kernel context in the same pmap, it means that
>  the kernel portion of a pmap remains valid after the vmspace has been
>  freed (process exit) and while it is in uma's cache.  This is significant
>  for i386 SMP systems with kernel context borrowing because it avoids
>  a LOT of IPIs from the pmap_lazyfix() cleanup in the usual case.
>

Just thought of something..
if the kernel section of a pmap gets changed,
does the system scan all processes to fix them? and if it does, does it
do those in the cache?

I have to go look at the pmap code again....

>  
>  Tested on:  amd64, i386, sparc64, alpha
>  Glanced at by:  alc
>  
>  Revision  Changes    Path
>  1.343     +2 -3      src/sys/vm/vm_map.c
>  
>