cvs commit: src/sys/amd64/amd64 pmap.c src/sys/i386/i386 pmap.c

[John Baldwin]

On Tuesday 24 April 2007 05:18:59 am Yar Tikhiy wrote:
> On Sat, Apr 21, 2007 at 09:54:12AM -0600, Coleman Kane wrote:
> > On Sat, 2007-04-21 at 17:03 +0200, Andre Oppermann wrote:
> > > Stephan Uphoff wrote:
> > > > ups         2007-04-21 14:17:30 UTC
> > > > 
> > > >   FreeBSD src repository
> > > > 
> > > >   Modified files:
> > > >     sys/amd64/amd64      pmap.c 
> > > >     sys/i386/i386        pmap.c 
> > > >   Log:
> > > >   Modify TLB invalidation handling.
> > > >   
> > > >   Reviewed by:    alc@, peter@
> > > >   MFC after:      1 week
> > > 
> > > Could you be a bit more verbose what changed here and why it
> > > was done?
> > > 
> > 
> > I agree. I would really like to know what the modification accomplishes.
> 
> Alas, we don't live in an ideal world.  If we did, our commit
> messages would always follow the well-known guideline:
> 
> 0. Tell the essence of the change.
> 1. Give the reason for the change.
> 2. Explain the change unless it's trivial.

The point of the modification is to make sure we don't clear TLB entries for 
pages whose mappings are being removed until we've also made any necessary 
updates to other entries higher in the page table hierarchy such as pde's 
etc.  We've seen some really bizarre "bad pte" panics at work that this 
change fixes.

-- 
John Baldwin