cvs commit: src/sys/vm vm_map.c vm_map.h

[John Baldwin]

On Friday 30 July 2004 12:06 pm, Brian Fundakowski Feldman wrote:
> On Fri, Jul 30, 2004 at 09:10:28AM +0000, Maxime Henrion wrote:
> > mux         2004-07-30 09:10:28 UTC
> >
> >   FreeBSD src repository
> >
> >   Modified files:
> >     sys/vm               vm_map.c vm_map.h
> >   Log:
> >   Get rid of another lockmgr(9) consumer by using sx locks for the user
> >   maps.  We always acquire the sx lock exclusively here, but we can't
> >   use a mutex because we want to be able to sleep while holding the
> >   lock.  This is completely equivalent to what we were doing with the
> >   lockmgr(9) locks before.
>
> Not that I don't think it's worth doing in general, but is there a
> comparison anyone has done between speeds of sx and lockmgr?

Speed aside, when allproc_lock and proctree_lock were lockmgr locks (before sx 
was implemented), my SMP machines routinely locked up and when I looked at 
things in the debugger it seemed that no one held allproc_lock but several 
processes were blocked on it.  Quite frankly, I don't trust lockmgr()'s 
implementation.

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