Subject: Re: CVS commit: syssrc/sys/uvm
To: Chuck Silvers <chs@netbsd.org>
From: Jason R Thorpe <thorpej@wasabisystems.com>
List: tech-kern
Date: 12/31/2001 14:54:26
On Tue, Jan 01, 2002 at 12:34:41AM +0200, Chuck Silvers wrote:
> this change has the effect of causing MAP_PRIVATE mappings to be
> copied to anonymous memory when they are mlock()d, so that uvm_fault()
> doesn't need to copy these pages later when called from ptrace(), thus
> avoiding the call to pmap_page_protect() and the panic that results
> from this when the mlock()d region is unlocked or freed. note that
> this change doesn't help the case where the wired mapping is MAP_SHARED.
This is Bad. Running ntpd is now going to cause the entire libc to
be wired down into anonymous memory without any hope of sharing it
with other libc-using processes. This is a real screw for low-memory
systems.
--
-- Jason R. Thorpe <thorpej@wasabisystems.com>