memory type e820
kostikbel at gmail.com
Wed Nov 5 18:28:49 UTC 2014
On Wed, Nov 05, 2014 at 11:22:21PM +0530, Sourish Mazumder wrote:
> Should there be any difference in performance while writing to a memory as
> cached versus uncached mapping?
Obviously, there should.
On the other hand, I do not understand how this question is related to
the discussion below.
> On Tue, Nov 4, 2014 at 2:16 PM, Konstantin Belousov <kostikbel at gmail.com>
> > On Mon, Nov 03, 2014 at 01:52:44PM -0500, John Baldwin wrote:
> > > On Saturday 01 November 2014 18:55:53 Sourish Mazumder wrote:
> > > > Hi John,
> > > >
> > > > I tried the pmap_mapdev() as suggested by you. Works perfectly. Thanks
> > for
> > > > the information.
> > >
> > > Sure.
> > >
> > > > What is required, If I want to add this nvram memory to VM pages?
> > >
> > > Hmm. If this is device memory you generally don't want that. I'm not
> > > actually sure how to do this at runtime. If you don't mind having a
> > local
> > > hack you can add a change in the MD startup code (e.g. in hammer_time()
> > > in sys/amd64/amd64/machdep.c) to adjust the ranges added to
> > > phys_avail and dump_avail.
> > The facility exists to do this. It is OBJT_MGTDEVICE pager and
> > vm_phys_fictitious_reg_range(). This is used by i915 and TTM for
> > aperture, and seems XEN dom0 code uses it for mapping pages from
> > other domains into dom0.
> Sourish Mazumder
More information about the freebsd-amd64