Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1350723

Re: [PATCH v2] x86: PAT: Documentation: rewrite "MTRR effects on PAT / non-PAT systems"

Show all headers | View raw

On Fri, Mar 04, 2016 at 04:03:04PM -0800, Paul E. McKenney wrote:
> On Fri, Mar 04, 2016 at 02:45:01PM -0800, Luis R. Rodriguez wrote:
> > The current documentation refers to using set_memory_wc() as a
> > possible hole strategy when you have overlapping ioremap() regions,
> > that's incorrect as set_memory_*() helpers can only be used on RAM,
> > not IO memory. Using set_memory_wc() will not fail, that's a problem
> > which must be corrected in the future. This fixes that, and updates
> > the documention to *strongly* discourage overlapping ioremap() memory
> > uses, but also documents a possible solution should there really be
> > no other option to remain compatible on both PAT and MTRR memory
> > constarained systems. While at it, this provides some same guidlines
> > to system designers to remain sane and compatible on both PAT and
> > non-PAT systems.
> > 
> > As per Toshi this also fixes the table for the effective memory type
> > when using MTRR WC on PAT UC- to WC.
> > 
> > Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
> 
> And I was really confused during my earlier reply.  For some reason
> I read the filename as memory-barriers.txt.
> 
> This one is not mine.  Too much time in standards committee meetings,
> I guess.  ;-)

Heh, OK yeah I was confused why you wanted to pick it up but played along.
Boris, can this go through you as its a follow up that previously went
through you ?

  Luis

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

Re: [PATCH] x86: PAT: Documentation: update overlapping ioremap hack  recommendation "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-03-04 20:30 +0100
  Re: [PATCH] x86: PAT: Documentation: update overlapping ioremap hack  recommendation "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-03-04 22:10 +0100
    [PATCH v2] x86: PAT: Documentation: rewrite "MTRR effects on PAT / non-PAT systems" "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-03-04 23:50 +0100
      Re: [PATCH v2] x86: PAT: Documentation: rewrite "MTRR effects on PAT  / non-PAT systems" "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-03-05 01:10 +0100
        Re: [PATCH v2] x86: PAT: Documentation: rewrite "MTRR effects on PAT  / non-PAT systems" "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-03-05 02:10 +0100
      RE: [PATCH v2] x86: PAT: Documentation: rewrite "MTRR effects on  PAT / non-PAT systems" "Elliott, Robert (Persistent Memory)" <elliott@hpe.com> - 2016-03-05 05:50 +0100
        Re: [PATCH v2] x86: PAT: Documentation: rewrite "MTRR effects on PAT  / non-PAT systems" "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-03-15 23:30 +0100
      Re: [PATCH v2] x86: PAT: Documentation: rewrite "MTRR effects on PAT  / non-PAT systems" Ingo Molnar <mingo@kernel.org> - 2016-03-05 13:00 +0100
        Re: [PATCH v2] x86: PAT: Documentation: rewrite "MTRR effects on PAT  / non-PAT systems" "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-03-15 23:30 +0100

csiph-web