Re: [PATCH v2 6/6] x86, pat: Update documentation for WT changes

From: Toshi Kani
Date: Wed Sep 10 2014 - 17:45:48 EST


On Wed, 2014-09-10 at 13:29 -0700, Andy Lutomirski wrote:
> On Wed, Sep 10, 2014 at 1:12 PM, Toshi Kani <toshi.kani@xxxxxx> wrote:
> > On Wed, 2014-09-10 at 11:30 -0700, Andy Lutomirski wrote:
> >> On Wed, Sep 10, 2014 at 9:51 AM, Toshi Kani <toshi.kani@xxxxxx> wrote:
> >> > +Drivers may map the entire NV-DIMM range with ioremap_cache and then change
> >> > +a specific range to wt with set_memory_wt.
> >>
> >> That's mighty specific :)
> >
> > How about below?
> >
> > Drivers may use set_memory_wt to set WT type for cached reserve ranges.
>
> Do they have to be cached?

Yes, set_memory_xyz only supports WB->type->WB transition.

> How about:
>
> Drivers may call set_memory_wt on ioremapped ranges. In this case,
> there is no need to change the memory type back before calling
> iounmap.
>
> (Or only on cached ioremapped ranges if that is, in fact, the case.)

Sounds good. Yes, I will use cashed ioremapped ranges.

Thanks,
-Toshi


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