Re: [PATCH 4/5] x86, mm: Add set_memory_wt() for WT

From: Andy Lutomirski
Date: Thu Sep 04 2014 - 15:15:22 EST

On Thu, Sep 4, 2014 at 11:57 AM, Toshi Kani <toshi.kani@xxxxxx> wrote:
> On Thu, 2014-09-04 at 11:57 -0700, Andy Lutomirski wrote:
>> On Thu, Sep 4, 2014 at 11:35 AM, Toshi Kani <toshi.kani@xxxxxx> wrote:
>> > This patch adds set_memory_wt(), set_memory_array_wt(), and
>> > set_pages_array_wt() for setting range(s) of memory to WT.
>> >
>> Possibly dumb question: I thought that set_memory_xyz was only for
>> RAM. Is that incorrect?
> It works for non-RAM ranges as well. For instance, you can use
> set_memory_xyz() to change cache attribute for a non-RAM range mapped by
> ioremap_cache().

OK -- I didn't realize that was legal.

Do you, by any chance, have a test driver for this? For example,
something that lets your reserve some WT memory at boot and mmap it?
I wouldn't mind getting some benchmarks, and I can even throw it at
the NV-DIMM box that's sitting under my desk :)

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