linux-kernel - Re: [PATCH 4/5] x86, mm: Add set_memory

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Date:	Thu, 04 Sep 2014 13:30:49 -0600
From:	Toshi Kani <toshi.kani@...com>
To:	Andy Lutomirski <luto@...capital.net>
Cc:	"H. Peter Anvin" <hpa@...or.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>, akpm@...uxfoundation.org,
	Arnd Bergmann <arnd@...db.de>,
	"linux-mm@...ck.org" <linux-mm@...ck.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Juergen Gross <jgross@...e.com>,
	Stefan Bader <stefan.bader@...onical.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
Subject: Re: [PATCH 4/5] x86, mm: Add set_memory_wt() for WT

On Thu, 2014-09-04 at 12:14 -0700, Andy Lutomirski wrote:
> On Thu, Sep 4, 2014 at 11:57 AM, Toshi Kani <toshi.kani@...com> 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@...com> 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 :)

Yes, the attached file contains two test tools.  Please update
NVDIMM_ADDR to your NV-DIMM address in test-wt.c and test.c.

1) mmap via /dev/mem
dev-mem-test/mem-wt.patch - kernel patch that tweaks /dev/mem
dev-mem-test/test-wt.c - user program that mmaps a NVDIMM range w/ WT

2) Test driver for testing the interfaces
interfaces-test/Makefile
interfaces-test/test.c

Thanks,
-Toshi

Download attachment "tests.tgz" of type "application/x-compressed-tar" (2454 bytes)