From: Dan Williams <dan.j.williams@intel.com>
To: Jeff Moyer <jmoyer@redhat.com>
Cc: Linux ACPI <linux-acpi@vger.kernel.org>,
Jason Gunthorpe <jgg@ziepe.ca>,
Peter Zijlstra <peterz@infradead.org>,
Ard Biesheuvel <ardb@kernel.org>,
Jonathan Cameron <Jonathan.Cameron@huawei.com>,
Borislav Petkov <bp@alien8.de>,
Wei Yang <richardw.yang@linux.intel.com>, X86 ML <x86@kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>,
Brice Goglin <Brice.Goglin@inria.fr>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Andy Lutomirski <luto@kernel.org>,
Tom Lendacky <thomas.lendacky@amd.com>,
linux-nvdimm <linux-nvdimm@lists.01.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Joao Martins <joao.m.martins@oracle.com>
Subject: Re: [PATCH 0/5] Manual definition of Soft Reserved memory devices
Date: Fri, 6 Mar 2020 13:05:30 -0800 [thread overview]
Message-ID: <CAPcyv4jCWtPf0XEHfw6GGGE80k0_wKpoaruopRFJwKcsHk18gw@mail.gmail.com> (raw)
In-Reply-To: <x49a74tnt6n.fsf@segfault.boston.devel.redhat.com>
On Fri, Mar 6, 2020 at 12:07 PM Jeff Moyer <jmoyer@redhat.com> wrote:
>
> Dan Williams <dan.j.williams@intel.com> writes:
>
> > Given the current dearth of systems that supply an ACPI HMAT table, and
> > the utility of being able to manually define device-dax "hmem" instances
> > via the efi_fake_mem= option, relax the requirements for creating these
> > devices. Specifically, add an option (numa=nohmat) to optionally disable
> > consideration of the HMAT and update efi_fake_mem= to behave like
> > memmap=nn!ss in terms of delimiting device boundaries.
>
> So, am I correct in deducing that your primary motivation is testing
> without hardware/firmware support?
My primary motivation is making the dax_kmem facility useful to
shipping platforms that have performance differentiated memory, but
may not have EFI-defined soft-reservations / HMAT (or
non-EFI-ACPI-platform equivalent). I'm anticipating HMAT enabled
platforms where the platform firmware policy for what is
soft-reserved, or not, is not the policy the system owner would pick.
I'd also highlight Joao's work [1] (see the TODO section) as an
indication of the demand for custom carving memory resources and
applying the device-dax memory management interface.
> This looks like a bit of a hack to
> me, and I think maybe it would be better to just emulate the HMAT using
> qemu. I don't have a strong objection, though.
Yeah, qemu emulation does not help when you, the system owner, have a
different use case than what the bare-metal platform-firmware
envisioned for "specific-purpose memory".
[1]: https://lore.kernel.org/lkml/20200110190313.17144-1-joao.m.martins@oracle.com/
prev parent reply other threads:[~2020-03-06 21:05 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-02 22:19 [PATCH 0/5] Manual definition of Soft Reserved memory devices Dan Williams
2020-03-02 22:20 ` [PATCH 1/5] ACPI: NUMA: Add 'nohmat' option Dan Williams
2020-03-18 0:08 ` Dan Williams
2020-03-18 8:24 ` Rafael J. Wysocki
2020-03-18 17:39 ` Dan Williams
2020-03-19 9:30 ` Rafael J. Wysocki
2020-03-02 22:20 ` [PATCH 2/5] efi/fake_mem: Arrange for a resource entry per efi_fake_mem instance Dan Williams
2020-03-03 8:01 ` Ard Biesheuvel
2020-03-02 22:20 ` [PATCH 3/5] ACPI: HMAT: Refactor hmat_register_target_device to hmem_register_device Dan Williams
2020-03-02 22:20 ` [PATCH 4/5] resource: Report parent to walk_iomem_res_desc() callback Dan Williams
2020-03-05 14:42 ` Tom Lendacky
2020-03-17 22:04 ` Dan Williams
2020-03-02 22:20 ` [PATCH 5/5] ACPI: HMAT: Attach a device for each soft-reserved range Dan Williams
2020-03-06 20:07 ` [PATCH 0/5] Manual definition of Soft Reserved memory devices Jeff Moyer
2020-03-06 21:05 ` Dan Williams [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CAPcyv4jCWtPf0XEHfw6GGGE80k0_wKpoaruopRFJwKcsHk18gw@mail.gmail.com \
--to=dan.j.williams@intel.com \
--cc=Brice.Goglin@inria.fr \
--cc=Jonathan.Cameron@huawei.com \
--cc=ard.biesheuvel@linaro.org \
--cc=ardb@kernel.org \
--cc=bp@alien8.de \
--cc=dave.hansen@linux.intel.com \
--cc=hpa@zytor.com \
--cc=jgg@ziepe.ca \
--cc=jmoyer@redhat.com \
--cc=joao.m.martins@oracle.com \
--cc=linux-acpi@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-nvdimm@lists.01.org \
--cc=luto@kernel.org \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=richardw.yang@linux.intel.com \
--cc=rjw@rjwysocki.net \
--cc=tglx@linutronix.de \
--cc=thomas.lendacky@amd.com \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).