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From: Will Deacon <will@kernel.org>
To: Dan Williams <dan.j.williams@intel.com>
Cc: linux-acpi@vger.kernel.org,
	Jonathan Cameron <Jonathan.Cameron@huawei.com>,
	Brice Goglin <Brice.Goglin@inria.fr>,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Catalin Marinas <catalin.marinas@arm.com>,
	peterz@infradead.org, dave.hansen@linux.intel.com,
	linux-nvdimm@lists.01.org, linux-kernel@vger.kernel.org,
	x86@kernel.org, joao.m.martins@oracle.com
Subject: Re: [PATCH v2 6/6] ACPI: HMAT: Attach a device for each soft-reserved range
Date: Wed, 25 Mar 2020 11:10:40 +0000	[thread overview]
Message-ID: <20200325111039.GA32109@willie-the-truck> (raw)
In-Reply-To: <158489357825.1457606.17352509511987748598.stgit@dwillia2-desk3.amr.corp.intel.com>

On Sun, Mar 22, 2020 at 09:12:58AM -0700, Dan Williams wrote:
> The hmem enabling in commit 'cf8741ac57ed ("ACPI: NUMA: HMAT: Register
> "soft reserved" memory as an "hmem" device")' only registered ranges to
> the hmem driver for each soft-reservation that also appeared in the
> HMAT. While this is meant to encourage platform firmware to "do the
> right thing" and publish an HMAT, the corollary is that platforms that
> fail to publish an accurate HMAT will strand memory from Linux usage.
> Additionally, the "efi_fake_mem" kernel command line option enabling
> will strand memory by default without an HMAT.
> 
> Arrange for "soft reserved" memory that goes unclaimed by HMAT entries
> to be published as raw resource ranges for the hmem driver to consume.
> 
> Include a module parameter to disable either this fallback behavior, or
> the hmat enabling from creating hmem devices. The module parameter
> requires the hmem device enabling to have unique name in the module
> namespace: "device_hmem".
> 
> Rather than mark this x86-only, include an interim phys_to_target_node()
> implementation for arm64.
> 
> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> Cc: Brice Goglin <Brice.Goglin@inria.fr>
> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
> Cc: Jeff Moyer <jmoyer@redhat.com>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Will Deacon <will@kernel.org>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
> ---
>  arch/arm64/mm/numa.c      |   13 +++++++++++++
>  drivers/dax/Kconfig       |    1 +
>  drivers/dax/hmem/Makefile |    3 ++-
>  drivers/dax/hmem/device.c |   33 +++++++++++++++++++++++++++++++++
>  4 files changed, 49 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/mm/numa.c b/arch/arm64/mm/numa.c
> index 4decf1659700..00fba21eaec0 100644
> --- a/arch/arm64/mm/numa.c
> +++ b/arch/arm64/mm/numa.c
> @@ -468,3 +468,16 @@ int memory_add_physaddr_to_nid(u64 addr)
>  	pr_warn("Unknown node for memory at 0x%llx, assuming node 0\n", addr);
>  	return 0;
>  }
> +
> +/*
> + * device-dax instance registrations want a valid target-node in case
> + * they are ever onlined as memory (see hmem_register_device()).
> + *
> + * TODO: consult cached numa info
> + */
> +int phys_to_target_node(phys_addr_t addr)
> +{
> +	pr_warn_once("Unknown target node for memory at 0x%llx, assuming node 0\n",
> +			addr);
> +	return 0;
> +}

Could you implement a generic version of this by iterating over the nodes
with for_each_{,online_}node() and checking for intersection with
node_{start,end}_pfn()?

Will
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  parent reply	other threads:[~2020-03-25 11:10 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-22 16:12 [PATCH v2 0/6] Manual definition of Soft Reserved memory devices Dan Williams
2020-03-22 16:12 ` [PATCH v2 1/6] x86/numa: Cleanup configuration dependent command-line options Dan Williams
2020-03-22 16:12 ` [PATCH v2 2/6] x86/numa: Add 'nohmat' option Dan Williams
2020-03-22 16:12 ` [PATCH v2 3/6] efi/fake_mem: Arrange for a resource entry per efi_fake_mem instance Dan Williams
2020-03-22 16:12 ` [PATCH v2 4/6] ACPI: HMAT: Refactor hmat_register_target_device to hmem_register_device Dan Williams
2020-03-24 19:40   ` Joao Martins
2020-03-24 21:04     ` Dan Williams
2020-03-25 22:32       ` Dan Williams
2020-03-22 16:12 ` [PATCH v2 5/6] resource: Report parent to walk_iomem_res_desc() callback Dan Williams
2020-03-22 16:12 ` [PATCH v2 6/6] ACPI: HMAT: Attach a device for each soft-reserved range Dan Williams
2020-03-24 19:41   ` Joao Martins
2020-03-24 21:06     ` Dan Williams
2020-03-24 21:30       ` Joao Martins
2020-03-25 11:10   ` Will Deacon [this message]
2020-03-25 17:10     ` Dan Williams
2020-03-25 10:02 ` [PATCH v2 0/6] Manual definition of Soft Reserved memory devices Rafael J. Wysocki

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