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From: Dan Williams <dan.j.williams@intel.com>
To: akpm@linux-foundation.org
Cc: 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>,
	Will Deacon <will@kernel.org>,
	joao.m.martins@oracle.com, peterz@infradead.org,
	dave.hansen@linux.intel.com, linux-mm@kvack.org,
	linux-nvdimm@lists.01.org, linux-kernel@vger.kernel.org,
	linux-acpi@vger.kernel.org, dri-devel@lists.freedesktop.org
Subject: [PATCH v3 07/23] ACPI: HMAT: Attach a device for each soft-reserved range
Date: Fri, 31 Jul 2020 20:25:39 -0700
Message-ID: <159625233946.3040297.14289523802580847523.stgit@dwillia2-desk3.amr.corp.intel.com> (raw)
In-Reply-To: <159625229779.3040297.11363509688097221416.stgit@dwillia2-desk3.amr.corp.intel.com>

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".

The driver depends on the architecture providing phys_to_target_node()
which is only x86 via numa_meminfo() and arm64 via a generic memblock
implementation.

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>
Reviewed-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/dax/hmem/Makefile |    3 ++-
 drivers/dax/hmem/device.c |   35 +++++++++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/drivers/dax/hmem/Makefile b/drivers/dax/hmem/Makefile
index a9d353d0c9ed..57377b4c3d47 100644
--- a/drivers/dax/hmem/Makefile
+++ b/drivers/dax/hmem/Makefile
@@ -1,5 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 obj-$(CONFIG_DEV_DAX_HMEM) += dax_hmem.o
-obj-$(CONFIG_DEV_DAX_HMEM_DEVICES) += device.o
+obj-$(CONFIG_DEV_DAX_HMEM_DEVICES) += device_hmem.o
 
+device_hmem-y := device.o
 dax_hmem-y := hmem.o
diff --git a/drivers/dax/hmem/device.c b/drivers/dax/hmem/device.c
index b9dd6b27745c..cb6401c9e9a4 100644
--- a/drivers/dax/hmem/device.c
+++ b/drivers/dax/hmem/device.c
@@ -5,6 +5,9 @@
 #include <linux/dax.h>
 #include <linux/mm.h>
 
+static bool nohmem;
+module_param_named(disable, nohmem, bool, 0444);
+
 void hmem_register_device(int target_nid, struct resource *r)
 {
 	/* define a clean / non-busy resource for the platform device */
@@ -17,6 +20,9 @@ void hmem_register_device(int target_nid, struct resource *r)
 	struct memregion_info info;
 	int rc, id;
 
+	if (nohmem)
+		return;
+
 	rc = region_intersects(res.start, resource_size(&res), IORESOURCE_MEM,
 			IORES_DESC_SOFT_RESERVED);
 	if (rc != REGION_INTERSECTS)
@@ -63,3 +69,32 @@ void hmem_register_device(int target_nid, struct resource *r)
 out_pdev:
 	memregion_free(id);
 }
+
+static __init int hmem_register_one(struct resource *res, void *data)
+{
+	/*
+	 * If the resource is not a top-level resource it was already
+	 * assigned to a device by the HMAT parsing.
+	 */
+	if (res->parent != &iomem_resource) {
+		pr_info("HMEM: skip %pr, already claimed\n", res);
+		return 0;
+	}
+
+	hmem_register_device(phys_to_target_node(res->start), res);
+
+	return 0;
+}
+
+static __init int hmem_init(void)
+{
+	walk_iomem_res_desc(IORES_DESC_SOFT_RESERVED,
+			IORESOURCE_MEM, 0, -1, NULL, hmem_register_one);
+	return 0;
+}
+
+/*
+ * As this is a fallback for address ranges unclaimed by the ACPI HMAT
+ * parsing it must be at an initcall level greater than hmat_init().
+ */
+late_initcall(hmem_init);
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  parent reply index

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-01  3:24 [PATCH v3 00/23] device-dax: Support sub-dividing soft-reserved ranges Dan Williams
2020-08-01  3:25 ` [PATCH v3 01/23] x86/numa: Cleanup configuration dependent command-line options Dan Williams
2020-08-01  3:25 ` [PATCH v3 02/23] x86/numa: Add 'nohmat' option Dan Williams
2020-08-01  3:51   ` Randy Dunlap
2020-08-01 16:36     ` Dan Williams
2020-08-01  3:25 ` [PATCH v3 03/23] efi/fake_mem: Arrange for a resource entry per efi_fake_mem instance Dan Williams
2020-08-01  3:25 ` [PATCH v3 04/23] ACPI: HMAT: Refactor hmat_register_target_device to hmem_register_device Dan Williams
2020-08-01  3:25 ` [PATCH v3 05/23] resource: Report parent to walk_iomem_res_desc() callback Dan Williams
2020-08-01  3:25 ` [PATCH v3 06/23] mm/memory_hotplug: Introduce default phys_to_target_node() implementation Dan Williams
2020-08-01  6:24   ` kernel test robot
2020-08-01 16:39   ` kernel test robot
2020-08-01  3:25 ` Dan Williams [this message]
2020-08-01  3:25 ` [PATCH v3 08/23] device-dax: Drop the dax_region.pfn_flags attribute Dan Williams
2020-08-01  3:25 ` [PATCH v3 09/23] device-dax: Move instance creation parameters to 'struct dev_dax_data' Dan Williams
2020-08-01  3:25 ` [PATCH v3 10/23] device-dax: Make pgmap optional for instance creation Dan Williams
2020-08-01  3:26 ` [PATCH v3 11/23] device-dax: Kill dax_kmem_res Dan Williams
2020-08-01  3:26 ` [PATCH v3 12/23] device-dax: Add an allocation interface for device-dax instances Dan Williams
2020-08-01  3:26 ` [PATCH v3 13/23] device-dax: Introduce 'seed' devices Dan Williams
2020-08-01  3:26 ` [PATCH v3 14/23] drivers/base: Make device_find_child_by_name() compatible with sysfs inputs Dan Williams
2020-08-01  3:26 ` [PATCH v3 15/23] device-dax: Add resize support Dan Williams
2020-08-01  3:26 ` [PATCH v3 16/23] mm/memremap_pages: Convert to 'struct range' Dan Williams
2020-08-01  3:26 ` [PATCH v3 17/23] mm/memremap_pages: Support multiple ranges per invocation Dan Williams
2020-08-01  3:26 ` [PATCH v3 18/23] device-dax: Add dis-contiguous resource support Dan Williams
2020-08-01  3:26 ` [PATCH v3 19/23] device-dax: Introduce 'mapping' devices Dan Williams
2020-08-01  3:26 ` [PATCH v3 20/23] device-dax: Make align a per-device property Dan Williams
2020-08-01  7:23   ` kernel test robot
2020-08-01  3:26 ` [PATCH v3 21/23] device-dax: Add an 'align' attribute Dan Williams
2020-08-01  6:14   ` kernel test robot
2020-08-01  6:18   ` kernel test robot
2020-08-01  3:27 ` [PATCH v3 22/23] dax/hmem: Introduce dax_hmem.region_idle parameter Dan Williams
2020-08-01  3:27 ` [PATCH v3 23/23] device-dax: Add a range mapping allocation attribute Dan Williams
2020-08-04 17:02 ` [PATCH v3 00/23] device-dax: Support sub-dividing soft-reserved ranges Jason Gunthorpe

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