Commit 4eca0ef4 authored by Vishal Verma's avatar Vishal Verma Committed by Andrew Morton
Browse files

dax/kmem: allow kmem to add memory with memmap_on_memory 

Large amounts of memory managed by the kmem driver may come in via CXL,
and it is often desirable to have the memmap for this memory on the new
memory itself.

Enroll kmem-managed memory for memmap_on_memory semantics if the dax
region originates via CXL.  For non-CXL dax regions, retain the existing
default behavior of hot adding without memmap_on_memory semantics.

Link: https://lkml.kernel.org/r/20231107-vv-kmem_memmap-v10-3-1253ec050ed0@intel.com


Signed-off-by: default avatarVishal Verma <vishal.l.verma@intel.com>
Reviewed-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
Reviewed-by: default avatar"Huang, Ying" <ying.huang@intel.com>
Tested-by: Li Zhijian <lizhijian@fujitsu.com>	[cxl.kmem and nvdimm.kmem]
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Fan Ni <fan.ni@samsung.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 6b8f0798

drivers/dax/bus.c

+3 −0
Original line number Diff line number Diff line
@@ -367,6 +367,7 @@ static ssize_t create_store(struct device *dev, struct device_attribute *attr, 
			.dax_region = dax_region,

			.size = 0,

			.id = -1,

			.memmap_on_memory = false,

		};

		struct dev_dax *dev_dax = devm_create_dev_dax(&data);
@@ -1400,6 +1401,8 @@ struct dev_dax *devm_create_dev_dax(struct dev_dax_data *data) 
	dev_dax->align = dax_region->align;

	ida_init(&dev_dax->ida);



	dev_dax->memmap_on_memory = data->memmap_on_memory;



	inode = dax_inode(dax_dev);

	dev->devt = inode->i_rdev;

	dev->bus = &dax_bus_type;

drivers/dax/bus.h

+1 −0
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ struct dev_dax_data { 
	struct dev_pagemap *pgmap;

	resource_size_t size;

	int id;

	bool memmap_on_memory;

};



struct dev_dax *devm_create_dev_dax(struct dev_dax_data *data);

drivers/dax/cxl.c

+1 −0
Original line number Diff line number Diff line
@@ -26,6 +26,7 @@ static int cxl_dax_region_probe(struct device *dev) 
		.dax_region = dax_region,

		.id = -1,

		.size = range_len(&cxlr_dax->hpa_range),

		.memmap_on_memory = true,

	};



	return PTR_ERR_OR_ZERO(devm_create_dev_dax(&data));

drivers/dax/dax-private.h

+1 −0
Original line number Diff line number Diff line
@@ -70,6 +70,7 @@ struct dev_dax { 
	struct ida ida;

	struct device dev;

	struct dev_pagemap *pgmap;

	bool memmap_on_memory;

	int nr_range;

	struct dev_dax_range {

		unsigned long pgoff;

drivers/dax/hmem/hmem.c

+1 −0
Original line number Diff line number Diff line
@@ -36,6 +36,7 @@ static int dax_hmem_probe(struct platform_device *pdev) 
		.dax_region = dax_region,

		.id = -1,

		.size = region_idle ? 0 : range_len(&mri->range),

		.memmap_on_memory = false,

	};



	return PTR_ERR_OR_ZERO(devm_create_dev_dax(&data));