NVDIMM Device and Persistent Memory development
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From: "Zhijian Li (Fujitsu)" <lizhijian@fujitsu.com>
To: Vishal Verma <vishal.l.verma@intel.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	David Hildenbrand <david@redhat.com>,
	Oscar Salvador <osalvador@suse.de>,
	Dan Williams <dan.j.williams@intel.com>,
	Dave Jiang <dave.jiang@intel.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"nvdimm@lists.linux.dev" <nvdimm@lists.linux.dev>,
	"linux-cxl@vger.kernel.org" <linux-cxl@vger.kernel.org>,
	Huang Ying <ying.huang@intel.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>,
	Michal Hocko <mhocko@suse.com>,
	Jonathan Cameron <Jonathan.Cameron@Huawei.com>,
	Jeff Moyer <jmoyer@redhat.com>
Subject: Re: [PATCH v10 3/3] dax/kmem: allow kmem to add memory with memmap_on_memory
Date: Fri, 8 Dec 2023 09:11:28 +0000	[thread overview]
Message-ID: <5cc325c9-c872-4cd5-be98-61b14ecac9ad@fujitsu.com> (raw)
In-Reply-To: <20231107-vv-kmem_memmap-v10-3-1253ec050ed0@intel.com>



On 07/11/2023 15:22, Vishal Verma wrote:
> 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.
> 
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: David Hildenbrand <david@redhat.com>
> 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: Huang Ying <ying.huang@intel.com>
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> Reviewed-by: David Hildenbrand <david@redhat.com>
> Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
> Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>


Tested-by: Li Zhijian <lizhijian@fujitsu.com>  # both cxl.kmem and nvdimm.kmem




> ---
>   drivers/dax/bus.h         | 1 +
>   drivers/dax/dax-private.h | 1 +
>   drivers/dax/bus.c         | 3 +++
>   drivers/dax/cxl.c         | 1 +
>   drivers/dax/hmem/hmem.c   | 1 +
>   drivers/dax/kmem.c        | 8 +++++++-
>   drivers/dax/pmem.c        | 1 +
>   7 files changed, 15 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/dax/bus.h b/drivers/dax/bus.h
> index 1ccd23360124..cbbf64443098 100644
> --- a/drivers/dax/bus.h
> +++ b/drivers/dax/bus.h
> @@ -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);
> diff --git a/drivers/dax/dax-private.h b/drivers/dax/dax-private.h
> index 27cf2daaaa79..446617b73aea 100644
> --- a/drivers/dax/dax-private.h
> +++ b/drivers/dax/dax-private.h
> @@ -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;
> diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c
> index 1659b787b65f..1ff1ab5fa105 100644
> --- a/drivers/dax/bus.c
> +++ b/drivers/dax/bus.c
> @@ -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;
> diff --git a/drivers/dax/cxl.c b/drivers/dax/cxl.c
> index 8bc9d04034d6..c696837ab23c 100644
> --- a/drivers/dax/cxl.c
> +++ b/drivers/dax/cxl.c
> @@ -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));
> diff --git a/drivers/dax/hmem/hmem.c b/drivers/dax/hmem/hmem.c
> index 5d2ddef0f8f5..b9da69f92697 100644
> --- a/drivers/dax/hmem/hmem.c
> +++ b/drivers/dax/hmem/hmem.c
> @@ -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));
> diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c
> index 369c698b7706..42ee360cf4e3 100644
> --- a/drivers/dax/kmem.c
> +++ b/drivers/dax/kmem.c
> @@ -12,6 +12,7 @@
>   #include <linux/mm.h>
>   #include <linux/mman.h>
>   #include <linux/memory-tiers.h>
> +#include <linux/memory_hotplug.h>
>   #include "dax-private.h"
>   #include "bus.h"
>   
> @@ -93,6 +94,7 @@ static int dev_dax_kmem_probe(struct dev_dax *dev_dax)
>   	struct dax_kmem_data *data;
>   	struct memory_dev_type *mtype;
>   	int i, rc, mapped = 0;
> +	mhp_t mhp_flags;
>   	int numa_node;
>   	int adist = MEMTIER_DEFAULT_DAX_ADISTANCE;
>   
> @@ -179,12 +181,16 @@ static int dev_dax_kmem_probe(struct dev_dax *dev_dax)
>   		 */
>   		res->flags = IORESOURCE_SYSTEM_RAM;
>   
> +		mhp_flags = MHP_NID_IS_MGID;
> +		if (dev_dax->memmap_on_memory)
> +			mhp_flags |= MHP_MEMMAP_ON_MEMORY;
> +
>   		/*
>   		 * Ensure that future kexec'd kernels will not treat
>   		 * this as RAM automatically.
>   		 */
>   		rc = add_memory_driver_managed(data->mgid, range.start,
> -				range_len(&range), kmem_name, MHP_NID_IS_MGID);
> +				range_len(&range), kmem_name, mhp_flags);
>   
>   		if (rc) {
>   			dev_warn(dev, "mapping%d: %#llx-%#llx memory add failed\n",
> diff --git a/drivers/dax/pmem.c b/drivers/dax/pmem.c
> index ae0cb113a5d3..f3c6c67b8412 100644
> --- a/drivers/dax/pmem.c
> +++ b/drivers/dax/pmem.c
> @@ -63,6 +63,7 @@ static struct dev_dax *__dax_pmem_probe(struct device *dev)
>   		.id = id,
>   		.pgmap = &pgmap,
>   		.size = range_len(&range),
> +		.memmap_on_memory = false,
>   	};
>   
>   	return devm_create_dev_dax(&data);
> 

      reply	other threads:[~2023-12-08  9:12 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-11-07  7:22 [PATCH v10 0/3] mm: use memmap_on_memory semantics for dax/kmem Vishal Verma
2023-11-07  7:22 ` [PATCH v10 1/3] mm/memory_hotplug: replace an open-coded kmemdup() in add_memory_resource() Vishal Verma
2023-11-07  7:22 ` [PATCH v10 2/3] mm/memory_hotplug: split memmap_on_memory requests across memblocks Vishal Verma
2023-11-07  7:22 ` [PATCH v10 3/3] dax/kmem: allow kmem to add memory with memmap_on_memory Vishal Verma
2023-12-08  9:11   ` Zhijian Li (Fujitsu) [this message]

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