8fc5c73554
Persistent memory, as described by the ACPI NFIT (NVDIMM Firmware Interface Table), is the first known instance of a memory range described by a unique "target" proximity domain. Where "initiator" and "target" proximity domains is an approach that the ACPI HMAT (Heterogeneous Memory Attributes Table) uses to described the unique performance properties of a memory range relative to a given initiator (e.g. CPU or DMA device). Currently the numa-node for a /dev/pmemX block-device or /dev/daxX.Y char-device follows the traditional notion of 'numa-node' where the attribute conveys the closest online numa-node. That numa-node attribute is useful for cpu-binding and memory-binding processes *near* the device. However, when the memory range backing a 'pmem', or 'dax' device is onlined (memory hot-add) the memory-only-numa-node representing that address needs to be differentiated from the set of online nodes. In other words, the numa-node association of the device depends on whether you can bind processes *near* the cpu-numa-node in the offline device-case, or bind process *on* the memory-range directly after the backing address range is onlined. Allow for the case that platform firmware describes persistent memory with a unique proximity domain, i.e. when it is distinct from the proximity of DRAM and CPUs that are on the same socket. Plumb the Linux numa-node translation of that proximity through the libnvdimm region device to namespaces that are in device-dax mode. With this in place the proposed kmem driver [1] can optionally discover a unique numa-node number for the address range as it transitions the memory from an offline state managed by a device-driver to an online memory range managed by the core-mm. [1]: https://lore.kernel.org/lkml/20181022201317.8558C1D8@viggo.jf.intel.com Reported-by: Fan Du <fan.du@intel.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: "Oliver O'Halloran" <oohall@gmail.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Jérôme Glisse <jglisse@redhat.com> Reviewed-by: Yang Shi <yang.shi@linux.alibaba.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
62 lines
1.8 KiB
C
62 lines
1.8 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright(c) 2016 - 2018 Intel Corporation. All rights reserved. */
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#ifndef __DAX_BUS_H__
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#define __DAX_BUS_H__
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#include <linux/device.h>
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struct dev_dax;
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struct resource;
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struct dax_device;
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struct dax_region;
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void dax_region_put(struct dax_region *dax_region);
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struct dax_region *alloc_dax_region(struct device *parent, int region_id,
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struct resource *res, int target_node, unsigned int align,
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unsigned long flags);
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enum dev_dax_subsys {
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DEV_DAX_BUS,
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DEV_DAX_CLASS,
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};
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struct dev_dax *__devm_create_dev_dax(struct dax_region *dax_region, int id,
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struct dev_pagemap *pgmap, enum dev_dax_subsys subsys);
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static inline struct dev_dax *devm_create_dev_dax(struct dax_region *dax_region,
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int id, struct dev_pagemap *pgmap)
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{
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return __devm_create_dev_dax(dax_region, id, pgmap, DEV_DAX_BUS);
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}
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/* to be deleted when DEV_DAX_CLASS is removed */
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struct dev_dax *__dax_pmem_probe(struct device *dev, enum dev_dax_subsys subsys);
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struct dax_device_driver {
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struct device_driver drv;
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struct list_head ids;
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int match_always;
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};
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int __dax_driver_register(struct dax_device_driver *dax_drv,
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struct module *module, const char *mod_name);
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#define dax_driver_register(driver) \
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__dax_driver_register(driver, THIS_MODULE, KBUILD_MODNAME)
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void dax_driver_unregister(struct dax_device_driver *dax_drv);
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void kill_dev_dax(struct dev_dax *dev_dax);
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#if IS_ENABLED(CONFIG_DEV_DAX_PMEM_COMPAT)
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int dev_dax_probe(struct device *dev);
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#endif
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/*
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* While run_dax() is potentially a generic operation that could be
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* defined in include/linux/dax.h we don't want to grow any users
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* outside of drivers/dax/
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*/
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void run_dax(struct dax_device *dax_dev);
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#define MODULE_ALIAS_DAX_DEVICE(type) \
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MODULE_ALIAS("dax:t" __stringify(type) "*")
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#define DAX_DEVICE_MODALIAS_FMT "dax:t%d"
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#endif /* __DAX_BUS_H__ */
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