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It is now allowed to use persistent memory like a regular RAM, but currently there is no way to remove this memory until machine is rebooted. This work expands the functionality to also allows hotremoving previously hotplugged persistent memory, and recover the device for use for other purposes. To hotremove persistent memory, the management software must first offline all memory blocks of dax region, and than unbind it from device-dax/kmem driver. So, operations should look like this: echo offline > /sys/devices/system/memory/memoryN/state ... echo dax0.0 > /sys/bus/dax/drivers/kmem/unbind Note: if unbind is done without offlining memory beforehand, it won't be possible to do dax0.0 hotremove, and dax's memory is going to be part of System RAM until reboot. Link: http://lkml.kernel.org/r/20190517215438.6487-4-pasha.tatashin@soleen.com Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: James Morris <jmorris@namei.org> Cc: Sasha Levin <sashal@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Keith Busch <keith.busch@intel.com> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Ross Zwisler <zwisler@kernel.org> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Fengguang Wu <fengguang.wu@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Yaowei Bai <baiyaowei@cmss.chinamobile.com> Cc: Takashi Iwai <tiwai@suse.de> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Dave Hansen <dave.hansen@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
61 lines
1.7 KiB
C
61 lines
1.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Copyright(c) 2016 Intel Corporation. All rights reserved.
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*/
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#ifndef __DAX_PRIVATE_H__
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#define __DAX_PRIVATE_H__
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#include <linux/device.h>
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#include <linux/cdev.h>
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/* private routines between core files */
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struct dax_device;
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struct dax_device *inode_dax(struct inode *inode);
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struct inode *dax_inode(struct dax_device *dax_dev);
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int dax_bus_init(void);
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void dax_bus_exit(void);
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/**
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* struct dax_region - mapping infrastructure for dax devices
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* @id: kernel-wide unique region for a memory range
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* @target_node: effective numa node if this memory range is onlined
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* @kref: to pin while other agents have a need to do lookups
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* @dev: parent device backing this region
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* @align: allocation and mapping alignment for child dax devices
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* @res: physical address range of the region
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* @pfn_flags: identify whether the pfns are paged back or not
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*/
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struct dax_region {
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int id;
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int target_node;
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struct kref kref;
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struct device *dev;
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unsigned int align;
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struct resource res;
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unsigned long pfn_flags;
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};
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/**
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* struct dev_dax - instance data for a subdivision of a dax region, and
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* data while the device is activated in the driver.
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* @region - parent region
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* @dax_dev - core dax functionality
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* @target_node: effective numa node if dev_dax memory range is onlined
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* @dev - device core
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* @pgmap - pgmap for memmap setup / lifetime (driver owned)
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* @dax_mem_res: physical address range of hotadded DAX memory
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*/
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struct dev_dax {
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struct dax_region *region;
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struct dax_device *dax_dev;
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int target_node;
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struct device dev;
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struct dev_pagemap pgmap;
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struct resource *dax_kmem_res;
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};
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static inline struct dev_dax *to_dev_dax(struct device *dev)
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{
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return container_of(dev, struct dev_dax, dev);
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}
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#endif
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