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60e93dc097
Break the requirement that device-dax instances are physically contiguous. With this constraint removed it allows fragmented available capacity to be fully allocated. This capability is useful to mitigate the "noisy neighbor" problem with memory-side-cache management for virtual machines, or any other scenario where a platform address boundary also designates a performance boundary. For example a direct mapped memory side cache might rotate cache colors at 1GB boundaries. With dis-contiguous allocations a device-dax instance could be configured to contain only 1 cache color. It also satisfies Joao's use case (see link) for partitioning memory for exclusive guest access. It allows for a future potential mode where the host kernel need not allocate 'struct page' capacity up-front. Reported-by: Joao Martins <joao.m.martins@oracle.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Ben Skeggs <bskeggs@redhat.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Brice Goglin <Brice.Goglin@inria.fr> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: David Airlie <airlied@linux.ie> Cc: David Hildenbrand <david@redhat.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Hulk Robot <hulkci@huawei.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Jason Gunthorpe <jgg@mellanox.com> Cc: Jason Yan <yanaijie@huawei.com> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: "Jérôme Glisse" <jglisse@redhat.com> Cc: Jia He <justin.he@arm.com> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com> Cc: Juergen Gross <jgross@suse.com> Cc: kernel test robot <lkp@intel.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Paul Mackerras <paulus@ozlabs.org> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Wei Yang <richard.weiyang@linux.alibaba.com> Cc: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/lkml/20200110190313.17144-1-joao.m.martins@oracle.com/ Link: https://lkml.kernel.org/r/159643104304.4062302.16561669534797528660.stgit@dwillia2-desk3.amr.corp.intel.com Link: https://lkml.kernel.org/r/160106116875.30709.11456649969327399771.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
74 lines
2.0 KiB
C
74 lines
2.0 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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#include <linux/idr.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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* @ida: instance id allocator
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* @res: resource tree to track instance allocations
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* @seed: allow userspace to find the first unbound seed device
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* @youngest: allow userspace to find the most recently created device
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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 ida ida;
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struct resource res;
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struct device *seed;
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struct device *youngest;
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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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* @id: ida allocated id
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* @dev - device core
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* @pgmap - pgmap for memmap setup / lifetime (driver owned)
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* @nr_range: size of @ranges
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* @ranges: resource-span + pgoff tuples for the instance
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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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int id;
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struct device dev;
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struct dev_pagemap *pgmap;
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int nr_range;
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struct dev_dax_range {
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unsigned long pgoff;
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struct range range;
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} *ranges;
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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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