Changes since v2 [1]: - Rebase on next/master to resolve conflicts with pending mem-hotplug and memremap_pages() changes in -mm
- Drop attempt at a generic phys_to_target_node() implementation and just follow the default fallback approach taken with memory_add_physaddr_to_nid() (Mike)
- Fix test_hmm and other compilation fixups (Ralph)
- Integrate Joao's extensions to the device-dax sub-division interface (per-device align, user-directed extent allocation). (Joao)
[1]: http://lore.kernel.org/r/159457116473.754248.7879464730875147365.stgit@dwill...
--- Merge notes:
Andrew, this series is rebased on today's next/master to resolve conflicts with some pending patches in -mm. I'd like to take it through your tree given the intersections with memremap_pages() and memory hotplug. If at all possible I'd like to see it in v5.10, but I realize time is short. Outside of the Intel identified use cases for this Joao has identified a use case for Oracle as well.
I would have sent this earlier save for the fact I am mostly offline tending to a newborn these days. Vishal has stepped up to take on care and feeding of this patchset if additional review / integration fixups are needed.
The one test feedback this wants is from Justin (justin.he@arm.com), and whether this lights up dax_kmem and now dax_hmem for him on arm64. Otherwise, Joao has written unit tests for this in his enabling of the daxctl userspace utility [2].
--- Cover:
The device-dax facility allows an address range to be directly mapped through a chardev, or optionally hotplugged to the core kernel page allocator as System-RAM. It is the mechanism for converting persistent memory (pmem) to be used as another volatile memory pool i.e. the current Memory Tiering hot topic on linux-mm.
In the case of pmem the nvdimm-namespace-label mechanism can sub-divide it, but that labeling mechanism is not available / applicable to soft-reserved ("EFI specific purpose") memory [3]. This series provides a sysfs-mechanism for the daxctl utility to enable provisioning of volatile-soft-reserved memory ranges.
The motivations for this facility are:
1/ Allow performance differentiated memory ranges to be split between kernel-managed and directly-accessed use cases.
2/ Allow physical memory to be provisioned along performance relevant address boundaries. For example, divide a memory-side cache [4] along cache-color boundaries.
3/ Parcel out soft-reserved memory to VMs using device-dax as a security / permissions boundary [5]. Specifically I have seen people (ab)using memmap=nn!ss (mark System-RAM as Persistent Memory) just to get the device-dax interface on custom address ranges. A follow-on for the VM use case is to teach device-dax to dynamically allocate 'struct page' at runtime to reduce the duplication of 'struct page' space in both the guest and the host kernel for the same physical pages.
[2]: http://lore.kernel.org/r/20200713160837.13774-11-joao.m.martins@oracle.com [3]: http://lore.kernel.org/r/157309097008.1579826.12818463304589384434.stgit@dwi... [4]: http://lore.kernel.org/r/154899811738.3165233.12325692939590944259.stgit@dwi... [5]: http://lore.kernel.org/r/20200110190313.17144-1-joao.m.martins@oracle.com
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Dan Williams (19): x86/numa: Cleanup configuration dependent command-line options x86/numa: Add 'nohmat' option efi/fake_mem: Arrange for a resource entry per efi_fake_mem instance ACPI: HMAT: Refactor hmat_register_target_device to hmem_register_device resource: Report parent to walk_iomem_res_desc() callback mm/memory_hotplug: Introduce default phys_to_target_node() implementation ACPI: HMAT: Attach a device for each soft-reserved range device-dax: Drop the dax_region.pfn_flags attribute device-dax: Move instance creation parameters to 'struct dev_dax_data' device-dax: Make pgmap optional for instance creation device-dax: Kill dax_kmem_res device-dax: Add an allocation interface for device-dax instances device-dax: Introduce 'seed' devices drivers/base: Make device_find_child_by_name() compatible with sysfs inputs device-dax: Add resize support mm/memremap_pages: Convert to 'struct range' mm/memremap_pages: Support multiple ranges per invocation device-dax: Add dis-contiguous resource support device-dax: Introduce 'mapping' devices
Joao Martins (4): device-dax: Make align a per-device property device-dax: Add an 'align' attribute dax/hmem: Introduce dax_hmem.region_idle parameter device-dax: Add a range mapping allocation attribute
arch/powerpc/kvm/book3s_hv_uvmem.c | 14 arch/x86/include/asm/numa.h | 8 arch/x86/kernel/e820.c | 16 arch/x86/mm/numa.c | 11 arch/x86/mm/numa_emulation.c | 3 arch/x86/xen/enlighten_pv.c | 2 drivers/acpi/numa/hmat.c | 76 -- drivers/acpi/numa/srat.c | 9 drivers/base/core.c | 2 drivers/dax/Kconfig | 4 drivers/dax/Makefile | 3 drivers/dax/bus.c | 1055 ++++++++++++++++++++++++++++++-- drivers/dax/bus.h | 28 + drivers/dax/dax-private.h | 40 + drivers/dax/device.c | 132 ++-- drivers/dax/hmem.c | 56 -- drivers/dax/hmem/Makefile | 6 drivers/dax/hmem/device.c | 100 +++ drivers/dax/hmem/hmem.c | 65 ++ drivers/dax/kmem.c | 199 +++--- drivers/dax/pmem/compat.c | 2 drivers/dax/pmem/core.c | 22 - drivers/firmware/efi/x86_fake_mem.c | 12 drivers/gpu/drm/nouveau/nouveau_dmem.c | 15 drivers/nvdimm/badrange.c | 26 - drivers/nvdimm/claim.c | 13 drivers/nvdimm/nd.h | 3 drivers/nvdimm/pfn_devs.c | 13 drivers/nvdimm/pmem.c | 27 - drivers/nvdimm/region.c | 21 - drivers/pci/p2pdma.c | 12 include/acpi/acpi_numa.h | 14 include/linux/dax.h | 8 include/linux/memory_hotplug.h | 5 include/linux/memremap.h | 11 include/linux/range.h | 6 kernel/resource.c | 11 lib/test_hmm.c | 15 mm/memory_hotplug.c | 10 mm/memremap.c | 299 +++++---- tools/testing/nvdimm/dax-dev.c | 22 - tools/testing/nvdimm/test/iomap.c | 2 42 files changed, 1810 insertions(+), 588 deletions(-) delete mode 100644 drivers/dax/hmem.c create mode 100644 drivers/dax/hmem/Makefile create mode 100644 drivers/dax/hmem/device.c create mode 100644 drivers/dax/hmem/hmem.c
base-commit: 01830e6c042e8eb6eb202e05d7df8057135b4c26