Changes since v5 [1]: - (David) Introduce range_len() to include/linux/range.h immediately in "device-dax: make pgmap optional for instance creation" rather than wait until "mm/memremap_pages: convert to 'struct range'" to move it. - (David) David points out that release_mem_region() can not be used in the kmem driver since it depends on the resource range being busy at free. The dance the driver does to hand-off busy/free management to add_memory_driver_managed() breaks request_mem_region()'s assumptions and requires the driver to continue to use a open-coded release_resource() + kfree() sequence. For the new multi-range case, expand the driver-data to hold all the resulting 'struct resource' instances from mapping the ranges. - (Boris) consolidate pgmap manipulation code in the xen_alloc_unpopulated_pages() path. Since this touched "mm/memremap_pages: convert to 'struct range'" with the pending fix from Dan, I folded in that fix and gave him a Reported-by credit. [1]: http://lore.kernel.org/r/160106109960.30709.7379926726669669398.stgit@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx --- Hi Andrew, As before patches that are in your tree and did not change as a result of these updates are not re-sent. This set replaces: device-dax-make-pgmap-optional-for-instance-creation.patch ...through... device-dax-add-dis-contiguous-resource-support.patch ...in your stack. I let this soak over the weekend in kbuild-robot visible tree and it received a build success notification over 160 configs, and no other regression notices. --- 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 [2]. 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 [3] along cache-color boundaries. 3/ Parcel out soft-reserved memory to VMs using device-dax as a security / permissions boundary [4]. 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/157309097008.1579826.12818463304589384434.stgit@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx [3]: http://lore.kernel.org/r/154899811738.3165233.12325692939590944259.stgit@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx [4]: http://lore.kernel.org/r/20200110190313.17144-1-joao.m.martins@xxxxxxxxxx --- Dan Williams (11): device-dax: make pgmap optional for instance creation device-dax/kmem: introduce dax_kmem_range() device-dax/kmem: move resource tracking to drvdata device-dax: add an allocation interface for device-dax instances device-dax: introduce 'struct dev_dax' typed-driver operations 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 arch/powerpc/kvm/book3s_hv_uvmem.c | 14 - drivers/base/core.c | 2 drivers/dax/bus.c | 708 ++++++++++++++++++++++++++++++-- drivers/dax/bus.h | 11 drivers/dax/dax-private.h | 23 + drivers/dax/device.c | 71 ++- drivers/dax/hmem/hmem.c | 14 - drivers/dax/kmem.c | 198 ++++++--- drivers/dax/pmem/compat.c | 2 drivers/dax/pmem/core.c | 14 - 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 - drivers/xen/unpopulated-alloc.c | 49 +- include/linux/memremap.h | 11 include/linux/range.h | 6 lib/test_hmm.c | 51 +- mm/memremap.c | 299 ++++++++------ tools/testing/nvdimm/dax-dev.c | 22 + tools/testing/nvdimm/test/iomap.c | 2 25 files changed, 1216 insertions(+), 411 deletions(-) base-commit: d524ed85683d657593ac1e58098407bed0601a84
