kernel/linux.git/drivers/dax/Kconfig, branch v6.12.80

mm: make range-to-target_node lookup facility a part of numa_memblks

2024-09-04T04:15:32+00:00

The x86 implementation of range-to-target_node lookup (i.e. phys_to_target_node() and memory_add_physaddr_to_nid()) relies on numa_memblks. Since numa_memblks are now part of the generic code, move these functions from x86 to mm/numa_memblks.c and select CONFIG_NUMA_KEEP_MEMINFO when CONFIG_NUMA_MEMBLKS=y for dax and cxl. [rppt@kernel.org: fix build] Link: https://lkml.kernel.org/r/ZtVfSt_zloPdDqVB@kernel.org Link: https://lkml.kernel.org/r/20240807064110.1003856-26-rppt@kernel.org Signed-off-by: Mike Rapoport (Microsoft) Reviewed-by: Jonathan Cameron Tested-by: Zi Yan # for x86_64 and arm64 Tested-by: Jonathan Cameron [arm64 + CXL via QEMU] Reviewed-by: Dan Williams Acked-by: David Hildenbrand Cc: Alexander Gordeev Cc: Andreas Larsson Cc: Arnd Bergmann Cc: Borislav Petkov Cc: Catalin Marinas Cc: Christophe Leroy Cc: Dave Hansen Cc: Davidlohr Bueso Cc: David S. Miller Cc: Greg Kroah-Hartman Cc: Heiko Carstens Cc: Huacai Chen Cc: Ingo Molnar Cc: Jiaxun Yang Cc: John Paul Adrian Glaubitz Cc: Jonathan Corbet Cc: Michael Ellerman Cc: Palmer Dabbelt Cc: Rafael J. Wysocki Cc: Rob Herring (Arm) Cc: Samuel Holland Cc: Thomas Bogendoerfer Cc: Thomas Gleixner Cc: Vasily Gorbik Cc: Will Deacon Signed-off-by: Andrew Morton

Merge tag 'cxl-for-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl

2023-02-25T17:19:23+00:00

Pull Compute Express Link (CXL) updates from Dan Williams: "To date Linux has been dependent on platform-firmware to map CXL RAM regions and handle events / errors from devices. With this update we can now parse / update the CXL memory layout, and report events / errors from devices. This is a precursor for the CXL subsystem to handle the end-to-end "RAS" flow for CXL memory. i.e. the flow that for DDR-attached-DRAM is handled by the EDAC driver where it maps system physical address events to a field-replaceable-unit (FRU / endpoint device). In general, CXL has the potential to standardize what has historically been a pile of memory-controller-specific error handling logic. Another change of note is the default policy for handling RAM-backed device-dax instances. Previously the default access mode was "device", mmap(2) a device special file to access memory. The new default is "kmem" where the address range is assigned to the core-mm via add_memory_driver_managed(). This saves typical users from wondering why their platform memory is not visible via free(1) and stuck behind a device-file. At the same time it allows expert users to deploy policy to, for example, get dedicated access to high performance memory, or hide low performance memory from general purpose kernel allocations. This affects not only CXL, but also systems with high-bandwidth-memory that platform-firmware tags with the EFI_MEMORY_SP (special purpose) designation. Summary: - CXL RAM region enumeration: instantiate 'struct cxl_region' objects for platform firmware created memory regions - CXL RAM region provisioning: complement the existing PMEM region creation support with RAM region support - "Soft Reservation" policy change: Online (memory hot-add) soft-reserved memory (EFI_MEMORY_SP) by default, but still allow for setting aside such memory for dedicated access via device-dax. - CXL Events and Interrupts: Takeover CXL event handling from platform-firmware (ACPI calls this CXL Memory Error Reporting) and export CXL Events via Linux Trace Events. - Convey CXL _OSC results to drivers: Similar to PCI, let the CXL subsystem interrogate the result of CXL _OSC negotiation. - Emulate CXL DVSEC Range Registers as "decoders": Allow for first-generation devices that pre-date the definition of the CXL HDM Decoder Capability to translate the CXL DVSEC Range Registers into 'struct cxl_decoder' objects. - Set timestamp: Per spec, set the device timestamp in case of hotplug, or if platform-firwmare failed to set it. - General fixups: linux-next build issues, non-urgent fixes for pre-production hardware, unit test fixes, spelling and debug message improvements" * tag 'cxl-for-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl: (66 commits) dax/kmem: Fix leak of memory-hotplug resources cxl/mem: Add kdoc param for event log driver state cxl/trace: Add serial number to trace points cxl/trace: Add host output to trace points cxl/trace: Standardize device information output cxl/pci: Remove locked check for dvsec_range_allowed() cxl/hdm: Add emulation when HDM decoders are not committed cxl/hdm: Create emulated cxl_hdm for devices that do not have HDM decoders cxl/hdm: Emulate HDM decoder from DVSEC range registers cxl/pci: Refactor cxl_hdm_decode_init() cxl/port: Export cxl_dvsec_rr_decode() to cxl_port cxl/pci: Break out range register decoding from cxl_hdm_decode_init() cxl: add RAS status unmasking for CXL cxl: remove unnecessary calling of pci_enable_pcie_error_reporting() dax/hmem: build hmem device support as module if possible dax: cxl: add CXL_REGION dependency cxl: avoid returning uninitialized error code cxl/pmem: Fix nvdimm registration races cxl/mem: Fix UAPI command comment cxl/uapi: Tag commands from cxl_query_cmd() ...

dax: cxl: add CXL_REGION dependency

2023-02-14T16:38:20+00:00

There is already a dependency on CXL_REGION, which depends on CXL_BUS, but since CXL_REGION is a 'bool' symbol, it's possible to configure DAX as built-in even though CXL itself is a loadable module: x86_64-linux-ld: drivers/dax/cxl.o: in function `cxl_dax_region_probe': cxl.c:(.text+0xb): undefined reference to `to_cxl_dax_region' x86_64-linux-ld: drivers/dax/cxl.o: in function `cxl_dax_region_driver_init': cxl.c:(.init.text+0x10): undefined reference to `__cxl_driver_register' x86_64-linux-ld: drivers/dax/cxl.o: in function `cxl_dax_region_driver_exit': cxl.c:(.exit.text+0x9): undefined reference to `cxl_driver_unregister' Prevent this with another depndency on the tristate symbol. Fixes: 09d09e04d2fc ("cxl/dax: Create dax devices for CXL RAM regions") Signed-off-by: Arnd Bergmann Link: https://lore.kernel.org/r/20230214103054.1082908-1-arnd@kernel.org Signed-off-by: Dan Williams

cxl/dax: Create dax devices for CXL RAM regions

2023-02-11T01:33:45+00:00

While platform firmware takes some responsibility for mapping the RAM capacity of CXL devices present at boot, the OS is responsible for mapping the remainder and hot-added devices. Platform firmware is also responsible for identifying the platform general purpose memory pool, typically DDR attached DRAM, and arranging for the remainder to be 'Soft Reserved'. That reservation allows the CXL subsystem to route the memory to core-mm via memory-hotplug (dax_kmem), or leave it for dedicated access (device-dax). The new 'struct cxl_dax_region' object allows for a CXL memory resource (region) to be published, but also allow for udev and module policy to act on that event. It also prevents cxl_core.ko from having a module loading dependency on any drivers/dax/ modules. Tested-by: Fan Ni Reviewed-by: Dave Jiang Reviewed-by: Jonathan Cameron Link: https://lore.kernel.org/r/167602003896.1924368.10335442077318970468.stgit@dwillia2-xfh.jf.intel.com Signed-off-by: Dan Williams

dax: Assign RAM regions to memory-hotplug by default

2023-02-11T01:33:40+00:00

The default mode for device-dax instances is backwards for RAM-regions as evidenced by the fact that it tends to catch end users by surprise. "Where is my memory?". Recall that platforms are increasingly shipping with performance-differentiated memory pools beyond typical DRAM and NUMA effects. This includes HBM (high-bandwidth-memory) and CXL (dynamic interleave, varied media types, and future fabric attached possibilities). For this reason the EFI_MEMORY_SP (EFI Special Purpose Memory => Linux 'Soft Reserved') attribute is expected to be applied to all memory-pools that are not the general purpose pool. This designation gives an Operating System a chance to defer usage of a memory pool until later in the boot process where its performance properties can be interrogated and administrator policy can be applied. 'Soft Reserved' memory can be anything from too limited and precious to be part of the general purpose pool (HBM), too slow to host hot kernel data structures (some PMEM media), or anything in between. However, in the absence of an explicit policy, the memory should at least be made usable by default. The current device-dax default hides all non-general-purpose memory behind a device interface. The expectation is that the distribution of users that want the memory online by default vs device-dedicated-access by default follows the Pareto principle. A small number of enlightened users may want to do userspace memory management through a device, but general users just want the kernel to make the memory available with an option to get more advanced later. Arrange for all device-dax instances not backed by PMEM to default to attaching to the dax_kmem driver. From there the baseline memory hotplug policy (CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE / memhp_default_state=) gates whether the memory comes online or stays offline. Where, if it stays offline, it can be reliably converted back to device-mode where it can be partitioned, or fronted by a userspace allocator. So, if someone wants device-dax instances for their 'Soft Reserved' memory: 1/ Build a kernel with CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE=n or boot with memhp_default_state=offline, or roll the dice and hope that the kernel has not pinned a page in that memory before step 2. 2/ Write a udev rule to convert the target dax device(s) from 'system-ram' mode to 'devdax' mode: daxctl reconfigure-device $dax -m devdax -f Cc: Michal Hocko Cc: David Hildenbrand Cc: Dave Hansen Reviewed-by: Gregory Price Tested-by: Fan Ni Reviewed-by: Dave Jiang Link: https://lore.kernel.org/r/167602003336.1924368.6809503401422267885.stgit@dwillia2-xfh.jf.intel.com Signed-off-by: Dan Williams

dax/hmem: Move hmem device registration to dax_hmem.ko

2023-02-11T01:33:34+00:00

In preparation for the CXL region driver to take over the responsibility of registering device-dax instances for CXL regions, move the registration of "hmem" devices to dax_hmem.ko. Previously the builtin component of this enabling (drivers/dax/hmem/device.o) would register platform devices for each address range and trigger the dax_hmem.ko module to load and attach device-dax instances to those devices. Now, the ranges are collected from the HMAT and EFI memory map walking, but the device creation is deferred. A new "hmem_platform" device is created which triggers dax_hmem.ko to load and register the platform devices. Tested-by: Fan Ni Reviewed-by: Dave Jiang Reviewed-by: Jonathan Cameron Link: https://lore.kernel.org/r/167602002771.1924368.5653558226424530127.stgit@dwillia2-xfh.jf.intel.com Signed-off-by: Dan Williams

drivers/dax: Remove "select SRCU"

2023-02-03T00:26:05+00:00

Now that the SRCU Kconfig option is unconditionally selected, there is no longer any point in selecting it. Therefore, remove the "select SRCU" Kconfig statements. Signed-off-by: Paul E. McKenney Cc: Dan Williams Cc: Vishal Verma Cc: Dave Jiang Cc: Acked-by: Dan Williams Reviewed-by: John Ogness

dax: remove CONFIG_DAX_DRIVER

2021-12-04T16:58:51+00:00

CONFIG_DAX_DRIVER only selects CONFIG_DAX now, so remove it. Signed-off-by: Christoph Hellwig Reviewed-by: Dan Williams Link: https://lore.kernel.org/r/20211129102203.2243509-4-hch@lst.de Signed-off-by: Dan Williams

dax: Kill DEV_DAX_PMEM_COMPAT

2021-11-25T03:21:35+00:00

The /sys/class/dax compatibility option has shipped in the kernel for 4 years now which should be sufficient time for tools to abandon the old ABI in favor of the /sys/bus/dax device-model. Delete it now and see if anyone screams. Since this compatibility option shipped there has been more reports of users being surprised by the compat ABI than surprised by the "new", so the compat infrastructure has outlived its usefulness. Recall that /sys/bus/dax device-model is required for the dax kmem driver which allows PMEM to be used as "System RAM". The following projects were known to have a dependency on /sys/class/dax and have dropped their dependency as of the listed version: - ndctl (including libndctl, daxctl, and libdaxctl): v64+ - fio: v3.13+ - pmdk: v1.5.2+ As further evidence this option is no longer needed some distributions have already stopped enabling CONFIG_DEV_DAX_PMEM_COMPAT. Cc: Ira Weiny Cc: Dave Jiang Reported-by: Vishal Verma Acked-by: Dave Hansen Reviewed-by: Jane Chu Link: https://lore.kernel.org/r/163701116195.3784476.726128179293466337.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams

mm: fix phys_to_target_node() and memory_add_physaddr_to_nid() exports

2020-11-22T18:48:22+00:00

The core-mm has a default __weak implementation of phys_to_target_node() to mirror the weak definition of memory_add_physaddr_to_nid(). That symbol is exported for modules. However, while the export in mm/memory_hotplug.c exported the symbol in the configuration cases of: CONFIG_NUMA_KEEP_MEMINFO=y CONFIG_MEMORY_HOTPLUG=y ...and: CONFIG_NUMA_KEEP_MEMINFO=n CONFIG_MEMORY_HOTPLUG=y ...it failed to export the symbol in the case of: CONFIG_NUMA_KEEP_MEMINFO=y CONFIG_MEMORY_HOTPLUG=n Not only is that broken, but Christoph points out that the kernel should not be exporting any __weak symbol, which means that memory_add_physaddr_to_nid() example that phys_to_target_node() copied is broken too. Rework the definition of phys_to_target_node() and memory_add_physaddr_to_nid() to not require weak symbols. Move to the common arch override design-pattern of an asm header defining a symbol to replace the default implementation. The only common header that all memory_add_physaddr_to_nid() producing architectures implement is asm/sparsemem.h. In fact, powerpc already defines its memory_add_physaddr_to_nid() helper in sparsemem.h. Double-down on that observation and define phys_to_target_node() where necessary in asm/sparsemem.h. An alternate consideration that was discarded was to put this override in asm/numa.h, but that entangles with the definition of MAX_NUMNODES relative to the inclusion of linux/nodemask.h, and requires powerpc to grow a new header. The dependency on NUMA_KEEP_MEMINFO for DEV_DAX_HMEM_DEVICES is invalid now that the symbol is properly exported / stubbed in all combinations of CONFIG_NUMA_KEEP_MEMINFO and CONFIG_MEMORY_HOTPLUG. [dan.j.williams@intel.com: v4] Link: https://lkml.kernel.org/r/160461461867.1505359.5301571728749534585.stgit@dwillia2-desk3.amr.corp.intel.com [dan.j.williams@intel.com: powerpc: fix create_section_mapping compile warning] Link: https://lkml.kernel.org/r/160558386174.2948926.2740149041249041764.stgit@dwillia2-desk3.amr.corp.intel.com Fixes: a035b6bf863e ("mm/memory_hotplug: introduce default phys_to_target_node() implementation") Reported-by: Randy Dunlap Reported-by: Thomas Gleixner Reported-by: kernel test robot Reported-by: Christoph Hellwig Signed-off-by: Dan Williams Signed-off-by: Andrew Morton Tested-by: Randy Dunlap Tested-by: Thomas Gleixner Reviewed-by: Thomas Gleixner Reviewed-by: Christoph Hellwig Cc: Joao Martins Cc: Tony Luck Cc: Fenghua Yu Cc: Michael Ellerman Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Vishal Verma Cc: Stephen Rothwell Link: https://lkml.kernel.org/r/160447639846.1133764.7044090803980177548.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Linus Torvalds