kernel/linux.git/drivers/dax/kmem.c, branch v7.0.10

Convert 'alloc_flex' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51+00:00

This is the exact same thing as the 'alloc_obj()' version, only much smaller because there are a lot fewer users of the *alloc_flex() interface. As with alloc_obj() version, this was done entirely with mindless brute force, using the same script, except using 'flex' in the pattern rather than 'objs*'. Signed-off-by: Linus Torvalds

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28+00:00

This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook

mm: remove callers of pfn_t functionality

2025-07-10T05:42:19+00:00

All PFN_* pfn_t flags have been removed. Therefore there is no longer a need for the pfn_t type and all uses can be replaced with normal pfns. Link: https://lkml.kernel.org/r/bbedfa576c9822f8032494efbe43544628698b1f.1750323463.git-series.apopple@nvidia.com Signed-off-by: Alistair Popple Reviewed-by: Christoph Hellwig Reviewed-by: Jason Gunthorpe Acked-by: David Hildenbrand Cc: Balbir Singh Cc: Björn Töpel Cc: Björn Töpel Cc: Chunyan Zhang Cc: Dan Williams Cc: Deepak Gupta Cc: Gerald Schaefer Cc: Inki Dae Cc: John Groves Cc: John Hubbard Cc: Lorenzo Stoakes Cc: Matthew Wilcox (Oracle) Cc: Will Deacon Signed-off-by: Andrew Morton

DAX: warn when kmem regions are truncated for memory block alignment

2025-05-13T06:50:49+00:00

Device capacity intended for use as system ram should be aligned to the architecture-defined memory block size or that capacity will be silently truncated and capacity stranded. As hotplug dax memory becomes more prevelant, the memory block size alignment becomes more important for platform and device vendors to pay attention to - so this truncation should not be silent. This issue is particularly relevant for CXL Dynamic Capacity devices, whose capacity may arrive in spec-aligned but block-misaligned chunks. Link: https://lkml.kernel.org/r/20250410142831.217887-1-gourry@gourry.net Suggested-by: David Hildenbrand Suggested-by: Dan Williams Reviewed-by: Dan Williams Tested-by: Alison Schofield Reviewed-by: Jonathan Cameron Acked-by: David Hildenbrand Signed-off-by: Gregory Price Cc: Dave Jiang Cc: Vishal Verma Signed-off-by: Andrew Morton

dax: add missing MODULE_DESCRIPTION() macros

2024-06-17T23:42:16+00:00

make allmodconfig && make W=1 C=1 reports: WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/dax/hmem/dax_hmem.o WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/dax/device_dax.o WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/dax/kmem.o WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/dax/dax_pmem.o WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/dax/dax_cxl.o Add all missing invocations of the MODULE_DESCRIPTION() macro. [iweiny: edit descriptions] Signed-off-by: Jeff Johnson Link: https://patch.msgid.link/r/20240605-md-drivers-dax-v1-1-3d448f3368b4@quicinc.com Signed-off-by: Ira Weiny

memory tier: dax/kmem: introduce an abstract layer for finding, allocating, and putting memory types

2024-05-06T00:53:25+00:00

Patch series "Improved Memory Tier Creation for CPUless NUMA Nodes", v11. When a memory device, such as CXL1.1 type3 memory, is emulated as normal memory (E820_TYPE_RAM), the memory device is indistinguishable from normal DRAM in terms of memory tiering with the current implementation. The current memory tiering assigns all detected normal memory nodes to the same DRAM tier. This results in normal memory devices with different attributions being unable to be assigned to the correct memory tier, leading to the inability to migrate pages between different types of memory. https://lore.kernel.org/linux-mm/PH0PR08MB7955E9F08CCB64F23963B5C3A860A@PH0PR08MB7955.namprd08.prod.outlook.com/T/ This patchset automatically resolves the issues. It delays the initialization of memory tiers for CPUless NUMA nodes until they obtain HMAT information and after all devices are initialized at boot time, eliminating the need for user intervention. If no HMAT is specified, it falls back to using `default_dram_type`. Example usecase: We have CXL memory on the host, and we create VMs with a new system memory device backed by host CXL memory. We inject CXL memory performance attributes through QEMU, and the guest now sees memory nodes with performance attributes in HMAT. With this change, we enable the guest kernel to construct the correct memory tiering for the memory nodes. This patch (of 2): Since different memory devices require finding, allocating, and putting memory types, these common steps are abstracted in this patch, enhancing the scalability and conciseness of the code. Link: https://lkml.kernel.org/r/20240405000707.2670063-1-horenchuang@bytedance.com Link: https://lkml.kernel.org/r/20240405000707.2670063-2-horenchuang@bytedance.com Signed-off-by: Ho-Ren (Jack) Chuang Reviewed-by: "Huang, Ying" Reviewed-by: Jonathan Cameron Cc: Alistair Popple Cc: Aneesh Kumar K.V Cc: Dan Williams Cc: Dave Jiang Cc: Gregory Price Cc: Hao Xiang Cc: Jonathan Cameron Cc: Michal Hocko Cc: Ravi Jonnalagadda Cc: SeongJae Park Cc: Tejun Heo Cc: Vishal Verma Signed-off-by: Andrew Morton

dax/kmem: allow kmem to add memory with memmap_on_memory

2023-12-11T00:51:35+00:00

Large amounts of memory managed by the kmem driver may come in via CXL, and it is often desirable to have the memmap for this memory on the new memory itself. Enroll kmem-managed memory for memmap_on_memory semantics if the dax region originates via CXL. For non-CXL dax regions, retain the existing default behavior of hot adding without memmap_on_memory semantics. Link: https://lkml.kernel.org/r/20231107-vv-kmem_memmap-v10-3-1253ec050ed0@intel.com Signed-off-by: Vishal Verma Reviewed-by: Jonathan Cameron Reviewed-by: David Hildenbrand Reviewed-by: "Huang, Ying" Tested-by: Li Zhijian [cxl.kmem and nvdimm.kmem] Cc: Michal Hocko Cc: Oscar Salvador Cc: Dan Williams Cc: Dave Jiang Cc: Dave Hansen Cc: Aneesh Kumar K.V Cc: Fan Ni Cc: Jeff Moyer Signed-off-by: Andrew Morton

dax, kmem: calculate abstract distance with general interface

2023-10-16T22:44:39+00:00

Previously, a fixed abstract distance MEMTIER_DEFAULT_DAX_ADISTANCE is used for slow memory type in kmem driver. This limits the usage of kmem driver, for example, it cannot be used for HBM (high bandwidth memory). So, we use the general abstract distance calculation mechanism in kmem drivers to get more accurate abstract distance on systems with proper support. The original MEMTIER_DEFAULT_DAX_ADISTANCE is used as fallback only. Now, multiple memory types may be managed by kmem. These memory types are put into the "kmem_memory_types" list and protected by kmem_memory_type_lock. Link: https://lkml.kernel.org/r/20230926060628.265989-5-ying.huang@intel.com Signed-off-by: "Huang, Ying" Tested-by: Bharata B Rao Reviewed-by: Dave Jiang Reviewed-by: Alistair Popple Cc: Aneesh Kumar K.V Cc: Wei Xu Cc: Dan Williams Cc: Dave Hansen Cc: Davidlohr Bueso Cc: Johannes Weiner Cc: Jonathan Cameron Cc: Michal Hocko Cc: Yang Shi Cc: Rafael J Wysocki Signed-off-by: Andrew Morton

memory tier: rename destroy_memory_type() to put_memory_type()

2023-08-18T17:12:11+00:00

It appears that destroy_memory_type() isn't a very good name because we usually will not free the memory_type here. So rename it to a more appropriate name i.e. put_memory_type(). Link: https://lkml.kernel.org/r/20230706063905.543800-1-linmiaohe@huawei.com Signed-off-by: Miaohe Lin Suggested-by: Huang, Ying Reviewed-by: "Huang, Ying" Reviewed-by: Xiao Yang Cc: Dan Williams Cc: Dave Jiang Cc: Vishal Verma Signed-off-by: Andrew Morton

dax/kmem: Pass valid argument to memory_group_register_static

2023-06-23T07:32:06+00:00

memory_group_register_static takes maximum number of pages as the argument while dev_dax_kmem_probe passes total_len (in bytes) as the argument. IIUC, I don't see any crash/panic impact as such. As, memory_group_register_static just set the max_pages limit which is used in auto_movable_zone_for_pfn to determine the zone. which might cause these condition to behave differently, This will be true always so jump will happen to kernel_zone ... if (!auto_movable_can_online_movable(NUMA_NO_NODE, group, nr_pages)) goto kernel_zone; ... kernel_zone: return default_kernel_zone_for_pfn(nid, pfn, nr_pages); Here, In below, zone_intersects compare range will be larger as nr_pages will be higher (derived from total_len passed in dev_dax_kmem_probe). ... static struct zone *default_kernel_zone_for_pfn(int nid, unsigned long start_pfn, unsigned long nr_pages) { struct pglist_data *pgdat = NODE_DATA(nid); int zid; for (zid = 0; zid < ZONE_NORMAL; zid++) { struct zone *zone = &pgdat->node_zones[zid]; if (zone_intersects(zone, start_pfn, nr_pages)) return zone; } return &pgdat->node_zones[ZONE_NORMAL]; } Incorrect zone will be returned here, which in later time might cause bigger problem. Fixes: eedf634aac3b ("dax/kmem: use a single static memory group for a single probed unit") Signed-off-by: Tarun Sahu Link: https://lore.kernel.org/r/20230621155025.370672-1-tsahu@linux.ibm.com Reviewed-by: Vishal Verma Signed-off-by: Vishal Verma