kernel/linux.git/include/linux/memory_hotplug.h, branch v6.19.11

mm/memory_hotplug: Remove MEM_PREPARE_ONLINE/MEM_FINISH_OFFLINE notifiers

2025-10-14T12:24:53+00:00

MEM_PREPARE_ONLINE/MEM_FINISH_OFFLINE memory notifiers were introduced to prepare the transition of memory to and from a physically accessible state. This enhancement was crucial for implementing the "memmap on memory" feature for s390. With introduction of dynamic (de)configuration of hotpluggable memory, memory can be brought to accessible state before add_memory(). Memory can be brought to inaccessible state before remove_memory(). Hence, there is no need of MEM_PREPARE_ONLINE/MEM_FINISH_OFFLINE memory notifiers anymore. This basically reverts commit c5f1e2d18909 ("mm/memory_hotplug: introduce MEM_PREPARE_ONLINE/MEM_FINISH_OFFLINE notifiers") Additionally, apply minor adjustments to the function parameters of move_pfn_range_to_zone() and mhp_supports_memmap_on_memory() to ensure compatibility with the latest branch. Acked-by: David Hildenbrand Signed-off-by: Sumanth Korikkar Signed-off-by: Heiko Carstens

mm/page_alloc: add support for initializing pageblock as isolated

2025-07-13T23:38:17+00:00

MIGRATE_ISOLATE is a standalone bit, so a pageblock cannot be initialized to just MIGRATE_ISOLATE. Add init_pageblock_migratetype() to enable initialize a pageblock with a migratetype and isolated. Link: https://lkml.kernel.org/r/20250617021115.2331563-4-ziy@nvidia.com Signed-off-by: Zi Yan Reviewed-by: Vlastimil Babka Acked-by: David Hildenbrand Cc: Baolin Wang Cc: Brendan Jackman Cc: Johannes Weiner Cc: Kirill A. Shuemov Cc: Mel Gorman Cc: Michal Hocko Cc: Oscar Salvador Cc: Richard Chang Cc: Suren Baghdasaryan Signed-off-by: Andrew Morton

mm: add build-time option for hotplug memory default online type

2025-01-26T04:22:21+00:00

Memory hotplug presently auto-onlines memory into a zone the kernel deems appropriate if CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE=y. The memhp_default_state boot param enables runtime config, but it's not possible to do this at build-time. Remove CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE, and replace it with CONFIG_MHP_DEFAULT_ONLINE_TYPE_* choices that sync with the boot param. Selections: CONFIG_MHP_DEFAULT_ONLINE_TYPE_OFFLINE => mhp_default_online_type = "offline" Memory will not be onlined automatically. CONFIG_MHP_DEFAULT_ONLINE_TYPE_ONLINE_AUTO => mhp_default_online_type = "online" Memory will be onlined automatically in a zone deemed. appropriate by the kernel. CONFIG_MHP_DEFAULT_ONLINE_TYPE_ONLINE_KERNEL => mhp_default_online_type = "online_kernel" Memory will be onlined automatically. The zone may allow kernel data (e.g. ZONE_NORMAL). CONFIG_MHP_DEFAULT_ONLINE_TYPE_ONLINE_MOVABLE => mhp_default_online_type = "online_movable" Memory will be onlined automatically. The zone will be ZONE_MOVABLE. Default to CONFIG_MHP_DEFAULT_ONLINE_TYPE_OFFLINE to match the existing default CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE=n behavior. Existing users of CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE=y should use CONFIG_MHP_DEFAULT_ONLINE_TYPE_ONLINE_AUTO. [gourry@gourry.net: update KConfig comments] Link: https://lkml.kernel.org/r/20241226182918.648799-1-gourry@gourry.net Link: https://lkml.kernel.org/r/20241220210709.300066-1-gourry@gourry.net Signed-off-by: Gregory Price Acked-by: David Hildenbrand Cc: Greg Kroah-Hartman Cc: Huacai Chen Cc: Jonathan Corbet Cc: Oscar Salvador Cc: "Rafael J. Wysocki" Cc: WANG Xuerui Signed-off-by: Andrew Morton

mm: drop CONFIG_HAVE_ARCH_NODEDATA_EXTENSION

2024-09-04T04:15:28+00:00

There are no users of HAVE_ARCH_NODEDATA_EXTENSION left, so arch_alloc_nodedata() and arch_refresh_nodedata() are not needed anymore. Replace the call to arch_alloc_nodedata() in free_area_init() with a new helper alloc_offline_node_data(), remove arch_refresh_nodedata() and cleanup include/linux/memory_hotplug.h from the associated ifdefery. Link: https://lkml.kernel.org/r/20240807064110.1003856-9-rppt@kernel.org Signed-off-by: Mike Rapoport (Microsoft) Tested-by: Zi Yan # for x86_64 and arm64 Acked-by: Dan Williams Cc: Alexander Gordeev Cc: Andreas Larsson Cc: Arnd Bergmann Cc: Borislav Petkov Cc: Catalin Marinas Cc: Christophe Leroy Cc: Dave Hansen Cc: David Hildenbrand 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 Cameron 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

mm/memory_hotplug: skip adjust_managed_page_count() for PageOffline() pages when offlining

2024-07-04T02:30:18+00:00

We currently have a hack for virtio-mem in place to handle memory offlining with PageOffline pages for which we already adjusted the managed page count. Let's enlighten memory offlining code so we can get rid of that hack, and document the situation. Link: https://lkml.kernel.org/r/20240607090939.89524-4-david@redhat.com Signed-off-by: David Hildenbrand Acked-by: Oscar Salvador Cc: Alexander Potapenko Cc: Dexuan Cui Cc: Dmitry Vyukov Cc: Eugenio Pérez Cc: Haiyang Zhang Cc: Jason Wang Cc: Juergen Gross Cc: "K. Y. Srinivasan" Cc: Marco Elver Cc: Michael S. Tsirkin Cc: Mike Rapoport (IBM) Cc: Oleksandr Tyshchenko Cc: Stefano Stabellini Cc: Wei Liu Cc: Xuan Zhuo Signed-off-by: Andrew Morton

mm/memory_hotplug: export mhp_supports_memmap_on_memory()

2024-02-22T18:24:40+00:00

In preparation for adding sysfs ABI to toggle memmap_on_memory semantics for drivers adding memory, export the mhp_supports_memmap_on_memory() helper. This allows drivers to check if memmap_on_memory support is available before trying to request it, and display an appropriate message if it isn't available. As part of this, remove the size argument to this - with recent updates to allow memmap_on_memory for larger ranges, and the internal splitting of altmaps into respective memory blocks, the size argument is meaningless. [akpm@linux-foundation.org: fix build] Link: https://lkml.kernel.org/r/20240124-vv-dax_abi-v7-4-20d16cb8d23d@intel.com Signed-off-by: Vishal Verma Acked-by: David Hildenbrand Suggested-by: David Hildenbrand Cc: Greg Kroah-Hartman Cc: Jonathan Cameron Cc: Li Zhijian Cc: Matthew Wilcox (Oracle) Cc: Michal Hocko Cc: Oscar Salvador Cc: Dan Williams Cc: Dave Jiang Cc: Dave Hansen Cc: Huang Ying Signed-off-by: Andrew Morton

mm/memory_hotplug: introduce MEM_PREPARE_ONLINE/MEM_FINISH_OFFLINE notifiers

2024-02-22T00:00:01+00:00

Patch series "implement "memmap on memory" feature on s390". This series provides "memmap on memory" support on s390 platform. "memmap on memory" allows struct pages array to be allocated from the hotplugged memory range instead of allocating it from main system memory. s390 currently preallocates struct pages array for all potentially possible memory, which ensures memory onlining always succeeds, but with the cost of significant memory consumption from the available system memory during boottime. In certain extreme configuration, this could lead to ipl failure. "memmap on memory" ensures struct pages array are populated from self contained hotplugged memory range instead of depleting the available system memory and this could eliminate ipl failure on s390 platform. On other platforms, system might go OOM when the physically hotplugged memory depletes the available memory before it is onlined. Hence, "memmap on memory" feature was introduced as described in commit a08a2ae34613 ("mm,memory_hotplug: allocate memmap from the added memory range"). Unlike other architectures, s390 memory blocks are not physically accessible until it is online. To make it physically accessible two new memory notifiers MEM_PREPARE_ONLINE / MEM_FINISH_OFFLINE are added and this notifier lets the hypervisor inform that the memory should be made physically accessible. This allows for "memmap on memory" initialization during memory hotplug onlining phase, which is performed before calling MEM_GOING_ONLINE notifier. Patch 1 introduces MEM_PREPARE_ONLINE/MEM_FINISH_OFFLINE memory notifiers to prepare the transition of memory to and from a physically accessible state. New mhp_flag MHP_OFFLINE_INACCESSIBLE is introduced to ensure altmap cannot be written when adding memory - before it is set online. This enhancement is crucial for implementing the "memmap on memory" feature for s390 in a subsequent patch. Patches 2 allocates vmemmap pages from self-contained memory range for s390. It allocates memory map (struct pages array) from the hotplugged memory range, rather than using system memory by passing altmap to vmemmap functions. Patch 3 removes unhandled memory notifier types on s390. Patch 4 implements MEM_PREPARE_ONLINE/MEM_FINISH_OFFLINE memory notifiers on s390. MEM_PREPARE_ONLINE memory notifier makes memory block physical accessible via sclp assign command. The notifier ensures self-contained memory maps are accessible and hence enabling the "memmap on memory" on s390. MEM_FINISH_OFFLINE memory notifier shifts the memory block to an inaccessible state via sclp unassign command. Patch 5 finally enables MHP_MEMMAP_ON_MEMORY on s390. This patch (of 5): Introduce MEM_PREPARE_ONLINE/MEM_FINISH_OFFLINE memory notifiers to prepare the transition of memory to and from a physically accessible state. This enhancement is crucial for implementing the "memmap on memory" feature for s390 in a subsequent patch. Platforms such as x86 can support physical memory hotplug via ACPI. When there is physical memory hotplug, ACPI event leads to the memory addition with the following callchain: acpi_memory_device_add() -> acpi_memory_enable_device() -> __add_memory() After this, the hotplugged memory is physically accessible, and altmap support prepared, before the "memmap on memory" initialization in memory_block_online() is called. On s390, memory hotplug works in a different way. The available hotplug memory has to be defined upfront in the hypervisor, but it is made physically accessible only when the user sets it online via sysfs, currently in the MEM_GOING_ONLINE notifier. This is too late and "memmap on memory" initialization is performed before calling MEM_GOING_ONLINE notifier. During the memory hotplug addition phase, altmap support is prepared and during the memory onlining phase s390 requires memory to be physically accessible and then subsequently initiate the "memmap on memory" initialization process. The memory provider will handle new MEM_PREPARE_ONLINE / MEM_FINISH_OFFLINE notifications and make the memory accessible. The mhp_flag MHP_OFFLINE_INACCESSIBLE is introduced and is relevant when used along with MHP_MEMMAP_ON_MEMORY, because the altmap cannot be written (e.g., poisoned) when adding memory -- before it is set online. This allows for adding memory with an altmap that is not currently made available by a hypervisor. When onlining that memory, the hypervisor can be instructed to make that memory accessible via the new notifiers and the onlining phase will not require any memory allocations, which is helpful in low-memory situations. All architectures ignore unknown memory notifiers. Therefore, the introduction of these new notifiers does not result in any functional modifications across architectures. Link: https://lkml.kernel.org/r/20240108132747.3238763-1-sumanthk@linux.ibm.com Link: https://lkml.kernel.org/r/20240108132747.3238763-2-sumanthk@linux.ibm.com Signed-off-by: Sumanth Korikkar Suggested-by: Gerald Schaefer Suggested-by: David Hildenbrand Acked-by: David Hildenbrand Cc: Alexander Gordeev Cc: Aneesh Kumar K.V Cc: Anshuman Khandual Cc: Heiko Carstens Cc: Michal Hocko Cc: Oscar Salvador Cc: Vasily Gorbik Signed-off-by: Andrew Morton

mm/memory_hotplug: allow memmap on memory hotplug request to fallback

2023-08-21T20:37:48+00:00

If not supported, fallback to not using memap on memmory. This avoids the need for callers to do the fallback. Link: https://lkml.kernel.org/r/20230808091501.287660-3-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V Acked-by: Michal Hocko Acked-by: David Hildenbrand Cc: Christophe Leroy Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Oscar Salvador Cc: Vishal Verma Signed-off-by: Andrew Morton

mm/sparse: remove unused parameters in sparse_remove_section()

2023-06-19T23:19:04+00:00

These parameters ms and map_offset are not used in sparse_remove_section(), so remove them. The __remove_section() is only called by __remove_pages(), remove it. And put the WARN_ON_ONCE() in sparse_remove_section(). Link: https://lkml.kernel.org/r/20230607023952.2247489-1-yajun.deng@linux.dev Signed-off-by: Yajun Deng Reviewed-by: David Hildenbrand Cc: Oscar Salvador Signed-off-by: Andrew Morton

mm: page_alloc: move set_zone_contiguous() into mm_init.c

2023-06-09T23:25:22+00:00

set_zone_contiguous() is only used in mm init/hotplug, and clear_zone_contiguous() only used in hotplug, move them from page_alloc.c to the more appropriate file. Link: https://lkml.kernel.org/r/20230516063821.121844-4-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Cc: David Hildenbrand Cc: "Huang, Ying" Cc: Iurii Zaikin Cc: Kees Cook Cc: Len Brown Cc: Luis Chamberlain Cc: Mike Rapoport (IBM) Cc: Oscar Salvador Cc: Pavel Machek Cc: Rafael J. Wysocki Signed-off-by: Andrew Morton