From 300709fbefd19ff7293c7d0ded9b56e69216e634 Mon Sep 17 00:00:00 2001 From: Sumanth Korikkar Date: Fri, 10 Oct 2025 10:51:47 +0200 Subject: mm/memory_hotplug: Remove MEM_PREPARE_ONLINE/MEM_FINISH_OFFLINE notifiers 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 --- include/linux/memory.h | 9 --------- 1 file changed, 9 deletions(-) (limited to 'include/linux/memory.h') diff --git a/include/linux/memory.h b/include/linux/memory.h index 0c214256216f..ba1515160894 100644 --- a/include/linux/memory.h +++ b/include/linux/memory.h @@ -96,17 +96,8 @@ int set_memory_block_size_order(unsigned int order); #define MEM_GOING_ONLINE (1<<3) #define MEM_CANCEL_ONLINE (1<<4) #define MEM_CANCEL_OFFLINE (1<<5) -#define MEM_PREPARE_ONLINE (1<<6) -#define MEM_FINISH_OFFLINE (1<<7) struct memory_notify { - /* - * The altmap_start_pfn and altmap_nr_pages fields are designated for - * specifying the altmap range and are exclusively intended for use in - * MEM_PREPARE_ONLINE/MEM_FINISH_OFFLINE notifiers. - */ - unsigned long altmap_start_pfn; - unsigned long altmap_nr_pages; unsigned long start_pfn; unsigned long nr_pages; }; -- cgit v1.2.3 From 1a4f70f6851a1916c4f0e52731c7ecfe99bf36e6 Mon Sep 17 00:00:00 2001 From: Israel Batista Date: Wed, 29 Oct 2025 19:56:28 +0000 Subject: mm: convert memory block states (MEM_*) macros to enum Patch series "mm: Convert memory block states (MEM_*) macros to enums", v2. The MEM_* constants indicating the state of a memory block are currently defined as macros, meaning their definitions will be omitted from the debuginfo on most kernel builds. This makes it harder for debuggers to correctly map the block state at runtime, which can be quite useful when analysing errors related to memory hot plugging and unplugging with tools such as drgn. Converting the constants to an enum ensures the correct information is emitted by the compiler and available for the debugger, without needing to hard-code them into the debugger and track their changes. This patch series aims to replace the current macros with a newly created enum named memory_block_state, while also taking advantage of the compile time guarantees that we get when using enums. The first patch does the conversion of the macros to an enum, while the 2nd and 3rd patches use this enum to clean up some type declarations and make sure that only valid values are used. This patch (of 3): Converting the MEM_* constants from macros to an enum ensures that their values will be correctly emitted in the debug symbols, making it easier to trace the meaning of each value when debugging with tools such as drgn, without the need to hard-code the values. Since the values are mutually exclusive and they are not exposed directly to userspace, I also dropped the misleading pattern (1< Acked-by: David Hildenbrand Acked-by: Mike Rapoport (Microsoft) Reviewed-by: Lorenzo Stoakes Cc: Omar Sandoval Cc: Randy Dunlap Signed-off-by: Andrew Morton --- include/linux/memory.h | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-) (limited to 'include/linux/memory.h') diff --git a/include/linux/memory.h b/include/linux/memory.h index 0c214256216f..f4e358477c6a 100644 --- a/include/linux/memory.h +++ b/include/linux/memory.h @@ -64,6 +64,18 @@ struct memory_group { }; }; +enum memory_block_state { + /* These states are exposed to userspace as text strings in sysfs */ + MEM_ONLINE, /* exposed to userspace */ + MEM_GOING_OFFLINE, /* exposed to userspace */ + MEM_OFFLINE, /* exposed to userspace */ + MEM_GOING_ONLINE, + MEM_CANCEL_ONLINE, + MEM_CANCEL_OFFLINE, + MEM_PREPARE_ONLINE, + MEM_FINISH_OFFLINE, +}; + struct memory_block { unsigned long start_section_nr; unsigned long state; /* serialized by the dev->lock */ @@ -89,16 +101,6 @@ int arch_get_memory_phys_device(unsigned long start_pfn); unsigned long memory_block_size_bytes(void); int set_memory_block_size_order(unsigned int order); -/* These states are exposed to userspace as text strings in sysfs */ -#define MEM_ONLINE (1<<0) /* exposed to userspace */ -#define MEM_GOING_OFFLINE (1<<1) /* exposed to userspace */ -#define MEM_OFFLINE (1<<2) /* exposed to userspace */ -#define MEM_GOING_ONLINE (1<<3) -#define MEM_CANCEL_ONLINE (1<<4) -#define MEM_CANCEL_OFFLINE (1<<5) -#define MEM_PREPARE_ONLINE (1<<6) -#define MEM_FINISH_OFFLINE (1<<7) - struct memory_notify { /* * The altmap_start_pfn and altmap_nr_pages fields are designated for -- cgit v1.2.3 From 8bc7ba3d265d6ee698de4b1941b7e8f7d91a0562 Mon Sep 17 00:00:00 2001 From: Israel Batista Date: Wed, 29 Oct 2025 19:56:30 +0000 Subject: mm: change type of state in struct memory_block The state of a memory block should be restricted to values specified in the documentation of the memory hotplug API. However, since the state field in the memory_block struct was defined as an unsigned long, this restriction was not enforced at compile time. With the introduction of the enum memory_block_state, it is now possible to incorporate the desired semantics in the field declaration and enforce these restrictions at compile time. [akpm@linux-foundation.org: fix whitespace, per Randy] Link: https://lkml.kernel.org/r/20251029195617.2210700-3-linux@israelbatista.dev.br Signed-off-by: Israel Batista Acked-by: David Hildenbrand Acked-by: Mike Rapoport (Microsoft) Reviewed-by: Lorenzo Stoakes Cc: Omar Sandoval Cc: Randy Dunlap Signed-off-by: Andrew Morton --- include/linux/memory.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/memory.h') diff --git a/include/linux/memory.h b/include/linux/memory.h index f4e358477c6a..ca20cbdd71f2 100644 --- a/include/linux/memory.h +++ b/include/linux/memory.h @@ -78,7 +78,7 @@ enum memory_block_state { struct memory_block { unsigned long start_section_nr; - unsigned long state; /* serialized by the dev->lock */ + enum memory_block_state state; /* serialized by the dev->lock */ int online_type; /* for passing data to online routine */ int nid; /* NID for this memory block */ /* -- cgit v1.2.3 From ed1f8855dd7b82a0ad87960b1729a3e848dc5589 Mon Sep 17 00:00:00 2001 From: Israel Batista Date: Wed, 29 Oct 2025 19:56:32 +0000 Subject: mm: change type of parameter for memory_notify memory_notify() is responsible for sending events related to memory hotplugging to a notification queue. Since all the events must match one of the values from the enum memory_block_state, it is appropriate to change the function parameter type to make this condition explicit at compile time. Link: https://lkml.kernel.org/r/20251029195617.2210700-4-linux@israelbatista.dev.br Signed-off-by: Israel Batista Acked-by: Mike Rapoport (Microsoft) Cc: David Hildenbrand Cc: Lorenzo Stoakes Cc: Omar Sandoval Cc: Randy Dunlap Signed-off-by: Andrew Morton --- include/linux/memory.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include/linux/memory.h') diff --git a/include/linux/memory.h b/include/linux/memory.h index ca20cbdd71f2..ca3eb1db6cc8 100644 --- a/include/linux/memory.h +++ b/include/linux/memory.h @@ -141,7 +141,7 @@ static inline int register_memory_notifier(struct notifier_block *nb) static inline void unregister_memory_notifier(struct notifier_block *nb) { } -static inline int memory_notify(unsigned long val, void *v) +static inline int memory_notify(enum memory_block_state state, void *v) { return 0; } @@ -165,7 +165,7 @@ int create_memory_block_devices(unsigned long start, unsigned long size, struct memory_group *group); void remove_memory_block_devices(unsigned long start, unsigned long size); extern void memory_dev_init(void); -extern int memory_notify(unsigned long val, void *v); +extern int memory_notify(enum memory_block_state state, void *v); extern struct memory_block *find_memory_block(unsigned long section_nr); typedef int (*walk_memory_blocks_func_t)(struct memory_block *, void *); extern int walk_memory_blocks(unsigned long start, unsigned long size, -- cgit v1.2.3