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torvalds-linux/include/linux/memory_hotplug.h
Sumanth Korikkar 300709fbef 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 <david@redhat.com>
Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2025-10-14 14:24:53 +02:00

322 lines
10 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __LINUX_MEMORY_HOTPLUG_H
#define __LINUX_MEMORY_HOTPLUG_H
#include <linux/mmzone.h>
#include <linux/spinlock.h>
#include <linux/notifier.h>
#include <linux/bug.h>
struct page;
struct zone;
struct pglist_data;
struct mem_section;
struct memory_group;
struct resource;
struct vmem_altmap;
struct dev_pagemap;
#ifdef CONFIG_MEMORY_HOTPLUG
struct page *pfn_to_online_page(unsigned long pfn);
/* Types for control the zone type of onlined and offlined memory */
enum {
/* Offline the memory. */
MMOP_OFFLINE = 0,
/* Online the memory. Zone depends, see default_zone_for_pfn(). */
MMOP_ONLINE,
/* Online the memory to ZONE_NORMAL. */
MMOP_ONLINE_KERNEL,
/* Online the memory to ZONE_MOVABLE. */
MMOP_ONLINE_MOVABLE,
};
/* Flags for add_memory() and friends to specify memory hotplug details. */
typedef int __bitwise mhp_t;
/* No special request */
#define MHP_NONE ((__force mhp_t)0)
/*
* Allow merging of the added System RAM resource with adjacent,
* mergeable resources. After a successful call to add_memory_resource()
* with this flag set, the resource pointer must no longer be used as it
* might be stale, or the resource might have changed.
*/
#define MHP_MERGE_RESOURCE ((__force mhp_t)BIT(0))
/*
* We want memmap (struct page array) to be self contained.
* To do so, we will use the beginning of the hot-added range to build
* the page tables for the memmap array that describes the entire range.
* Only selected architectures support it with SPARSE_VMEMMAP.
* This is only a hint, the core kernel can decide to not do this based on
* different alignment checks.
*/
#define MHP_MEMMAP_ON_MEMORY ((__force mhp_t)BIT(1))
/*
* The nid field specifies a memory group id (mgid) instead. The memory group
* implies the node id (nid).
*/
#define MHP_NID_IS_MGID ((__force mhp_t)BIT(2))
/*
* Extended parameters for memory hotplug:
* altmap: alternative allocator for memmap array (optional)
* pgprot: page protection flags to apply to newly created page tables
* (required)
*/
struct mhp_params {
struct vmem_altmap *altmap;
pgprot_t pgprot;
struct dev_pagemap *pgmap;
};
bool mhp_range_allowed(u64 start, u64 size, bool need_mapping);
struct range mhp_get_pluggable_range(bool need_mapping);
bool mhp_supports_memmap_on_memory(void);
/*
* Zone resizing functions
*
* Note: any attempt to resize a zone should has pgdat_resize_lock()
* zone_span_writelock() both held. This ensure the size of a zone
* can't be changed while pgdat_resize_lock() held.
*/
static inline unsigned zone_span_seqbegin(struct zone *zone)
{
return read_seqbegin(&zone->span_seqlock);
}
static inline int zone_span_seqretry(struct zone *zone, unsigned iv)
{
return read_seqretry(&zone->span_seqlock, iv);
}
static inline void zone_span_writelock(struct zone *zone)
{
write_seqlock(&zone->span_seqlock);
}
static inline void zone_span_writeunlock(struct zone *zone)
{
write_sequnlock(&zone->span_seqlock);
}
static inline void zone_seqlock_init(struct zone *zone)
{
seqlock_init(&zone->span_seqlock);
}
extern void adjust_present_page_count(struct page *page,
struct memory_group *group,
long nr_pages);
/* VM interface that may be used by firmware interface */
extern int mhp_init_memmap_on_memory(unsigned long pfn, unsigned long nr_pages,
struct zone *zone);
extern void mhp_deinit_memmap_on_memory(unsigned long pfn, unsigned long nr_pages);
extern int online_pages(unsigned long pfn, unsigned long nr_pages,
struct zone *zone, struct memory_group *group);
extern unsigned long __offline_isolated_pages(unsigned long start_pfn,
unsigned long end_pfn);
typedef void (*online_page_callback_t)(struct page *page, unsigned int order);
extern void generic_online_page(struct page *page, unsigned int order);
extern int set_online_page_callback(online_page_callback_t callback);
extern int restore_online_page_callback(online_page_callback_t callback);
extern int try_online_node(int nid);
extern int arch_add_memory(int nid, u64 start, u64 size,
struct mhp_params *params);
extern u64 max_mem_size;
extern int mhp_online_type_from_str(const char *str);
/* If movable_node boot option specified */
extern bool movable_node_enabled;
static inline bool movable_node_is_enabled(void)
{
return movable_node_enabled;
}
extern void arch_remove_memory(u64 start, u64 size, struct vmem_altmap *altmap);
extern void __remove_pages(unsigned long start_pfn, unsigned long nr_pages,
struct vmem_altmap *altmap);
/* reasonably generic interface to expand the physical pages */
extern int __add_pages(int nid, unsigned long start_pfn, unsigned long nr_pages,
struct mhp_params *params);
#ifndef CONFIG_ARCH_HAS_ADD_PAGES
static inline int add_pages(int nid, unsigned long start_pfn,
unsigned long nr_pages, struct mhp_params *params)
{
return __add_pages(nid, start_pfn, nr_pages, params);
}
#else /* ARCH_HAS_ADD_PAGES */
int add_pages(int nid, unsigned long start_pfn, unsigned long nr_pages,
struct mhp_params *params);
#endif /* ARCH_HAS_ADD_PAGES */
void get_online_mems(void);
void put_online_mems(void);
void mem_hotplug_begin(void);
void mem_hotplug_done(void);
/* See kswapd_is_running() */
static inline void pgdat_kswapd_lock(pg_data_t *pgdat)
{
mutex_lock(&pgdat->kswapd_lock);
}
static inline void pgdat_kswapd_unlock(pg_data_t *pgdat)
{
mutex_unlock(&pgdat->kswapd_lock);
}
static inline void pgdat_kswapd_lock_init(pg_data_t *pgdat)
{
mutex_init(&pgdat->kswapd_lock);
}
#else /* ! CONFIG_MEMORY_HOTPLUG */
#define pfn_to_online_page(pfn) \
({ \
struct page *___page = NULL; \
if (pfn_valid(pfn)) \
___page = pfn_to_page(pfn); \
___page; \
})
static inline unsigned zone_span_seqbegin(struct zone *zone)
{
return 0;
}
static inline int zone_span_seqretry(struct zone *zone, unsigned iv)
{
return 0;
}
static inline void zone_span_writelock(struct zone *zone) {}
static inline void zone_span_writeunlock(struct zone *zone) {}
static inline void zone_seqlock_init(struct zone *zone) {}
static inline int try_online_node(int nid)
{
return 0;
}
static inline void get_online_mems(void) {}
static inline void put_online_mems(void) {}
static inline void mem_hotplug_begin(void) {}
static inline void mem_hotplug_done(void) {}
static inline bool movable_node_is_enabled(void)
{
return false;
}
static inline bool mhp_supports_memmap_on_memory(void)
{
return false;
}
static inline void pgdat_kswapd_lock(pg_data_t *pgdat) {}
static inline void pgdat_kswapd_unlock(pg_data_t *pgdat) {}
static inline void pgdat_kswapd_lock_init(pg_data_t *pgdat) {}
#endif /* ! CONFIG_MEMORY_HOTPLUG */
/*
* Keep this declaration outside CONFIG_MEMORY_HOTPLUG as some
* platforms might override and use arch_get_mappable_range()
* for internal non memory hotplug purposes.
*/
struct range arch_get_mappable_range(void);
#if defined(CONFIG_MEMORY_HOTPLUG) || defined(CONFIG_DEFERRED_STRUCT_PAGE_INIT)
/*
* pgdat resizing functions
*/
static inline
void pgdat_resize_lock(struct pglist_data *pgdat, unsigned long *flags)
{
spin_lock_irqsave(&pgdat->node_size_lock, *flags);
}
static inline
void pgdat_resize_unlock(struct pglist_data *pgdat, unsigned long *flags)
{
spin_unlock_irqrestore(&pgdat->node_size_lock, *flags);
}
static inline
void pgdat_resize_init(struct pglist_data *pgdat)
{
spin_lock_init(&pgdat->node_size_lock);
}
#else /* !(CONFIG_MEMORY_HOTPLUG || CONFIG_DEFERRED_STRUCT_PAGE_INIT) */
/*
* Stub functions for when hotplug is off
*/
static inline void pgdat_resize_lock(struct pglist_data *p, unsigned long *f) {}
static inline void pgdat_resize_unlock(struct pglist_data *p, unsigned long *f) {}
static inline void pgdat_resize_init(struct pglist_data *pgdat) {}
#endif /* !(CONFIG_MEMORY_HOTPLUG || CONFIG_DEFERRED_STRUCT_PAGE_INIT) */
#ifdef CONFIG_MEMORY_HOTREMOVE
extern void try_offline_node(int nid);
extern int offline_pages(unsigned long start_pfn, unsigned long nr_pages,
struct zone *zone, struct memory_group *group);
extern int remove_memory(u64 start, u64 size);
extern void __remove_memory(u64 start, u64 size);
extern int offline_and_remove_memory(u64 start, u64 size);
#else
static inline void try_offline_node(int nid) {}
static inline int offline_pages(unsigned long start_pfn, unsigned long nr_pages,
struct zone *zone, struct memory_group *group)
{
return -EINVAL;
}
static inline int remove_memory(u64 start, u64 size)
{
return -EBUSY;
}
static inline void __remove_memory(u64 start, u64 size) {}
#endif /* CONFIG_MEMORY_HOTREMOVE */
#ifdef CONFIG_MEMORY_HOTPLUG
/* Default online_type (MMOP_*) when new memory blocks are added. */
extern int mhp_get_default_online_type(void);
extern void mhp_set_default_online_type(int online_type);
extern void __ref free_area_init_core_hotplug(struct pglist_data *pgdat);
extern int __add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags);
extern int add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags);
extern int add_memory_resource(int nid, struct resource *resource,
mhp_t mhp_flags);
extern int add_memory_driver_managed(int nid, u64 start, u64 size,
const char *resource_name,
mhp_t mhp_flags);
extern void move_pfn_range_to_zone(struct zone *zone, unsigned long start_pfn,
unsigned long nr_pages,
struct vmem_altmap *altmap, int migratetype,
bool isolate_pageblock);
extern void remove_pfn_range_from_zone(struct zone *zone,
unsigned long start_pfn,
unsigned long nr_pages);
extern int sparse_add_section(int nid, unsigned long pfn,
unsigned long nr_pages, struct vmem_altmap *altmap,
struct dev_pagemap *pgmap);
extern void sparse_remove_section(unsigned long pfn, unsigned long nr_pages,
struct vmem_altmap *altmap);
extern struct page *sparse_decode_mem_map(unsigned long coded_mem_map,
unsigned long pnum);
extern struct zone *zone_for_pfn_range(int online_type, int nid,
struct memory_group *group, unsigned long start_pfn,
unsigned long nr_pages);
extern int arch_create_linear_mapping(int nid, u64 start, u64 size,
struct mhp_params *params);
void arch_remove_linear_mapping(u64 start, u64 size);
#endif /* CONFIG_MEMORY_HOTPLUG */
#endif /* __LINUX_MEMORY_HOTPLUG_H */