126 lines
2.8 KiB
C
126 lines
2.8 KiB
C
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/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __LINUX_PAGE_EXT_H
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#define __LINUX_PAGE_EXT_H
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#include <linux/types.h>
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#include <linux/stacktrace.h>
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#include <linux/stackdepot.h>
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struct pglist_data;
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/**
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* struct page_ext_operations - per page_ext client operations
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* @offset: Offset to the client's data within page_ext. Offset is returned to
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* the client by page_ext_init.
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* @size: The size of the client data within page_ext.
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* @need: Function that returns true if client requires page_ext.
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* @init: (optional) Called to initialize client once page_exts are allocated.
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* @need_shared_flags: True when client is using shared page_ext->flags
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* field.
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*
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* Each Page Extension client must define page_ext_operations in
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* page_ext_ops array.
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*/
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struct page_ext_operations {
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size_t offset;
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size_t size;
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bool (*need)(void);
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void (*init)(void);
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bool need_shared_flags;
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};
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#ifdef CONFIG_PAGE_EXTENSION
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/*
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* The page_ext_flags users must set need_shared_flags to true.
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*/
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enum page_ext_flags {
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PAGE_EXT_OWNER,
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PAGE_EXT_OWNER_ALLOCATED,
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#if defined(CONFIG_PAGE_IDLE_FLAG) && !defined(CONFIG_64BIT)
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PAGE_EXT_YOUNG,
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PAGE_EXT_IDLE,
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#endif
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};
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/*
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* Page Extension can be considered as an extended mem_map.
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* A page_ext page is associated with every page descriptor. The
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* page_ext helps us add more information about the page.
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* All page_ext are allocated at boot or memory hotplug event,
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* then the page_ext for pfn always exists.
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*/
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struct page_ext {
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unsigned long flags;
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};
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extern bool early_page_ext;
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extern unsigned long page_ext_size;
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extern void pgdat_page_ext_init(struct pglist_data *pgdat);
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static inline bool early_page_ext_enabled(void)
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{
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return early_page_ext;
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}
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#ifdef CONFIG_SPARSEMEM
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static inline void page_ext_init_flatmem(void)
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{
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}
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extern void page_ext_init(void);
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static inline void page_ext_init_flatmem_late(void)
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{
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}
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#else
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extern void page_ext_init_flatmem(void);
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extern void page_ext_init_flatmem_late(void);
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static inline void page_ext_init(void)
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{
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}
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#endif
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extern struct page_ext *page_ext_get(struct page *page);
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extern void page_ext_put(struct page_ext *page_ext);
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static inline struct page_ext *page_ext_next(struct page_ext *curr)
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{
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void *next = curr;
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next += page_ext_size;
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return next;
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}
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#else /* !CONFIG_PAGE_EXTENSION */
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struct page_ext;
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static inline bool early_page_ext_enabled(void)
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{
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return false;
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}
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static inline void pgdat_page_ext_init(struct pglist_data *pgdat)
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{
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}
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static inline void page_ext_init(void)
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{
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}
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static inline void page_ext_init_flatmem_late(void)
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{
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}
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static inline void page_ext_init_flatmem(void)
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{
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}
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static inline struct page_ext *page_ext_get(struct page *page)
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{
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return NULL;
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}
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static inline void page_ext_put(struct page_ext *page_ext)
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{
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}
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#endif /* CONFIG_PAGE_EXTENSION */
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#endif /* __LINUX_PAGE_EXT_H */
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