Line data    Source code

       1             : /* SPDX-License-Identifier: GPL-2.0 */
       2             : #ifndef __LINUX_PAGE_EXT_H
       3             : #define __LINUX_PAGE_EXT_H
       4             : 
       5             : #include <linux/types.h>
       6             : #include <linux/stacktrace.h>
       7             : #include <linux/stackdepot.h>
       8             : 
       9             : struct pglist_data;
      10             : struct page_ext_operations {
      11             :         size_t offset;
      12             :         size_t size;
      13             :         bool (*need)(void);
      14             :         void (*init)(void);
      15             : };
      16             : 
      17             : #ifdef CONFIG_PAGE_EXTENSION
      18             : 
      19             : enum page_ext_flags {
      20             :         PAGE_EXT_OWNER,
      21             :         PAGE_EXT_OWNER_ALLOCATED,
      22             : #if defined(CONFIG_IDLE_PAGE_TRACKING) && !defined(CONFIG_64BIT)
      23             :         PAGE_EXT_YOUNG,
      24             :         PAGE_EXT_IDLE,
      25             : #endif
      26             : };
      27             : 
      28             : /*
      29             :  * Page Extension can be considered as an extended mem_map.
      30             :  * A page_ext page is associated with every page descriptor. The
      31             :  * page_ext helps us add more information about the page.
      32             :  * All page_ext are allocated at boot or memory hotplug event,
      33             :  * then the page_ext for pfn always exists.
      34             :  */
      35             : struct page_ext {
      36             :         unsigned long flags;
      37             : };
      38             : 
      39             : extern unsigned long page_ext_size;
      40             : extern void pgdat_page_ext_init(struct pglist_data *pgdat);
      41             : 
      42             : #ifdef CONFIG_SPARSEMEM
      43             : static inline void page_ext_init_flatmem(void)
      44             : {
      45             : }
      46             : extern void page_ext_init(void);
      47             : static inline void page_ext_init_flatmem_late(void)
      48             : {
      49             : }
      50             : #else
      51             : extern void page_ext_init_flatmem(void);
      52             : extern void page_ext_init_flatmem_late(void);
      53             : static inline void page_ext_init(void)
      54             : {
      55             : }
      56             : #endif
      57             : 
      58             : struct page_ext *lookup_page_ext(const struct page *page);
      59             : 
      60             : static inline struct page_ext *page_ext_next(struct page_ext *curr)
      61             : {
      62             :         void *next = curr;
      63             :         next += page_ext_size;
      64             :         return next;
      65             : }
      66             : 
      67             : #else /* !CONFIG_PAGE_EXTENSION */
      68             : struct page_ext;
      69             : 
      70           1 : static inline void pgdat_page_ext_init(struct pglist_data *pgdat)
      71             : {
      72           1 : }
      73             : 
      74             : static inline struct page_ext *lookup_page_ext(const struct page *page)
      75             : {
      76             :         return NULL;
      77             : }
      78             : 
      79           1 : static inline void page_ext_init(void)
      80             : {
      81           1 : }
      82             : 
      83           1 : static inline void page_ext_init_flatmem_late(void)
      84             : {
      85           1 : }
      86             : 
      87           1 : static inline void page_ext_init_flatmem(void)
      88             : {
      89           1 : }
      90             : #endif /* CONFIG_PAGE_EXTENSION */
      91             : #endif /* __LINUX_PAGE_EXT_H */