forked from mirrors/linux
6e65aa55cd
In order to constify other functions, we need page_ext_get() to be const. This is no problem as lookup_page_ext() already takes a const argument. Link: https://lkml.kernel.org/r/20240326171045.410737-4-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
129 lines
2.9 KiB
C
129 lines
2.9 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
#ifndef __LINUX_PAGE_EXT_H
|
|
#define __LINUX_PAGE_EXT_H
|
|
|
|
#include <linux/types.h>
|
|
#include <linux/stacktrace.h>
|
|
|
|
struct pglist_data;
|
|
|
|
#ifdef CONFIG_PAGE_EXTENSION
|
|
/**
|
|
* struct page_ext_operations - per page_ext client operations
|
|
* @offset: Offset to the client's data within page_ext. Offset is returned to
|
|
* the client by page_ext_init.
|
|
* @size: The size of the client data within page_ext.
|
|
* @need: Function that returns true if client requires page_ext.
|
|
* @init: (optional) Called to initialize client once page_exts are allocated.
|
|
* @need_shared_flags: True when client is using shared page_ext->flags
|
|
* field.
|
|
*
|
|
* Each Page Extension client must define page_ext_operations in
|
|
* page_ext_ops array.
|
|
*/
|
|
struct page_ext_operations {
|
|
size_t offset;
|
|
size_t size;
|
|
bool (*need)(void);
|
|
void (*init)(void);
|
|
bool need_shared_flags;
|
|
};
|
|
|
|
/*
|
|
* The page_ext_flags users must set need_shared_flags to true.
|
|
*/
|
|
enum page_ext_flags {
|
|
PAGE_EXT_OWNER,
|
|
PAGE_EXT_OWNER_ALLOCATED,
|
|
#if defined(CONFIG_PAGE_IDLE_FLAG) && !defined(CONFIG_64BIT)
|
|
PAGE_EXT_YOUNG,
|
|
PAGE_EXT_IDLE,
|
|
#endif
|
|
};
|
|
|
|
/*
|
|
* Page Extension can be considered as an extended mem_map.
|
|
* A page_ext page is associated with every page descriptor. The
|
|
* page_ext helps us add more information about the page.
|
|
* All page_ext are allocated at boot or memory hotplug event,
|
|
* then the page_ext for pfn always exists.
|
|
*/
|
|
struct page_ext {
|
|
unsigned long flags;
|
|
};
|
|
|
|
extern bool early_page_ext;
|
|
extern unsigned long page_ext_size;
|
|
extern void pgdat_page_ext_init(struct pglist_data *pgdat);
|
|
|
|
static inline bool early_page_ext_enabled(void)
|
|
{
|
|
return early_page_ext;
|
|
}
|
|
|
|
#ifdef CONFIG_SPARSEMEM
|
|
static inline void page_ext_init_flatmem(void)
|
|
{
|
|
}
|
|
extern void page_ext_init(void);
|
|
static inline void page_ext_init_flatmem_late(void)
|
|
{
|
|
}
|
|
#else
|
|
extern void page_ext_init_flatmem(void);
|
|
extern void page_ext_init_flatmem_late(void);
|
|
static inline void page_ext_init(void)
|
|
{
|
|
}
|
|
#endif
|
|
|
|
extern struct page_ext *page_ext_get(const struct page *page);
|
|
extern void page_ext_put(struct page_ext *page_ext);
|
|
|
|
static inline void *page_ext_data(struct page_ext *page_ext,
|
|
struct page_ext_operations *ops)
|
|
{
|
|
return (void *)(page_ext) + ops->offset;
|
|
}
|
|
|
|
static inline struct page_ext *page_ext_next(struct page_ext *curr)
|
|
{
|
|
void *next = curr;
|
|
next += page_ext_size;
|
|
return next;
|
|
}
|
|
|
|
#else /* !CONFIG_PAGE_EXTENSION */
|
|
struct page_ext;
|
|
|
|
static inline bool early_page_ext_enabled(void)
|
|
{
|
|
return false;
|
|
}
|
|
|
|
static inline void pgdat_page_ext_init(struct pglist_data *pgdat)
|
|
{
|
|
}
|
|
|
|
static inline void page_ext_init(void)
|
|
{
|
|
}
|
|
|
|
static inline void page_ext_init_flatmem_late(void)
|
|
{
|
|
}
|
|
|
|
static inline void page_ext_init_flatmem(void)
|
|
{
|
|
}
|
|
|
|
static inline struct page_ext *page_ext_get(const struct page *page)
|
|
{
|
|
return NULL;
|
|
}
|
|
|
|
static inline void page_ext_put(struct page_ext *page_ext)
|
|
{
|
|
}
|
|
#endif /* CONFIG_PAGE_EXTENSION */
|
|
#endif /* __LINUX_PAGE_EXT_H */
|