/* SPDX-License-Identifier: GPL-2.0-or-later *//* * mm-internal API for the page (buddy) allocator. Public API lives in * include/linux/gfp.h. */#ifndef __MM_PAGE_ALLOC_H#define __MM_PAGE_ALLOC_H #include <linux/mm.h>#include <linux/mmzone.h>#include <linux/nodemask.h>#include <linux/types.h> #define ALLOC_DEFAULT 0/* The ALLOC_WMARK bits are used as an index to zone->watermark */#define ALLOC_WMARK_MIN WMARK_MIN#define ALLOC_WMARK_LOW WMARK_LOW#define ALLOC_WMARK_HIGH WMARK_HIGH#define ALLOC_NO_WATERMARKS 0x04 /* don't check watermarks at all */ /* Mask to get the watermark bits */#define ALLOC_WMARK_MASK (ALLOC_NO_WATERMARKS-1) /* * Only MMU archs have async oom victim reclaim - aka oom_reaper so we * cannot assume a reduced access to memory reserves is sufficient for * !MMU */#ifdef CONFIG_MMU#define ALLOC_OOM 0x08#else#define ALLOC_OOM ALLOC_NO_WATERMARKS#endif #define ALLOC_NON_BLOCK 0x10 /* Caller cannot block. Allow access * to 25% of the min watermark or * 62.5% if __GFP_HIGH is set. */#define ALLOC_MIN_RESERVE 0x20 /* __GFP_HIGH set. Allow access to 50% * of the min watermark. */#define ALLOC_CPUSET 0x40 /* check for correct cpuset */#define ALLOC_CMA 0x80 /* allow allocations from CMA areas */#ifdef CONFIG_ZONE_DMA32#define ALLOC_NOFRAGMENT 0x100 /* avoid mixing pageblock types */#else#define ALLOC_NOFRAGMENT 0x0#endif#define ALLOC_HIGHATOMIC 0x200 /* Allows access to MIGRATE_HIGHATOMIC */#define ALLOC_NOLOCK 0x400 /* Only use spin_trylock in allocation path */#define ALLOC_KSWAPD 0x800 /* allow waking of kswapd, __GFP_KSWAPD_RECLAIM set *//* * Avoid alloc_tag recursion for internal allocations. * * Callers must clear_page_tag_ref() before freeing to avoid warnings from * alloc_tag_sub_check(). */#define ALLOC_NO_CODETAG 0x1000 /* Flags that allow allocations below the min watermark. */#define ALLOC_RESERVES (ALLOC_NON_BLOCK|ALLOC_MIN_RESERVE|ALLOC_HIGHATOMIC|ALLOC_OOM) /* * Structure for holding the mostly immutable allocation parameters passed * between functions involved in allocations, including the alloc_pages* * family of functions. * * nodemask, migratetype and highest_zoneidx are initialized only once in * __alloc_pages() and then never change. * * zonelist, preferred_zone and highest_zoneidx are set first in * __alloc_pages() for the fast path, and might be later changed * in __alloc_pages_slowpath(). All other functions pass the whole structure * by a const pointer. */struct alloc_context { struct zonelist *zonelist; const nodemask_t *nodemask; struct zoneref *preferred_zoneref; int migratetype; /* * highest_zoneidx represents highest usable zone index of * the allocation request. Due to the nature of the zone, * memory on lower zone than the highest_zoneidx will be * protected by lowmem_reserve[highest_zoneidx]. * * highest_zoneidx is also used by reclaim/compaction to limit * the target zone since higher zone than this index cannot be * usable for this allocation request. */ enum zone_type highest_zoneidx; bool spread_dirty_pages; /* Only flags that are global to the whole allocation go here. */ unsigned int alloc_flags;}; /* * This function returns the order of a free page in the buddy system. In * general, page_zone(page)->lock must be held by the caller to prevent the * page from being allocated in parallel and returning garbage as the order. * If a caller does not hold page_zone(page)->lock, it must guarantee that the * page cannot be allocated or merged in parallel. Alternatively, it must * handle invalid values gracefully, and use buddy_order_unsafe() below. */static inline unsigned int buddy_order(struct page *page){ /* PageBuddy() must be checked by the caller */ return page_private(page);} /* * Like buddy_order(), but for callers who cannot afford to hold the zone lock. * PageBuddy() should be checked first by the caller to minimize race window, * and invalid values must be handled gracefully. * * READ_ONCE is used so that if the caller assigns the result into a local * variable and e.g. tests it for valid range before using, the compiler cannot * decide to remove the variable and inline the page_private(page) multiple * times, potentially observing different values in the tests and the actual * use of the result. */#define buddy_order_unsafe(page) READ_ONCE(page_private(page)) /* * This function checks whether a page is free && is the buddy * we can coalesce a page and its buddy if * (a) the buddy is not in a hole (check before calling!) && * (b) the buddy is in the buddy system && * (c) a page and its buddy have the same order && * (d) a page and its buddy are in the same zone. * * For recording whether a page is in the buddy system, we set PageBuddy. * Setting, clearing, and testing PageBuddy is serialized by zone->lock. * * For recording page's order, we use page_private(page). */static inline bool page_is_buddy(struct page *page, struct page *buddy, unsigned int order){ if (!page_is_guard(buddy) && !PageBuddy(buddy)) return false; if (buddy_order(buddy) != order) return false; /* * zone check is done late to avoid uselessly calculating * zone/node ids for pages that could never merge. */ if (page_zone_id(page) != page_zone_id(buddy)) return false; VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy); return true;} /* * Locate the struct page for both the matching buddy in our * pair (buddy1) and the combined O(n+1) page they form (page). * * 1) Any buddy B1 will have an order O twin B2 which satisfies * the following equation: * B2 = B1 ^ (1 << O) * For example, if the starting buddy (buddy2) is #8 its order * 1 buddy is #10: * B2 = 8 ^ (1 << 1) = 8 ^ 2 = 10 * * 2) Any buddy B will have an order O+1 parent P which * satisfies the following equation: * P = B & ~(1 << O) * * Assumption: *_mem_map is contiguous at least up to MAX_PAGE_ORDER */static inline unsigned long__find_buddy_pfn(unsigned long page_pfn, unsigned int order){ return page_pfn ^ (1 << order);} /* * Find the buddy of @page and validate it. * @page: The input page * @pfn: The pfn of the page, it saves a call to page_to_pfn() when the * function is used in the performance-critical __free_one_page(). * @order: The order of the page * @buddy_pfn: The output pointer to the buddy pfn, it also saves a call to * page_to_pfn(). * * The found buddy can be a non PageBuddy, out of @page's zone, or its order is * not the same as @page. The validation is necessary before use it. * * Return: the found buddy page or NULL if not found. */static inline struct page *find_buddy_page_pfn(struct page *page, unsigned long pfn, unsigned int order, unsigned long *buddy_pfn){ unsigned long __buddy_pfn = __find_buddy_pfn(pfn, order); struct page *buddy; buddy = page + (__buddy_pfn - pfn); if (buddy_pfn) *buddy_pfn = __buddy_pfn; if (page_is_buddy(page, buddy, order)) return buddy; return NULL;} extern struct page *__pageblock_pfn_to_page(unsigned long start_pfn, unsigned long end_pfn, struct zone *zone); static inline struct page *pageblock_pfn_to_page(unsigned long start_pfn, unsigned long end_pfn, struct zone *zone){ if (zone->contiguous) return pfn_to_page(start_pfn); return __pageblock_pfn_to_page(start_pfn, end_pfn, zone);} extern void __free_pages_core(struct page *page, unsigned int order, enum meminit_context context); void post_alloc_hook(struct page *page, unsigned int order, gfp_t gfp_flags, unsigned int alloc_flags);extern bool free_pages_prepare(struct page *page, unsigned int order); extern int user_min_free_kbytes; struct page *__alloc_frozen_pages_noprof(gfp_t gfp, unsigned int order, int nid, nodemask_t *nodemask, unsigned int alloc_flags);#define __alloc_frozen_pages(...) \ alloc_hooks(__alloc_frozen_pages_noprof(__VA_ARGS__))void free_frozen_pages(struct page *page, unsigned int order);void free_unref_folios(struct folio_batch *fbatch); #ifdef CONFIG_NUMAstruct page *alloc_frozen_pages_noprof(gfp_t, unsigned int order);#elsestatic inline struct page *alloc_frozen_pages_noprof(gfp_t gfp, unsigned int order){ return __alloc_frozen_pages_noprof(gfp, order, numa_node_id(), NULL, ALLOC_DEFAULT);}#endif #define alloc_frozen_pages(...) \ alloc_hooks(alloc_frozen_pages_noprof(__VA_ARGS__)) struct page *alloc_frozen_pages_nolock_noprof(gfp_t gfp_flags, int nid, unsigned int order);#define alloc_frozen_pages_nolock(...) \ alloc_hooks(alloc_frozen_pages_nolock_noprof(__VA_ARGS__))void free_frozen_pages_nolock(struct page *page, unsigned int order); struct page *__alloc_pages_noprof(gfp_t gfp, unsigned int order, int preferred_nid, nodemask_t *nodemask, unsigned int alloc_flags);#define __alloc_pages(...) alloc_hooks(__alloc_pages_noprof(__VA_ARGS__)) extern void zone_pcp_reset(struct zone *zone);extern void zone_pcp_disable(struct zone *zone);extern void zone_pcp_enable(struct zone *zone);extern void zone_pcp_init(struct zone *zone); enum fallback_result { /* Found suitable migratetype, *mt_out is valid. */ FALLBACK_FOUND, /* No fallback found in requested order. */ FALLBACK_EMPTY, /* Passed @claimable, but claiming whole block is a bad idea. */ FALLBACK_NOCLAIM,};enum fallback_resultfind_suitable_fallback(struct free_area *area, unsigned int order, int migratetype, bool claimable, int *mt_out); static inline bool free_area_empty(struct free_area *area, int migratetype){ return list_empty(&area->free_list[migratetype]);} /* Convert GFP flags to their corresponding migrate type */#define GFP_MOVABLE_MASK (__GFP_RECLAIMABLE|__GFP_MOVABLE)#define GFP_MOVABLE_SHIFT 3 static inline int gfp_migratetype(const gfp_t gfp_flags){ VM_WARN_ON((gfp_flags & GFP_MOVABLE_MASK) == GFP_MOVABLE_MASK); BUILD_BUG_ON((1UL << GFP_MOVABLE_SHIFT) != ___GFP_MOVABLE); BUILD_BUG_ON((___GFP_MOVABLE >> GFP_MOVABLE_SHIFT) != MIGRATE_MOVABLE); BUILD_BUG_ON((___GFP_RECLAIMABLE >> GFP_MOVABLE_SHIFT) != MIGRATE_RECLAIMABLE); BUILD_BUG_ON(((___GFP_MOVABLE | ___GFP_RECLAIMABLE) >> GFP_MOVABLE_SHIFT) != MIGRATE_HIGHATOMIC); if (unlikely(page_group_by_mobility_disabled)) return MIGRATE_UNMOVABLE; /* Group based on mobility */ return (__force unsigned long)(gfp_flags & GFP_MOVABLE_MASK) >> GFP_MOVABLE_SHIFT;}#undef GFP_MOVABLE_MASK#undef GFP_MOVABLE_SHIFT bool decay_pcp_high(struct zone *zone, struct per_cpu_pages *pcp);void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp);void drain_all_pages(struct zone *zone); void page_alloc_init_cpuhp(void);void page_alloc_sysctl_init(void); #endif /* __MM_PAGE_ALLOC_H */
/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* mm-internal API for the page (buddy) allocator. Public API lives in
* include/linux/gfp.h.
*/
#ifndef __MM_PAGE_ALLOC_H
#define __MM_PAGE_ALLOC_H
#include <linux/mm.h>
#include <linux/mmzone.h>
#include <linux/nodemask.h>
#include <linux/types.h>
#define ALLOC_DEFAULT 0
/* The ALLOC_WMARK bits are used as an index to zone->watermark */
#define ALLOC_WMARK_MIN WMARK_MIN
#define ALLOC_WMARK_LOW WMARK_LOW
#define ALLOC_WMARK_HIGH WMARK_HIGH
#define ALLOC_NO_WATERMARKS 0x04 /* don't check watermarks at all */
/* Mask to get the watermark bits */
#define ALLOC_WMARK_MASK (ALLOC_NO_WATERMARKS-1)
/*
* Only MMU archs have async oom victim reclaim - aka oom_reaper so we
* cannot assume a reduced access to memory reserves is sufficient for
* !MMU
*/
#ifdef CONFIG_MMU
#define ALLOC_OOM 0x08
#else
#define ALLOC_OOM ALLOC_NO_WATERMARKS
#endif
#define ALLOC_NON_BLOCK 0x10 /* Caller cannot block. Allow access
* to 25% of the min watermark or
* 62.5% if __GFP_HIGH is set.
*/
#define ALLOC_MIN_RESERVE 0x20 /* __GFP_HIGH set. Allow access to 50%
* of the min watermark.
*/
#define ALLOC_CPUSET 0x40 /* check for correct cpuset */
#define ALLOC_CMA 0x80 /* allow allocations from CMA areas */
#ifdef CONFIG_ZONE_DMA32
#define ALLOC_NOFRAGMENT 0x100 /* avoid mixing pageblock types */
#else
#define ALLOC_NOFRAGMENT 0x0
#endif
#define ALLOC_HIGHATOMIC 0x200 /* Allows access to MIGRATE_HIGHATOMIC */
#define ALLOC_NOLOCK 0x400 /* Only use spin_trylock in allocation path */
#define ALLOC_KSWAPD 0x800 /* allow waking of kswapd, __GFP_KSWAPD_RECLAIM set */
/*
* Avoid alloc_tag recursion for internal allocations.
*
* Callers must clear_page_tag_ref() before freeing to avoid warnings from
* alloc_tag_sub_check().
*/
#define ALLOC_NO_CODETAG 0x1000
/* Flags that allow allocations below the min watermark. */
#define ALLOC_RESERVES (ALLOC_NON_BLOCK|ALLOC_MIN_RESERVE|ALLOC_HIGHATOMIC|ALLOC_OOM)
/*
* Structure for holding the mostly immutable allocation parameters passed
* between functions involved in allocations, including the alloc_pages*
* family of functions.
*
* nodemask, migratetype and highest_zoneidx are initialized only once in
* __alloc_pages() and then never change.
*
* zonelist, preferred_zone and highest_zoneidx are set first in
* __alloc_pages() for the fast path, and might be later changed
* in __alloc_pages_slowpath(). All other functions pass the whole structure
* by a const pointer.
*/
struct alloc_context {
struct zonelist *zonelist;
const nodemask_t *nodemask;
struct zoneref *preferred_zoneref;
int migratetype;
/*
* highest_zoneidx represents highest usable zone index of
* the allocation request. Due to the nature of the zone,
* memory on lower zone than the highest_zoneidx will be
* protected by lowmem_reserve[highest_zoneidx].
*
* highest_zoneidx is also used by reclaim/compaction to limit
* the target zone since higher zone than this index cannot be
* usable for this allocation request.
*/
enum zone_type highest_zoneidx;
bool spread_dirty_pages;
/* Only flags that are global to the whole allocation go here. */
unsigned int alloc_flags;
};
/*
* This function returns the order of a free page in the buddy system. In
* general, page_zone(page)->lock must be held by the caller to prevent the
* page from being allocated in parallel and returning garbage as the order.
* If a caller does not hold page_zone(page)->lock, it must guarantee that the
* page cannot be allocated or merged in parallel. Alternatively, it must
* handle invalid values gracefully, and use buddy_order_unsafe() below.
*/
static inline unsigned int buddy_order(struct page *page)
{
/* PageBuddy() must be checked by the caller */
return page_private(page);
}
/*
* Like buddy_order(), but for callers who cannot afford to hold the zone lock.
* PageBuddy() should be checked first by the caller to minimize race window,
* and invalid values must be handled gracefully.
*
* READ_ONCE is used so that if the caller assigns the result into a local
* variable and e.g. tests it for valid range before using, the compiler cannot
* decide to remove the variable and inline the page_private(page) multiple
* times, potentially observing different values in the tests and the actual
* use of the result.
*/
#define buddy_order_unsafe(page) READ_ONCE(page_private(page))
/*
* This function checks whether a page is free && is the buddy
* we can coalesce a page and its buddy if
* (a) the buddy is not in a hole (check before calling!) &&
* (b) the buddy is in the buddy system &&
* (c) a page and its buddy have the same order &&
* (d) a page and its buddy are in the same zone.
*
* For recording whether a page is in the buddy system, we set PageBuddy.
* Setting, clearing, and testing PageBuddy is serialized by zone->lock.
*
* For recording page's order, we use page_private(page).
*/
static inline bool page_is_buddy(struct page *page, struct page *buddy,
unsigned int order)
{
if (!page_is_guard(buddy) && !PageBuddy(buddy))
return false;
if (buddy_order(buddy) != order)
return false;
/*
* zone check is done late to avoid uselessly calculating
* zone/node ids for pages that could never merge.
*/
if (page_zone_id(page) != page_zone_id(buddy))
return false;
VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy);
return true;
}
/*
* Locate the struct page for both the matching buddy in our
* pair (buddy1) and the combined O(n+1) page they form (page).
*
* 1) Any buddy B1 will have an order O twin B2 which satisfies
* the following equation:
* B2 = B1 ^ (1 << O)
* For example, if the starting buddy (buddy2) is #8 its order
* 1 buddy is #10:
* B2 = 8 ^ (1 << 1) = 8 ^ 2 = 10
*
* 2) Any buddy B will have an order O+1 parent P which
* satisfies the following equation:
* P = B & ~(1 << O)
*
* Assumption: *_mem_map is contiguous at least up to MAX_PAGE_ORDER
*/
static inline unsigned long
__find_buddy_pfn(unsigned long page_pfn, unsigned int order)
{
return page_pfn ^ (1 << order);
}
/*
* Find the buddy of @page and validate it.
* @page: The input page
* @pfn: The pfn of the page, it saves a call to page_to_pfn() when the
* function is used in the performance-critical __free_one_page().
* @order: The order of the page
* @buddy_pfn: The output pointer to the buddy pfn, it also saves a call to
* page_to_pfn().
*
* The found buddy can be a non PageBuddy, out of @page's zone, or its order is
* not the same as @page. The validation is necessary before use it.
*
* Return: the found buddy page or NULL if not found.
*/
static inline struct page *find_buddy_page_pfn(struct page *page,
unsigned long pfn, unsigned int order, unsigned long *buddy_pfn)
{
unsigned long __buddy_pfn = __find_buddy_pfn(pfn, order);
struct page *buddy;
buddy = page + (__buddy_pfn - pfn);
if (buddy_pfn)
*buddy_pfn = __buddy_pfn;
if (page_is_buddy(page, buddy, order))
return buddy;
return NULL;
}
extern struct page *__pageblock_pfn_to_page(unsigned long start_pfn,
unsigned long end_pfn, struct zone *zone);
static inline struct page *pageblock_pfn_to_page(unsigned long start_pfn,
unsigned long end_pfn, struct zone *zone)
{
if (zone->contiguous)
return pfn_to_page(start_pfn);
return __pageblock_pfn_to_page(start_pfn, end_pfn, zone);
}
extern void __free_pages_core(struct page *page, unsigned int order,
enum meminit_context context);
void post_alloc_hook(struct page *page, unsigned int order, gfp_t gfp_flags,
unsigned int alloc_flags);
extern bool free_pages_prepare(struct page *page, unsigned int order);
extern int user_min_free_kbytes;
struct page *__alloc_frozen_pages_noprof(gfp_t gfp, unsigned int order, int nid,
nodemask_t *nodemask, unsigned int alloc_flags);
#define __alloc_frozen_pages(...) \
alloc_hooks(__alloc_frozen_pages_noprof(__VA_ARGS__))
void free_frozen_pages(struct page *page, unsigned int order);
void free_unref_folios(struct folio_batch *fbatch);
#ifdef CONFIG_NUMA
struct page *alloc_frozen_pages_noprof(gfp_t, unsigned int order);
#else
static inline struct page *alloc_frozen_pages_noprof(gfp_t gfp, unsigned int order)
{
return __alloc_frozen_pages_noprof(gfp, order, numa_node_id(), NULL,
ALLOC_DEFAULT);
}
#endif
#define alloc_frozen_pages(...) \
alloc_hooks(alloc_frozen_pages_noprof(__VA_ARGS__))
struct page *alloc_frozen_pages_nolock_noprof(gfp_t gfp_flags, int nid, unsigned int order);
#define alloc_frozen_pages_nolock(...) \
alloc_hooks(alloc_frozen_pages_nolock_noprof(__VA_ARGS__))
void free_frozen_pages_nolock(struct page *page, unsigned int order);
struct page *__alloc_pages_noprof(gfp_t gfp, unsigned int order, int preferred_nid,
nodemask_t *nodemask, unsigned int alloc_flags);
#define __alloc_pages(...) alloc_hooks(__alloc_pages_noprof(__VA_ARGS__))
extern void zone_pcp_reset(struct zone *zone);
extern void zone_pcp_disable(struct zone *zone);
extern void zone_pcp_enable(struct zone *zone);
extern void zone_pcp_init(struct zone *zone);
enum fallback_result {
/* Found suitable migratetype, *mt_out is valid. */
FALLBACK_FOUND,
/* No fallback found in requested order. */
FALLBACK_EMPTY,
/* Passed @claimable, but claiming whole block is a bad idea. */
FALLBACK_NOCLAIM,
};
enum fallback_result
find_suitable_fallback(struct free_area *area, unsigned int order,
int migratetype, bool claimable, int *mt_out);
static inline bool free_area_empty(struct free_area *area, int migratetype)
{
return list_empty(&area->free_list[migratetype]);
}
/* Convert GFP flags to their corresponding migrate type */
#define GFP_MOVABLE_MASK (__GFP_RECLAIMABLE|__GFP_MOVABLE)
#define GFP_MOVABLE_SHIFT 3
static inline int gfp_migratetype(const gfp_t gfp_flags)
{
VM_WARN_ON((gfp_flags & GFP_MOVABLE_MASK) == GFP_MOVABLE_MASK);
BUILD_BUG_ON((1UL << GFP_MOVABLE_SHIFT) != ___GFP_MOVABLE);
BUILD_BUG_ON((___GFP_MOVABLE >> GFP_MOVABLE_SHIFT) != MIGRATE_MOVABLE);
BUILD_BUG_ON((___GFP_RECLAIMABLE >> GFP_MOVABLE_SHIFT) != MIGRATE_RECLAIMABLE);
BUILD_BUG_ON(((___GFP_MOVABLE | ___GFP_RECLAIMABLE) >>
GFP_MOVABLE_SHIFT) != MIGRATE_HIGHATOMIC);
if (unlikely(page_group_by_mobility_disabled))
return MIGRATE_UNMOVABLE;
/* Group based on mobility */
return (__force unsigned long)(gfp_flags & GFP_MOVABLE_MASK) >> GFP_MOVABLE_SHIFT;
}
#undef GFP_MOVABLE_MASK
#undef GFP_MOVABLE_SHIFT
bool decay_pcp_high(struct zone *zone, struct per_cpu_pages *pcp);
void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp);
void drain_all_pages(struct zone *zone);
void page_alloc_init_cpuhp(void);
void page_alloc_sysctl_init(void);
#endif /* __MM_PAGE_ALLOC_H */