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Folio

include/mem/folio.h View source View on GitHub

Structs

Section titled “Structs”

folio

Section titled “folio”
struct folio (8 fields) source
§ struct page *base_page
§ atomic(enum folio_flags) flags
§ uint8_t order

2^order pages

§ refcount_t refcount
§ mapcount_t mapcount
§ void *mapping

tagged, anon_vma or file_vma_range

§ pgoff_t index
§ struct list_node lru

reclaim linkage

Enums

Section titled “Enums”

folio_flags

Section titled “folio_flags”
enum folio_flags : uint32_t (7 variants) source

folio_flags: 32-bit bitflags

     ┌────────────────────────────────────┐
Bits │  31..8                 7..4   3..0 │
Use  │  (reserved)            ..LU   DMAO │
     └────────────────────────────────────┘

O - On an LRU / reclaim list A - Anon: mapping is an anon_vma (clear => file_vma_range) M - Mapped at least once (mapcount has been nonzero) D - Dirty: needs writeback U - Uptodate: contents valid L - Locked: I/O in flight

Reserved bits fill in as the pager arrives (writeback, referenced, reclaim, mlocked, swapbacked, …). Width is uint32_t for headroom.

§ FOLIO_FLAGS_NONE = 0
§ FOLIO_FLAG_ON_LRU = (1u << 0)
§ FOLIO_FLAG_ANON = (1u << 1)
§ FOLIO_FLAG_MAPPED = (1u << 2)
§ FOLIO_FLAG_DIRTY = (1u << 3)
§ FOLIO_FLAG_UPTODATE = (1u << 4)
§ FOLIO_FLAG_LOCKED = (1u << 5)

folio_tag

Section titled “folio_tag”
enum folio_tag : uintptr_t (2 variants) source
§ FOLIO_TAG_ADDRESS_SPACE = 1
§ FOLIO_TAG_ANON = 2

Functions

Section titled “Functions”

page_get_folio_index

Section titled “page_get_folio_index”
uint32_t page_get_folio_index(struct page *p)
source

page_is_folio_head

Section titled “page_is_folio_head”
bool page_is_folio_head(struct page *p)
source

folio_alloc_folio_struct

Section titled “folio_alloc_folio_struct”
struct folio * folio_alloc_folio_struct(void)
source

folio_free_folio_struct

Section titled “folio_free_folio_struct”
void folio_free_folio_struct(struct folio *f)
source

folio_alloc_full

Section titled “folio_alloc_full”
struct folio * folio_alloc_full(
    uint8_t order,
    struct alloc_params params
)
source

folio_free

Section titled “folio_free”
void folio_free(struct folio *folio)
source

folio_bind_pages

Section titled “folio_bind_pages”
void folio_bind_pages(struct folio *f)
source

page <-> folio backptrs, give every struct page folio at alloc, clear them at free

folio_unbind_pages

Section titled “folio_unbind_pages”
void folio_unbind_pages(struct folio *f)
source

folio_zero

Section titled “folio_zero”
void folio_zero(struct folio *f)
source

Operates on the data pages

folio_copy

Section titled “folio_copy”
void folio_copy(const struct folio *src, struct folio *dst)
source

LRU

folio_add_lru

Section titled “folio_add_lru”
void folio_add_lru(struct folio *f)
source

folio_del_lru

Section titled “folio_del_lru”
void folio_del_lru(struct folio *f)
source

page_set_folio

Section titled “page_set_folio”
void page_set_folio(struct page *p, struct folio *f)
source

Some struct page functions here for folio

page_get_folio

Section titled “page_get_folio”
struct folio * page_get_folio(const struct page *p)
source

page_clear_folio

Section titled “page_clear_folio”
void page_clear_folio(struct page *p)
source

folio_mapped

Section titled “folio_mapped”
bool folio_mapped(const struct folio *f)
source

folio_nr_pages

Section titled “folio_nr_pages”
unsigned long folio_nr_pages(const struct folio *f)
source

folio_set_tag

Section titled “folio_set_tag”
void folio_set_tag(struct folio *f, enum folio_tag t)
source

folio_get_tag

Section titled “folio_get_tag”
enum folio_tag folio_get_tag(const struct folio *f)
source

folio_test_flag

Section titled “folio_test_flag”
bool folio_test_flag(const struct folio *f, enum folio_flags m)
source

folio_set_flag

Section titled “folio_set_flag”
void folio_set_flag(struct folio *f, enum folio_flags m)
source

folio_clear_flag

Section titled “folio_clear_flag”
void folio_clear_flag(struct folio *f, enum folio_flags m)
source

folio_test_set_flag

Section titled “folio_test_set_flag”
bool folio_test_set_flag(struct folio *f, enum folio_flags m)
source

folio_getref

Section titled “folio_getref”
bool folio_getref(struct folio *f)
source

folio_putref

Section titled “folio_putref”
void folio_putref(struct folio *f)
source

folio_get_page

Section titled “folio_get_page”
struct page * folio_get_page(const struct folio *f, size_t n)
source

Nth page

folio_get_pfn

Section titled “folio_get_pfn”
pfn_t folio_get_pfn(const struct folio *f)
source

folio_from_page

Section titled “folio_from_page”
struct folio * folio_from_page(const struct page *p)
source

reverse of folio_page(): a mapped frame -> its folio, via the page backpointer. The fault/rmap paths take a PTE’s phys and land back here.

folio_from_paddr

Section titled “folio_from_paddr”
struct folio * folio_from_paddr(paddr_t pa)
source

folio_get_paddr

Section titled “folio_get_paddr”
paddr_t folio_get_paddr(const struct folio *f)
source

folio_get_vaddr

Section titled “folio_get_vaddr”
vaddr_t folio_get_vaddr(const struct folio *f)
source

HHDM map of base

folio_get_paddr_for

Section titled “folio_get_paddr_for”
paddr_t folio_get_paddr_for(const struct folio *f, size_t n)
source

folio_get_vaddr_for

Section titled “folio_get_vaddr_for”
vaddr_t folio_get_vaddr_for(const struct folio *f, size_t n)
source

HHDM map of page n

folio_mark_dirty

Section titled “folio_mark_dirty”
void folio_mark_dirty(struct folio *f)
source

state

folio_mark_uptodate

Section titled “folio_mark_uptodate”
void folio_mark_uptodate(struct folio *f)
source

folio_set_anon

Section titled “folio_set_anon”
void folio_set_anon(
    struct folio *f,
    struct anon_vma *av,
    pgoff_t index
)
source

folio_is_anon

Section titled “folio_is_anon”
bool folio_is_anon(const struct folio *f)
source

folio_is_file_vma_range

Section titled “folio_is_file_vma_range”
bool folio_is_file_vma_range(const struct folio *f)
source

folio_get_anon_vma

Section titled “folio_get_anon_vma”
struct anon_vma * folio_get_anon_vma(const struct folio *f)
source

folio_get_file_vma_range

Section titled “folio_get_file_vma_range”
struct file_vma_range * folio_get_file_vma_range(const struct folio *f)
source

folio_trylock

Section titled “folio_trylock”
bool folio_trylock(struct folio *f)
source

folio_lock

Section titled “folio_lock”
void folio_lock(struct folio *f)
source

folio_unlock

Section titled “folio_unlock”
void folio_unlock(struct folio *f)
source

folio_mapcount_inc

Section titled “folio_mapcount_inc”
void folio_mapcount_inc(struct folio *f)
source

mapcount, number of PTEs pointing at this folio

folio_mapcount_dec

Section titled “folio_mapcount_dec”
bool folio_mapcount_dec(struct folio *f)
source

Macros

Section titled “Macros”

FOLIO_TAG_BITS

Section titled “FOLIO_TAG_BITS”
#define FOLIO_TAG_BITS 0x7
source

folio_for_each_page_struct

Section titled “folio_for_each_page_struct”
#define folio_for_each_page_struct(p_, f_)
source
Expansion
#define folio_for_each_page_struct(p_, f_) \
    for (size_t __folio_page_idx = 0; \
         __folio_page_idx < folio_nr_pages(f_) && \
         (((p_) = folio_get_page((f_), __folio_page_idx)), true); \
         __folio_page_idx++)

folio_for_each_page_paddr

Section titled “folio_for_each_page_paddr”
#define folio_for_each_page_paddr(p_, f_)
source
Expansion
#define folio_for_each_page_paddr(p_, f_) \
    for (size_t __folio_paddr_idx = 0; \
         __folio_paddr_idx < folio_nr_pages(f_) && \
         (((p_) = folio_get_paddr_for((f_), __folio_paddr_idx)), true); \
         __folio_paddr_idx++)

folio_for_each_page_vaddr

Section titled “folio_for_each_page_vaddr”
#define folio_for_each_page_vaddr(p_, f_)
source
Expansion
#define folio_for_each_page_vaddr(p_, f_) \
    for (size_t __folio_vaddr_idx = 0; \
         __folio_vaddr_idx < folio_nr_pages(f_) && \
         (((p_) = folio_get_vaddr_for((f_), __folio_vaddr_idx)), true); \
         __folio_vaddr_idx++)

folio_alloc

Section titled “folio_alloc”
#define folio_alloc(order, ...)
source
Expansion
#define folio_alloc(order, ...) \
    folio_alloc_full((order), alloc_params_with_defaults( \
                                  ALLOC_FLAGS_DEFAULT, ALLOC_BEHAVIOR_DEFAULT, \
                                  ##__VA_ARGS__))