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initial work on a two-level page-map

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This commit is contained in:
daanx 2024-12-21 23:08:52 -08:00
parent 1e2221f512
commit 56cbddfc7e
4 changed files with 206 additions and 13 deletions
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8
include/mimalloc/bits.h
View file

@ -68,6 +68,14 @@ typedef int32_t mi_ssize_t;
#define MI_MiB (MI_KiB*MI_KiB)
#define MI_GiB (MI_MiB*MI_KiB)
#if MI_INTPTR_SIZE > 4
#define MI_MAX_VABITS (48)
#define MI_PAGE_MAP_FLAT 0
#else
#define MI_MAX_VABITS (32)
#define MI_PAGE_MAP_FLAT 1
#endif
/* --------------------------------------------------------------------------------
Architecture

64
include/mimalloc/internal.h
View file

@ -422,6 +422,14 @@ static inline bool mi_heap_is_initialized(mi_heap_t* heap) {
return (heap != &_mi_heap_empty);
}
static inline mi_page_t* _mi_heap_get_free_small_page(mi_heap_t* heap, size_t size) {
mi_assert_internal(size <= (MI_SMALL_SIZE_MAX + MI_PADDING_SIZE));
const size_t idx = _mi_wsize_from_size(size);
mi_assert_internal(idx < MI_PAGES_DIRECT);
return heap->pages_free_direct[idx];
}
//static inline uintptr_t _mi_ptr_cookie(const void* p) {
// extern mi_heap_t _mi_heap_main;
// mi_assert_internal(_mi_heap_main.cookie != 0);
@ -433,14 +441,9 @@ static inline bool mi_heap_is_initialized(mi_heap_t* heap) {
Pages
----------------------------------------------------------- */
static inline mi_page_t* _mi_heap_get_free_small_page(mi_heap_t* heap, size_t size) {
mi_assert_internal(size <= (MI_SMALL_SIZE_MAX + MI_PADDING_SIZE));
const size_t idx = _mi_wsize_from_size(size);
mi_assert_internal(idx < MI_PAGES_DIRECT);
return heap->pages_free_direct[idx];
}
#if MI_PAGE_MAP_FLAT
// flat page-map committed on demand
extern uint8_t* _mi_page_map;
static inline uintptr_t _mi_page_map_index(const void* p) {
@ -465,16 +468,59 @@ static inline mi_page_t* _mi_ptr_page_ex(const void* p, bool* valid) {
static inline mi_page_t* _mi_checked_ptr_page(const void* p) {
bool valid;
mi_page_t* const page = _mi_ptr_page_ex(p,&valid);
mi_page_t* const page = _mi_ptr_page_ex(p, &valid);
return (valid ? page : NULL);
}
static inline mi_page_t* _mi_unchecked_ptr_page(const void* p) {
return _mi_ptr_page_ex(p, NULL);
}
#else
// 2-level page map
// one page-map directory = 64 KiB => covers 2^16 * 2^16 = 2^32 = 4 GiB address space
// the page-map needs 48-16-16 = 16 bits => 2^16 map directories = 2^16 * 2^3 = 2^19 = 512 KiB size.
// we commit the page-map directories on-demand. (2^16 * 2^16 = 2^32 ~= 4 GiB needed to cover 256 TeB)
#define MI_PAGE_MAP_SUB_SHIFT (16) // 64 KiB
#define MI_PAGE_MAP_SUB_SIZE (MI_ZU(1) << MI_PAGE_MAP_SUB_SHIFT)
#define MI_PAGE_MAP_SHIFT (MI_MAX_VABITS - MI_PAGE_MAP_SUB_SHIFT - MI_ARENA_SLICE_SHIFT)
#define MI_PAGE_MAP_COUNT (MI_ZU(1) << MI_PAGE_MAP_SHIFT)
extern uint8_t** _mi_page_map;
static inline size_t _mi_page_map_index(const void* p, size_t* sub_idx) {
const uintptr_t u = (uintptr_t)p / MI_ARENA_SLICE_SIZE;
if (sub_idx != NULL) { *sub_idx = (uint32_t)u % MI_PAGE_MAP_SUB_SIZE; }
return (size_t)(u / MI_PAGE_MAP_COUNT);
}
static inline mi_page_t* _mi_unchecked_ptr_page(const void* p) {
const uintptr_t u = (uintptr_t)p / MI_ARENA_SLICE_SIZE;
const uint8_t* const sub = _mi_page_map[u / MI_PAGE_MAP_COUNT];
const uint8_t ofs = sub[(uint32_t)u % MI_PAGE_MAP_SUB_SIZE];
return (mi_page_t*)((u - ofs + 1) * MI_ARENA_SLICE_SIZE);
}
static inline mi_page_t* _mi_checked_ptr_page(const void* p) {
const uintptr_t u = (uintptr_t)p / MI_ARENA_SLICE_SIZE;
const uint8_t* const sub = _mi_page_map[u / MI_PAGE_MAP_COUNT];
//if mi_unlikely(sub == NULL) { return NULL; }
const uint8_t ofs = sub[(uint32_t)u % MI_PAGE_MAP_SUB_SIZE];
//if mi_unlikely(ofs == 0) { return NULL; }
return (mi_page_t*)((u - ofs + 1) * MI_ARENA_SLICE_SIZE);
}
#endif
static inline mi_page_t* _mi_ptr_page(const void* p) {
mi_assert_internal(p==NULL || mi_is_in_heap_region(p));
#if MI_DEBUG || defined(__APPLE__)
return _mi_checked_ptr_page(p);
#else
return _mi_ptr_page_ex(p,NULL);
return _mi_unchecked_ptr_page(p);
#endif
}