diff options
Diffstat (limited to 'src/runtime/malloc.h')
-rw-r--r-- | src/runtime/malloc.h | 95 |
1 files changed, 1 insertions, 94 deletions
diff --git a/src/runtime/malloc.h b/src/runtime/malloc.h index 530dfc98f..8c48d05ef 100644 --- a/src/runtime/malloc.h +++ b/src/runtime/malloc.h @@ -253,100 +253,7 @@ void MCentral_Init(MCentral *c, int32 sizeclass); int32 MCentral_AllocList(MCentral *c, int32 n, MLink **first); void MCentral_FreeList(MCentral *c, int32 n, MLink *first); - -// Free(v) must be able to determine the MSpan containing v. -// The MHeapMap is a 3-level radix tree mapping page numbers to MSpans. -// -// NOTE(rsc): On a 32-bit platform (= 20-bit page numbers), -// we can swap in a 2-level radix tree. -// -// NOTE(rsc): We use a 3-level tree because tcmalloc does, but -// having only three levels requires approximately 1 MB per node -// in the tree, making the minimum map footprint 3 MB. -// Using a 4-level tree would cut the minimum footprint to 256 kB. -// On the other hand, it's just virtual address space: most of -// the memory is never going to be touched, thus never paged in. - -typedef struct MHeapMapNode2 MHeapMapNode2; -typedef struct MHeapMapNode3 MHeapMapNode3; - -enum -{ - // 64 bit address - 12 bit page size = 52 bits to map - MHeapMap_Level1Bits = 18, - MHeapMap_Level2Bits = 18, - MHeapMap_Level3Bits = 16, - - MHeapMap_TotalBits = - MHeapMap_Level1Bits + - MHeapMap_Level2Bits + - MHeapMap_Level3Bits, - - MHeapMap_Level1Mask = (1<<MHeapMap_Level1Bits) - 1, - MHeapMap_Level2Mask = (1<<MHeapMap_Level2Bits) - 1, - MHeapMap_Level3Mask = (1<<MHeapMap_Level3Bits) - 1, -}; - -struct MHeapMap -{ - void *(*allocator)(uintptr); - MHeapMapNode2 *p[1<<MHeapMap_Level1Bits]; -}; - -struct MHeapMapNode2 -{ - MHeapMapNode3 *p[1<<MHeapMap_Level2Bits]; -}; - -struct MHeapMapNode3 -{ - MSpan *s[1<<MHeapMap_Level3Bits]; -}; - -void MHeapMap_Init(MHeapMap *m, void *(*allocator)(uintptr)); -bool MHeapMap_Preallocate(MHeapMap *m, PageID k, uintptr npages); -MSpan* MHeapMap_Get(MHeapMap *m, PageID k); -MSpan* MHeapMap_GetMaybe(MHeapMap *m, PageID k); -void MHeapMap_Set(MHeapMap *m, PageID k, MSpan *v); - - -// Much of the time, free(v) needs to know only the size class for v, -// not which span it came from. The MHeapMap finds the size class -// by looking up the span. -// -// An MHeapMapCache is a simple direct-mapped cache translating -// page numbers to size classes. It avoids the expensive MHeapMap -// lookup for hot pages. -// -// The cache entries are 64 bits, with the page number in the low part -// and the value at the top. -// -// NOTE(rsc): On a machine with 32-bit addresses (= 20-bit page numbers), -// we can use a 16-bit cache entry by not storing the redundant 12 bits -// of the key that are used as the entry index. Here in 64-bit land, -// that trick won't work unless the hash table has 2^28 entries. -enum -{ - MHeapMapCache_HashBits = 12 -}; - -struct MHeapMapCache -{ - uintptr array[1<<MHeapMapCache_HashBits]; -}; - -// All macros for speed (sorry). -#define HMASK ((1<<MHeapMapCache_HashBits)-1) -#define KBITS MHeapMap_TotalBits -#define KMASK ((1LL<<KBITS)-1) - -#define MHeapMapCache_SET(cache, key, value) \ - ((cache)->array[(key) & HMASK] = (key) | ((uintptr)(value) << KBITS)) - -#define MHeapMapCache_GET(cache, key, tmp) \ - (tmp = (cache)->array[(key) & HMASK], \ - (tmp & KMASK) == (key) ? (tmp >> KBITS) : 0) - +#include "mheapmap64.h" // Main malloc heap. // The heap itself is the "free[]" and "large" arrays, |