diff options
| -rw-r--r-- | erts/emulator/beam/erl_alloc_util.c | 45 |
1 files changed, 30 insertions, 15 deletions
diff --git a/erts/emulator/beam/erl_alloc_util.c b/erts/emulator/beam/erl_alloc_util.c index d1335598b0..6ce872895b 100644 --- a/erts/emulator/beam/erl_alloc_util.c +++ b/erts/emulator/beam/erl_alloc_util.c @@ -118,7 +118,34 @@ static Uint max_mseg_carriers; ? ((CC).giga_no--, (CC).no = ONE_GIGA - 1) \ : (CC).no--) -/* ... */ +/* Multi block carrier (MBC) memory layout in R16: + +Empty MBC: +[Carrier_t|pad|Block_t L0T|fhdr| free... ] + +MBC after allocating first block: +[Carrier_t|pad|Block_t 000| udata |pad|Block_t L0T|fhdr| free... ] + +MBC after allocating second block: +[Carrier_t|pad|Block_t 000| udata |pad|Block_t 000| udata |pad|Block_t L0T|fhdr| free... ] + +MBC after deallocating first block: +[Carrier_t|pad|Block_t 00T|fhdr| free |FreeBlkFtr_t|Block_t 0P0| udata |pad|Block_t L0T|fhdr| free... ] + + + udata = Allocated user data + pad = Padding to ensure correct alignment for user data + fhdr = Allocator specific header to keep track of free block + free = Unused free memory + T = This block is free (THIS_FREE_BLK_HDR_FLG) + P = Previous block is free (PREV_FREE_BLK_HDR_FLG) + L = Last block in carrier (LAST_BLK_HDR_FLG) +*/ + +/* Single block carrier (SBC): +[Carrier_t|pad|Block_t 111| udata... ] +*/ + /* Blocks ... */ @@ -137,8 +164,7 @@ static Uint max_mseg_carriers; #define UMEM2BLK(P) ((Block_t *) (((char *) (P)) - ABLK_HDR_SZ)) #define BLK2UMEM(P) ((void *) (((char *) (P)) + ABLK_HDR_SZ)) -#define PREV_BLK_SZ(B) \ - ((UWord) (((FreeBlkFtr_t *)(B))[-1] & MBC_BLK_SZ_MASK)) +#define PREV_BLK_SZ(B) ((UWord) (((FreeBlkFtr_t *)(B))[-1])) #define SET_BLK_SZ_FTR(B, SZ) \ (((FreeBlkFtr_t *) (((char *) (B)) + (SZ)))[-1] = (SZ)) @@ -239,11 +265,6 @@ static Uint max_mseg_carriers; #define GET_BLK_HDR_FLGS(B) \ ((B)->bhdr & FLG_MASK) -#define SET_SBC_BLK_FTR(FTR) \ - ((FTR) = 0) -#define SET_MBC_BLK_FTR(FTR) \ - ((FTR) = 0) - #define IS_SBC_BLK(B) \ (((B)->bhdr & FLG_MASK) == SBC_BLK_HDR_FLG) #define IS_MBC_BLK(B) \ @@ -258,9 +279,7 @@ static Uint max_mseg_carriers; /* Carriers ... */ -#define SIZEOF_SBC_HDR (UNIT_CEILING(sizeof(Carrier_t) \ - + FBLK_FTR_SZ \ - + ABLK_HDR_SZ) \ +#define SIZEOF_SBC_HDR (UNIT_CEILING(sizeof(Carrier_t) + ABLK_HDR_SZ) \ - ABLK_HDR_SZ) #define MSEG_CARRIER_HDR_FLAG (((UWord) 1) << 0) @@ -1894,7 +1913,6 @@ create_sbmbc(Allctr_t *allctr, Uint umem_sz) blk_sz = UNIT_FLOOR(crr_sz - allctr->mbc_header_size); - SET_MBC_BLK_FTR(((FreeBlkFtr_t *) blk)[-1]); SET_MBC_BLK_HDR(blk, blk_sz, SBH_THIS_FREE|SBH_LAST_BLK, crr); link_carrier(&allctr->sbmbc_list, crr); @@ -2077,7 +2095,6 @@ create_carrier(Allctr_t *allctr, Uint umem_sz, UWord flags) blk = SBC2BLK(allctr, crr); - SET_SBC_BLK_FTR(((FreeBlkFtr_t *) blk)[-1]); SET_SBC_BLK_HDR(blk, blk_sz); link_carrier(&allctr->sbc_list, crr); @@ -2097,7 +2114,6 @@ create_carrier(Allctr_t *allctr, Uint umem_sz, UWord flags) blk_sz = UNIT_FLOOR(crr_sz - allctr->mbc_header_size); - SET_MBC_BLK_FTR(((FreeBlkFtr_t *) blk)[-1]); SET_MBC_BLK_HDR(blk, blk_sz, SBH_THIS_FREE|SBH_LAST_BLK, crr); if (flags & CFLG_MAIN_CARRIER) { @@ -4178,7 +4194,6 @@ erts_alcu_start(Allctr_t *allctr, AllctrInit_t *init) } #endif allctr->mbc_header_size = (UNIT_CEILING(allctr->mbc_header_size - + FBLK_FTR_SZ + ABLK_HDR_SZ) - ABLK_HDR_SZ); allctr->sbc_header_size = SIZEOF_SBC_HDR; |