On (02/19/16 14:38), Sergey Senozhatsky wrote: [..] > #define OBJ_ALLOCATED_TAG 1 > #define OBJ_TAG_BITS 1 > #define OBJ_INDEX_BITS (BITS_PER_LONG - _PFN_BITS - OBJ_TAG_BITS) > #define OBJ_INDEX_MASK ((_AC(1, UL) << OBJ_INDEX_BITS) - 1) > > #define ZS_MIN_ALLOC_SIZE \ > MAX(32, (ZS_MAX_PAGES_PER_ZSPAGE << PAGE_SHIFT >> OBJ_INDEX_BITS)) [..] > -- on 32 bit system, PAGE_SHIFT 12 > > ZS_MAX_PAGES_PER_ZSPAGE 1 << 4 16 > OBJ_INDEX_BITS (32 - (32 - 12) - 1) 11 > OBJ_INDEX_MASK ((1 << (32 - (32 - 12) - 1)) - 1) 2047 > ZS_MIN_ALLOC_SIZE MAX(32, ((1 << 4) << 12 >> (32 - (32 - 12) - 1))) 32 > > -- on 64 bit system, PAGE_SHIFT 12 > > ZS_MAX_PAGES_PER_ZSPAGE 1 << 4 16 > OBJ_INDEX_BITS (64 - (64 - 12) - 1) 11 > OBJ_INDEX_MASK ((1 << (64 - (64 - 12) - 1)) - 1) 2047 > ZS_MIN_ALLOC_SIZE MAX(32, ((1 << 4) << 12 >> (64 - (64 - 12) - 1))) 32 even if it's missing "HANDLE_PIN_BIT 0", it's still OBJ_INDEX_BITS 10, 2<<10 should be enough to keep 32 bytes class around. > -- on 64 bit system, PAGE_SHIFT 14 > > ZS_MAX_PAGES_PER_ZSPAGE 1 << 4 16 > OBJ_INDEX_BITS (64 - (64 - 14) - 1) 13 > OBJ_INDEX_MASK ((1 << (64 - (64 - 14) - 1)) - 1) 8191 > ZS_MIN_ALLOC_SIZE MAX(32, ((1 << 4) << 14 >> (64 - (64 - 14) - 1))) 32 OBJ_INDEX_BITS 2<<12 still looks to be good enough. -ss -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>