Perf index = 57 (util) + 40 (thru) = 97/100
TuDatTr
parent
6d390de8a2
commit
b1a5273123
4
Makefile
4
Makefile
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@ -2,8 +2,8 @@
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# Students' Makefile for the Malloc Lab
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#
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CC = gcc
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# CFLAGS = -Wall -O2 -m32 -g03 -pg
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CFLAGS = -Wall -O0 -m32 -g03 -pg
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CFLAGS = -Wall -O2 -m32
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# CFLAGS = -Wall -O0 -m32 -g03 -pg
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OBJS = mdriver.o mm.o memlib.o fsecs.o fcyc.o clock.o ftimer.o
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355
mm.c
355
mm.c
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@ -89,6 +89,7 @@ team_t team = {
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/* Read and write a word at address p */
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#define GET(p) (*(unsigned int *)(p))
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#define PUT(p, val) (*(unsigned int *)(p) = (val))
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#define PUTT(p, val) (*(unsigned int *)(p) = (val))
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/* Read the size and allocated fields from address p */
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#define GET_SIZE(p) (GET(p) & ~0x7)
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@ -121,9 +122,7 @@ char* seg_list[LISTSIZE];
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///////////////////////////////// HELPER PREDEF ////////////////////////////////
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////////////////////////////////////////////////////////////////////////////////
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/* Page 856-858, Pearson R. Bryant – D. O’Hallaron. Computer Systems: A Programmer’s Perspective.3rd Edition, Pearson, 2003. */
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static void place(void *bp, size_t asize);
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/* Page 856, Pearson R. Bryant – D. O’Hallaron. Computer Systems: A Programmer’s Perspective.3rd Edition, Pearson, 2003. */
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static void* find_fit(size_t asize);
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static void* place(void *bp, size_t asize);
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/* Page 833, Pearson R. Bryant – D. O’Hallaron. Computer Systems: A Programmer’s Perspective.3rd Edition, Pearson, 2003. */
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static void* coalesce(void *bp);
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/* Page 831, Pearson R. Bryant – D. O’Hallaron. Computer Systems: A Programmer’s Perspective.3rd Edition, Pearson, 2003. */
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@ -132,152 +131,174 @@ static void add_free(void* bp, size_t asize);
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////////////////////////////////////////////////////////////////////////////////
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/////////////////////////////// HELPER FUNCTIONS ///////////////////////////////
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////////////////////////////////////////////////////////////////////////////////
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static int getSzClass(size_t asize) {
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for (size_t i = 0; i < LISTSIZE; ++i) {
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if (asize == (1 << i)) {
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return i;
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}
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}
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return LISTSIZE-1;
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}
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static void add_free(void* ptr, size_t size)
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static void *extend_heap(size_t size)
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{
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int szClass = getSzClass(size);
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void* classPtr = seg_list[szClass];
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while(classPtr != NULL)
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{
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classPtr = NXT_PTR(classPtr);
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}
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PUT_PTR(NXT_PTR(classPtr), ptr);
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PUT_PTR(PRV_PTR(ptr), classPtr);
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PUT_PTR(NXT_PTR(ptr), NULL);
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}
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static void place(void *bp, size_t asize)
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{
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size_t csize = GET_SIZE(HDRP(bp));
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if ((csize - asize) >= (2*DSIZE)) {
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PUT(HDRP(bp), PACK(asize, 1));
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PUT(FTRP(bp), PACK(asize, 1));
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bp = NEXT_BLKP(bp);
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PUT(HDRP(bp), PACK(csize-asize, 0));
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PUT(FTRP(bp), PACK(csize-asize, 0));
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}
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else {
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PUT(HDRP(bp), PACK(csize, 1));
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PUT(FTRP(bp), PACK(csize, 1));
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}
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}
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static void remove_free(void* bp) {
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int szClass = getSzClass(GET_SIZE(HDRP(bp)));
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if (PRV_BLK(bp) == NULL && NXT_BLK(bp) == NULL) {
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seg_list[szClass] = NULL;
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} else if (PRV_BLK(bp) != NULL && NXT_BLK(bp) == NULL) {
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PUT_PTR(PRV_PTR(PRV_BLK(bp)), NULL);
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seg_list[szClass] = PRV_BLK(bp);
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} else if (PRV_BLK(bp) == NULL && NXT_BLK(bp) != NULL) {
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PUT_PTR(PRV_PTR(NXT_BLK(bp)), NULL);
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} if (PRV_BLK(bp) != NULL && NXT_BLK(bp) != NULL) {
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PUT_PTR(NXT_PTR(PRV_BLK(bp)), NXT_BLK(bp));
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PUT_PTR(PRV_PTR(NXT_BLK(bp)), PRV_BLK(bp));
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}
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}
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static void* best_fit(void* ptr, size_t asize) {
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unsigned long left_over = GET_SIZE(ptr) - asize;
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void* bestfit = ptr;
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unsigned long best_left_over = GET_SIZE(ptr) - asize;
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while (NXT_PTR(ptr) != NULL) {
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left_over = GET_SIZE(ptr) - asize;
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if(left_over<best_left_over){
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best_left_over = left_over;
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bestfit=ptr;
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}
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ptr = NXT_BLK(ptr);
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}
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return bestfit;
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}
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/* Page 856, Pearson R. Bryant – D. O’Hallaron. Computer Systems: A Programmer’s Perspective.3rd Edition, Pearson, 2003. */
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static void* find_fit(size_t asize)
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{
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int szClass = getSzClass(asize);
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void* classPtr = seg_list[szClass];
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if (classPtr == NULL) {
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void *ptr;
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size_t asize; // Adjusted size
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asize = ALIGN(size);
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if ((ptr = mem_sbrk(asize)) == (void *)-1)
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return NULL;
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} else {
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if (szClass != LISTSIZE -1) {
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while (NXT_PTR(classPtr) != NULL) {
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classPtr = NXT_BLK(classPtr);
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}
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return classPtr;
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// Set headers and footer
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PUTT(HDRP(ptr), PACK(asize, 0));
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PUTT(FTRP(ptr), PACK(asize, 0));
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PUTT(HDRP(NEXT_BLKP(ptr)), PACK(0, 1));
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add_free(ptr, asize);
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return coalesce(ptr);
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}
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static void add_free(void *ptr, size_t size) {
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int list = 0;
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void *search_ptr = ptr;
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void *insert_ptr = NULL;
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// Select segregated list
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while ((list < LISTSIZE - 1) && (size > 1)) {
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size >>= 1;
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list++;
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}
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// Keep size ascending order and search
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search_ptr = seg_list[list];
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while ((search_ptr != NULL) && (size > GET_SIZE(HDRP(search_ptr)))) {
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insert_ptr = search_ptr;
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search_ptr = PRV_BLK(search_ptr);
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}
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// Set predecessor and successor
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if (search_ptr != NULL) {
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if (insert_ptr != NULL) {
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PUT_PTR(PRV_PTR(ptr), search_ptr);
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PUT_PTR(NXT_PTR(search_ptr), ptr);
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PUT_PTR(NXT_PTR(ptr), insert_ptr);
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PUT_PTR(PRV_PTR(insert_ptr), ptr);
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} else {
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return best_fit(classPtr, asize);
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PUT_PTR(PRV_PTR(ptr), search_ptr);
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PUT_PTR(NXT_PTR(search_ptr), ptr);
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PUT_PTR(NXT_PTR(ptr), NULL);
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seg_list[list] = ptr;
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}
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} else {
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if (insert_ptr != NULL) {
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PUT_PTR(PRV_PTR(ptr), NULL);
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PUT_PTR(NXT_PTR(ptr), insert_ptr);
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PUT_PTR(PRV_PTR(insert_ptr), ptr);
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} else {
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PUT_PTR(PRV_PTR(ptr), NULL);
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PUT_PTR(NXT_PTR(ptr), NULL);
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seg_list[list] = ptr;
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}
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}
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return;
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}
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/* Page 833, Pearson R. Bryant – D. O’Hallaron. Computer Systems: A Programmer’s Perspective.3rd Edition, Pearson, 2003. */
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static void *coalesce(void *bp) {
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size_t prev_alloc = GET_ALLOC(FTRP(PREV_BLKP(bp)));
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size_t next_alloc = GET_ALLOC(HDRP(NEXT_BLKP(bp)));
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size_t size = GET_SIZE(HDRP(bp));
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if (prev_alloc && next_alloc) { /* Case 1 */
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return bp;
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} else if (prev_alloc && !next_alloc) { /* Case 2 */
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remove_free(bp);
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remove_free(NEXT_BLKP(bp));
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size += GET_SIZE(HDRP(NEXT_BLKP(bp)));
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PUT(HDRP(bp),PACK(size,0));
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PUT(FTRP(bp),PACK(size,0));
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} else if (!prev_alloc && next_alloc) { /* Case 3 */
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remove_free(bp);
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remove_free(PREV_BLKP(bp));
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size += GET_SIZE(HDRP(PREV_BLKP(bp)));
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PUT(FTRP(bp), PACK(size, 0));
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PUT(HDRP(PREV_BLKP(bp)), PACK(size, 0));
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bp = PREV_BLKP(bp);
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} else { /* Case 4 */
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remove_free(bp);
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remove_free(PREV_BLKP(bp));
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remove_free(NEXT_BLKP(bp));
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size += GET_SIZE(HDRP(PREV_BLKP(bp))) +
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GET_SIZE(FTRP(NEXT_BLKP(bp)));
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PUT(HDRP(PREV_BLKP(bp)), PACK(size, 0));
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PUT(FTRP(NEXT_BLKP(bp)), PACK(size, 0));
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bp = PREV_BLKP(bp);
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static void delete_node(void *ptr) {
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int list = 0;
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size_t size = GET_SIZE(HDRP(ptr));
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// Select segregated list
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while ((list < LISTSIZE - 1) && (size > 1)) {
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size >>= 1;
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list++;
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}
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add_free(bp, size);
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return bp;
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if (PRV_BLK(ptr) != NULL) {
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if (NXT_BLK(ptr) != NULL) {
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PUT_PTR(NXT_PTR(PRV_BLK(ptr)), NXT_BLK(ptr));
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PUT_PTR(PRV_PTR(NXT_BLK(ptr)), PRV_BLK(ptr));
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} else {
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PUT_PTR(NXT_PTR(PRV_BLK(ptr)), NULL);
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seg_list[list] = PRV_BLK(ptr);
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}
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} else {
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if (NXT_BLK(ptr) != NULL) {
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PUT_PTR(PRV_PTR(NXT_BLK(ptr)), NULL);
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} else {
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seg_list[list] = NULL;
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}
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}
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return;
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}
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/* Page 831, Pearson R. Bryant – D. O’Hallaron. Computer Systems: A Programmer’s Perspective.3rd Edition, Pearson, 2003. */
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static void *extend_heap(size_t words)
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static void *coalesce(void *ptr)
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{
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char *bp;
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size_t size;
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size_t prev_alloc = GET_ALLOC(HDRP(PREV_BLKP(ptr)));
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size_t next_alloc = GET_ALLOC(HDRP(NEXT_BLKP(ptr)));
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size_t size = GET_SIZE(HDRP(ptr));
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/* Allocate an even number of words to maintain alignment */
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size = (words % 2) ? (words+1) * WSIZE : words * WSIZE;
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if ((long)(bp = mem_sbrk(size)) == -1)
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return NULL;
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if (prev_alloc && next_alloc) { // Case 1
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return ptr;
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}
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else if (prev_alloc && !next_alloc) { // Case 2
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delete_node(ptr);
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delete_node(NEXT_BLKP(ptr));
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size += GET_SIZE(HDRP(NEXT_BLKP(ptr)));
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PUT(HDRP(ptr), PACK(size, 0));
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PUT(FTRP(ptr), PACK(size, 0));
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} else if (!prev_alloc && next_alloc) { // Case 3
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delete_node(ptr);
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delete_node(PREV_BLKP(ptr));
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size += GET_SIZE(HDRP(PREV_BLKP(ptr)));
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PUT(FTRP(ptr), PACK(size, 0));
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PUT(HDRP(PREV_BLKP(ptr)), PACK(size, 0));
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ptr = PREV_BLKP(ptr);
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} else { // Case 4
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delete_node(ptr);
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delete_node(PREV_BLKP(ptr));
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delete_node(NEXT_BLKP(ptr));
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size += GET_SIZE(HDRP(PREV_BLKP(ptr))) + GET_SIZE(HDRP(NEXT_BLKP(ptr)));
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PUT(HDRP(PREV_BLKP(ptr)), PACK(size, 0));
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PUT(FTRP(NEXT_BLKP(ptr)), PACK(size, 0));
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ptr = PREV_BLKP(ptr);
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}
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add_free(ptr, size);
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return ptr;
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}
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/* Initialize free block header/footer and the epilogue header */
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PUT(HDRP(bp), PACK(size,0)); /* Free block header */
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PUT(FTRP(bp), PACK(size,0)); /* Free block footer */
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PUT(HDRP(NEXT_BLKP(bp)), PACK(0, 1)); /* New epilogue header */
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add_free(bp, size);
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/* Coalesce if the previous block was free */
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return coalesce(bp);
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static void *place(void *ptr, size_t asize)
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{
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size_t ptr_size = GET_SIZE(HDRP(ptr));
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size_t remainder = ptr_size - asize;
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delete_node(ptr);
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if (remainder <= DSIZE * 2) {
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// Do not split block
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PUT(HDRP(ptr), PACK(ptr_size, 1));
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PUT(FTRP(ptr), PACK(ptr_size, 1));
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}
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else if (asize >= 100) {
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// Split block
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PUT(HDRP(ptr), PACK(remainder, 0));
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PUT(FTRP(ptr), PACK(remainder, 0));
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PUTT(HDRP(NEXT_BLKP(ptr)), PACK(asize, 1));
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PUTT(FTRP(NEXT_BLKP(ptr)), PACK(asize, 1));
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add_free(ptr, remainder);
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return NEXT_BLKP(ptr);
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}
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else {
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// Split block
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PUT(HDRP(ptr), PACK(asize, 1));
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PUT(FTRP(ptr), PACK(asize, 1));
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PUTT(HDRP(NEXT_BLKP(ptr)), PACK(remainder, 0));
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PUTT(FTRP(NEXT_BLKP(ptr)), PACK(remainder, 0));
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add_free(NEXT_BLKP(ptr), remainder);
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}
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return ptr;
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}
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////////////////////////////////////////////////////////////////////////////////
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@ -316,32 +337,54 @@ int mm_init(void)
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*/
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void *mm_malloc(size_t size)
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{
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size_t asize; /* Adjusted block size */
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size_t asize; /* Adjusted block size */
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size_t extendsize; /* Amount to extend heap if no fit */
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char *bp; /* Pointer */
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/* Ignore spurious requests */
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void *ptr = NULL; /* Pointer */
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// Ignore size 0 cases
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if (size == 0)
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return NULL;
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/* Adjust block size to include overhead and alignment reqs. */
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if (size <= DSIZE)
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asize = 2*DSIZE;
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else
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// Align block size
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if (size <= DSIZE) {
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asize = 2 * DSIZE;
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} else {
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asize = ALIGN(size+DSIZE);
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/* Search the free list for a fit */
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if ((bp = find_fit(asize)) != NULL) {
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place(bp, asize);
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return bp;
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}
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/* No fit found. Get more memory and place the block */
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extendsize = MAX(asize,CHUNKSIZE);
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if ((bp = extend_heap(extendsize/WSIZE)) == NULL)
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return NULL;
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place(bp, asize);
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return bp;
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int list = 0;
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size_t searchsize = asize;
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// Search for free block in segregated list
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while (list < LISTSIZE) {
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if ((list == LISTSIZE- 1) || ((searchsize <= 1) && (seg_list[list] != NULL))) {
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ptr = seg_list[list];
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// Ignore blocks that are too small or marked with the reallocation bit
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while ((ptr != NULL) && (asize > GET_SIZE(HDRP(ptr))))
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{
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ptr = PRV_BLK(ptr);
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}
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if (ptr != NULL)
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break;
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}
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searchsize >>= 1;
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list++;
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}
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// if free block is not found, extend the heap
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if (ptr == NULL) {
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extendsize = MAX(asize, CHUNKSIZE);
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if ((ptr = extend_heap(extendsize)) == NULL)
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return NULL;
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}
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// Place and divide block
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ptr = place(ptr, asize);
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// Return pointer to newly allocated block
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return ptr;
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}
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/* Page 833, Pearson R. Bryant – D. O’Hallaron. Computer Systems: A Programmer’s Perspective.3rd Edition, Pearson, 2003. */
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