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Felicia Seo 2022-11-14 15:32:08 -05:00
parent 2b68e9884e
commit 1d1c70c945
1 changed files with 15 additions and 62 deletions
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77
mm.c
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@ -16,9 +16,7 @@
* *
* Blocks have a payload which holds hold necessary data and a list_elem struct so blocks can be stored in lists * Blocks have a payload which holds hold necessary data and a list_elem struct so blocks can be stored in lists
*/ */
#include <string.h> #include <string.h>
#include <stdlib.h> #include <stdlib.h>
#include <assert.h> #include <assert.h>
@ -71,13 +69,11 @@ static struct list *free_lists[NUM_LISTS];
static size_t list_sizes[NUM_LISTS]; static size_t list_sizes[NUM_LISTS];
/* Function prototypes for internal helper routines */ /* Function prototypes for internal helper routines */
static struct block *extend_heap(size_t words, int realloc); static struct block *extend_heap(size_t words);
static void place(struct block *blck, size_t asize); static void place(struct block *blck, size_t asize);
static struct list* find_list(int not_empty, size_t size); static struct list* find_list(int not_empty, size_t size);
static struct block *find_fit(size_t num_words); static struct block *find_fit(size_t num_words);
//~ static void coalesce_free_lists();
static struct block *coalesce(struct block *bp); static struct block *coalesce(struct block *bp);
//~ static void print_lists();
/* Given a block, obtain previous's block footer. /* Given a block, obtain previous's block footer.
Works for left-most block also. */ Works for left-most block also. */
@ -132,6 +128,7 @@ static void set_block_used(struct block *blk, int size) {
/* Mark a block as free and set its size. */ /* Mark a block as free and set its size. */
static void set_block_free(struct block *blk, int size) { static void set_block_free(struct block *blk, int size) {
set_header_and_footer(blk, size, 0); set_header_and_footer(blk, size, 0);
list_push_front(find_list(0, size), &blk->elem);
} }
int mm_init(void) int mm_init(void)
@ -161,11 +158,16 @@ int mm_init(void)
free_lists[i] = current_list; free_lists[i] = current_list;
} }
for (int i = 0; i < NUM_LISTS; i++) for (int i = 0; i < NUM_LISTS; i++) {
list_sizes[i] = MIN_BLOCK_SIZE_WORDS * (i + 1); int size = 1;
for (int j = 0; j < i; j++) {
size *= 2;
}
list_sizes[i] = MIN_BLOCK_SIZE_WORDS * (size);
}
/* Extend the empty heap with a free block of CHUNKSIZE bytes */ /* Extend the empty heap with a free block of CHUNKSIZE bytes */
if (extend_heap(CHUNKSIZE, 0) == NULL) if (extend_heap(CHUNKSIZE) == NULL)
return -1; return -1;
return 0; return 0;
} }
@ -189,14 +191,8 @@ void *mm_malloc(size_t size) {
place(blck, words); place(blck, words);
return blck->payload; return blck->payload;
} }
//~ coalesce_free_lists();
//~ if ((blck = find_fit(words)) != NULL) {
//~ place(blck, words);
//~ return blck->payload;
//~ }
if ((blck = extend_heap(words, 0)) == NULL){ if ((blck = extend_heap(words)) == NULL){
return NULL; return NULL;
} }
place(blck, words); place(blck, words);
@ -215,22 +211,9 @@ void mm_free(void *bp)
set_block_free(blk, size); set_block_free(blk, size);
list_push_front(find_list(0, size), &blk->elem);
coalesce(blk); coalesce(blk);
} }
//~ static void coalesce_free_lists()
//~ {
//~ for (int i = 0; i < NUM_LISTS; i++) {
//~ struct list* current_list = &free_lists[i];
//~ for (struct list_elem* e = list_begin(current_list); e != list_end(current_list); e = list_next(e)) {
//~ struct block* bp = list_entry(e, struct block, elem);
//~ coalesce(bp);
//~ }
//~ }
//~ }
void *mm_realloc(void *ptr, size_t size) { void *mm_realloc(void *ptr, size_t size) {
size_t bytesize; size_t bytesize;
void *new_ptr; void *new_ptr;
@ -296,6 +279,7 @@ void *mm_realloc(void *ptr, size_t size) {
return new_ptr; return new_ptr;
} }
static struct block *coalesce(struct block *bp) static struct block *coalesce(struct block *bp)
{ {
bool prev_alloc = prev_blk_footer(bp)->inuse; /* is previous block allocated? */ bool prev_alloc = prev_blk_footer(bp)->inuse; /* is previous block allocated? */
@ -313,7 +297,6 @@ static struct block *coalesce(struct block *bp)
list_remove(&next_blk(bp)->elem); list_remove(&next_blk(bp)->elem);
size_t new_size = size + blk_size(next_blk(bp)); size_t new_size = size + blk_size(next_blk(bp));
set_block_free(bp, new_size); set_block_free(bp, new_size);
list_push_front(find_list(0, new_size), &bp->elem);
} }
else if (!prev_alloc && next_alloc) { /* Case 3 */ else if (!prev_alloc && next_alloc) { /* Case 3 */
@ -323,7 +306,6 @@ static struct block *coalesce(struct block *bp)
size_t new_size = blk_size(prev_blk(bp)) + size; size_t new_size = blk_size(prev_blk(bp)) + size;
bp = prev_blk(bp); bp = prev_blk(bp);
set_block_free(bp, new_size); set_block_free(bp, new_size);
list_push_front(find_list(0, new_size), &bp->elem);
} }
else { /* Case 4 */ else { /* Case 4 */
@ -334,7 +316,6 @@ static struct block *coalesce(struct block *bp)
size_t new_size = blk_size(prev_blk(bp)) + size + blk_size(next_blk(bp)); size_t new_size = blk_size(prev_blk(bp)) + size + blk_size(next_blk(bp));
bp = prev_blk(bp); bp = prev_blk(bp);
set_block_free(bp, new_size); set_block_free(bp, new_size);
list_push_front(find_list(0, new_size), &bp->elem);
} }
return bp; return bp;
} }
@ -343,7 +324,7 @@ static struct block *coalesce(struct block *bp)
* Extend heap with free block and return its block pointer * Extend heap with free block and return its block pointer
* Does not add new block to free list if called by realloc * Does not add new block to free list if called by realloc
*/ */
static struct block *extend_heap(size_t words, int realloc) static struct block *extend_heap(size_t words)
{ {
void *blck = mem_sbrk(words * WSIZE); void *blck = mem_sbrk(words * WSIZE);
@ -355,11 +336,6 @@ static struct block *extend_heap(size_t words, int realloc)
set_block_free(blk, words); set_block_free(blk, words);
next_blk(blk)->header = FENCE; next_blk(blk)->header = FENCE;
if (realloc) {
return blk;
}
list_push_front(find_list(0, words), &blk->elem);
return coalesce(blk); return coalesce(blk);
} }
@ -379,9 +355,6 @@ static void place(struct block *blck, size_t asize) {
set_block_used(blck, asize); set_block_used(blck, asize);
blck = next_blk(blck); blck = next_blk(blck);
set_block_free(blck, remaining_size); set_block_free(blck, remaining_size);
/* Add remaining free block back into list */
list_push_front(find_list(0, remaining_size), &blck->elem);
//~ print_lists(); //~ print_lists();
} }
else { else {
@ -398,7 +371,7 @@ static void place(struct block *blck, size_t asize) {
static struct list* find_list(int not_empty, size_t n_words) { static struct list* find_list(int not_empty, size_t n_words) {
for (int i = 0; i < NUM_LISTS; i++) { for (int i = 0; i < NUM_LISTS; i++) {
if ((n_words < list_sizes[i]) || (i == (NUM_LISTS - 1))) { if ((n_words <= list_sizes[i]) || (i == (NUM_LISTS - 1))) {
if (not_empty && list_empty(free_lists[i])) { if (not_empty && list_empty(free_lists[i])) {
continue; continue;
} }
@ -415,8 +388,6 @@ static struct block *find_fit(size_t num_words)
{ {
struct list* free_list = find_list(1, num_words); struct list* free_list = find_list(1, num_words);
//~ print_lists();
if (free_list == NULL) { if (free_list == NULL) {
return NULL; return NULL;
} }
@ -431,24 +402,6 @@ static struct block *find_fit(size_t num_words)
return NULL; return NULL;
} }
//~ static void print_lists()
//~ {
//~ for (int i = 0; i < NUM_LISTS; i++)
//~ {
//~ struct list *lp = free_lists[i];
//~ printf("Free List %d: ", i);
//~ for (struct list_elem *e = list_begin(lp); e != list_end(lp); e = list_next(e))
//~ {
//~ struct block *bp = list_entry(e, struct block, elem);
//~ printf("{inuse: %d, size: %d}\t", bp->header.inuse, bp->header.size);
//~ }
//~ printf("\n");
//~ }
//~ }
team_t team = { team_t team = {
"Micah Moore Felicia Seo", "Micah Moore Felicia Seo",
"Micah Moore", "Micah Moore",