-
Notifications
You must be signed in to change notification settings - Fork 0
/
Copy pathmm_explicit.c
356 lines (277 loc) · 12.5 KB
/
mm_explicit.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <unistd.h>
#include <string.h>
#include "mm.h"
#include "memlib.h"
/*********************************************************
* NOTE TO STUDENTS: Before you do anything else, please
* provide your team information in the following struct.
********************************************************/
team_t team = {
/* Team name */
"team6",
/* First member's full name */
"Songhee Lee",
/* First member's email address */
/* Second member's full name (leave blank if none) */
"",
/* Second member's email address (leave blank if none) */
""
};
#define ALIGNMENT 8
#define ALIGN(size) (((size) + (ALIGNMENT-1)) & ~0x7) // 가장 가까운 8의 배수로 올림
#define SIZE_T_SIZE (ALIGN(sizeof(size_t)))
#define WSIZE 4
#define DSIZE 8
#define MINIMUM 16 // Initial Prologue block size, header, footer, PREC, SUCC
#define CHUNKSIZE (1<<12)
#define MAX(x, y) ((x) > (y) ? (x) : (y))
#define PACK(size, alloc) ((size) | (alloc))
#define GET(p) (*(unsigned int*)(p))
#define PUT(p, val) (*(unsigned int*)(p) = (val))
#define GET_SIZE(p) (GET(p) & ~0x7)
#define GET_ALLOC(p) (GET(p) & 0x1)
/*
header, footer 포인터
다음 블럭 포인터 (주소 뒤)
이전 블럭 포인터 (주소 앞)
이전 가용 블럭의 bp를 가리키는 포인터
다음 가용 블럭의 bp를 가리키는 포인터
*/
#define HDRP(bp) ((char*)(bp) - WSIZE) // char* => 한 칸 씩 이동
#define FTRP(bp) ((char*)(bp) + GET_SIZE(HDRP(bp)) - DSIZE)
#define PREV_BLKP(bp) ((char*)(bp) - GET_SIZE(((char*)(bp) - DSIZE))) // (char*)(bp) - GET_SIZE(이전 블록의 풋터값)
#define NEXT_BLKP(bp) ((char*)(bp) + GET_SIZE(((char*)(bp) - WSIZE))) // (char*)(bp) + GET_SIZE(현재 블록의 헤더값)
/* Free List 상에서의 이전, 이후 블록의 포인터를 리턴한다. */
#define PREC_FREEP(bp) (*(void**)(bp)) // 이전 블록의 bp
#define SUCC_FREEP(bp) (*(void**)(bp + WSIZE)) // 이후 블록의 bp : bp에 들어있는 값
// **bp = pointer *bp bp를 따라가면 있는 값이 주소다. 주소를 값으로 갖는 것 = pointer
/* define searching method for find suitable free blocks to allocate*/
// #define NEXT_FIT // define하면 next_fit, 안 하면 first_fit으로 탐색
/* global variable & functions */
static char* heap_listp = NULL; // 항상 prologue block을 가리키는 정적 전역 변수
static char* free_listp = NULL; // free list의 맨 첫 블록을 가리키는 포인터
static void* extend_heap(size_t words);
static void* coalesce(void* bp);
static void* find_fit(size_t asize);
static void place(void* bp, size_t newsize);
int mm_init(void);
void *mm_malloc(size_t size);
void mm_free(void *bp);
void *mm_realloc(void *ptr, size_t size);
///////////////////////////////// Block information /////////////////////////////////////////////////////////
/*
A : Allocated? (1: true, 0:false)
RA : Reallocation tag (1: true, 0:false)
< Allocated Block >
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
Header : | size of the block | | | A|
bp ---> +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| |
| |
. Payload and padding .
. .
. .
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
Footer : | size of the block | | A|
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
< Free block >
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
Header : | size of the block | |RA| A|
bp ---> +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| pointer to its predecessor in Segregated list |
bp+WSIZE--> +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| pointer to its successor in Segregated list |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
. .
. .
. .
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
Footer : | size of the block | | A|
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
*/
///////////////////////////////// End of Block information /////////////////////////////////////////////////////////
//////////////////////////////////////// Helper functions //////////////////////////////////////////////////////////
/*
* mm_init - initialize the malloc package.
*/
static void* extend_heap(size_t words) {
char* bp;
size_t size;
/* 더블 워드 정렬에 따라 메모리를 mem_sbrk 함수를 이용해 할당받는다. */
size = (words % 2) ? (words + 1) * WSIZE : (words) * WSIZE; // size를 짝수 word && byte 형태로 만든다.
if ((long)(bp = mem_sbrk(size)) == -1) // 새 메모리의 첫 부분을 bp로 둔다. 주소값은 int로는 못 받아서 long으로 casting한 듯.
return NULL;
/* 새 가용 블록의 header와 footer를 정해주고 epilogue block을 가용 블록 맨 끝으로 옮긴다. */
PUT(HDRP(bp), PACK(size, 0)); // 헤더. 할당 안 해줬으므로 0으로.
PUT(FTRP(bp), PACK(size, 0)); // 풋터.
PUT(HDRP(NEXT_BLKP(bp)), PACK(0, 1)); // 새 에필로그 헤더
/* 만약 이전 블록이 가용 블록이라면 연결시킨다. */
return coalesce(bp);
}
static void *coalesce(void *bp)
{
size_t prev_alloc = GET_ALLOC(FTRP(PREV_BLKP(bp))); // 이전 블럭의 alloc은 footer에서
size_t next_alloc = GET_ALLOC(HDRP(NEXT_BLKP(bp))); // 다음 블럭의 alloc은 header에서
size_t size = GET_SIZE(HDRP(bp)); // 현재 블록의 header에서 size 정보 가져옴
// # Case 1 : 직전, 직후 블록 모두 할당 => 현재 블록만 free list에 넣어준다.
// # Case 2 : 직전 - 할당, 직후 - free
if (prev_alloc && !next_alloc){
remove_freed_block(NEXT_BLKP(bp));
size += GET_SIZE(HDRP(NEXT_BLKP(bp)));
PUT(HDRP(bp), PACK(size, 0)); // HDRP에 바뀐 size 정보 저장 -> FTRP에서 사용
PUT(FTRP(bp), PACK(size, 0)); // next block의 footer
}
// # Case 3 : 직전 - free, 직후 - alloc
else if (!prev_alloc && next_alloc){
remove_freed_block(PREV_BLKP(bp));
size += GET_SIZE(HDRP(PREV_BLKP(bp)));
bp = PREV_BLKP(bp);
PUT(HDRP(bp), PACK(size, 0));
PUT(FTRP(bp), PACK(size, 0)); // 현재 block의 header의 size 정보 이용하므로 순서 바뀌어도 상관 없을 것 같긴 한데 확인 해볼 것
}
// # Case 4 : 직전 - free, 직후 - free
else if (!prev_alloc && !next_alloc) {
remove_freed_block(PREV_BLKP(bp));
remove_freed_block(NEXT_BLKP(bp));
// size += GET_SIZE(HDRP(PREV_BLKP(bp))) +
// GET_SIZE(HDRP(NEXT_BLKP(bp)));
size += GET_SIZE(HDRP(PREV_BLKP(bp))) +
GET_SIZE(FTRP(NEXT_BLKP(bp)));
bp = PREV_BLKP(bp);
PUT(HDRP(bp), PACK(size, 0));
PUT(FTRP(bp), PACK(size, 0));
}
insert_freed_block(bp);
return bp;
}
void insert_freed_block(void *bp) {
SUCC_FREEP(bp) = free_listp; // 새로운 freed block의 succ = 현재 ptr
PREC_FREEP(bp) = NULL; // 새로운 freed block의 prec = NULL (가장 처음 삽입)
PREC_FREEP(free_listp) = bp; // 현재 freed block의 prec = 새로운 bp
free_listp = bp; // free_listp = 새로운 bp
}
void remove_freed_block(void *bp) {
// free list의 첫번째 블록을 없앨 때
if (bp == free_listp) {
PREC_FREEP(SUCC_FREEP(bp)) = NULL;
free_listp = SUCC_FREEP(bp);
}
else {
SUCC_FREEP(PREC_FREEP(bp)) = SUCC_FREEP(bp);
PREC_FREEP(SUCC_FREEP(bp)) = PREC_FREEP(bp);
}
}
static void *find_fit(size_t asize)
{
void *bp;
for (bp=free_listp; GET_ALLOC(HDRP(bp)) != 1; bp = SUCC_FREEP(bp)) {
if(asize <= GET_SIZE(HDRP(bp))) {
return bp;
}
}
return NULL;
}
static void place(void *bp, size_t asize) {
size_t csize = GET_SIZE(HDRP(bp));
remove_freed_block(bp);
if ((csize - asize) >= (2*DSIZE)) { // header와 footer의 공간을 확보해야하므로, 8바이트 이상
PUT(HDRP(bp), PACK(asize, 1));
PUT(FTRP(bp), PACK(asize, 1));
bp = NEXT_BLKP(bp);
PUT(HDRP(bp), PACK(csize - asize, 0));
PUT(FTRP(bp), PACK(csize - asize, 0));
insert_freed_block(bp);
}
else {
PUT(HDRP(bp), PACK(csize, 1));
PUT(FTRP(bp), PACK(csize, 1));
}
}
//////////////////////////////////////// End of Helper functions ////////////////////////////////////////
int mm_init(void)
{
if ((heap_listp = mem_sbrk(6*WSIZE)) == (void*)-1)
return -1;
PUT(heap_listp, 0);
PUT(heap_listp + (1*WSIZE), PACK(MINIMUM, 1));
PUT(heap_listp + (2*WSIZE), NULL);
PUT(heap_listp + (3*WSIZE), NULL);
PUT(heap_listp + (4*WSIZE), PACK(MINIMUM, 1));
PUT(heap_listp + (5*WSIZE), PACK(0, 1));
free_listp = heap_listp + 2*WSIZE;
if(extend_heap(CHUNKSIZE / WSIZE) == NULL)
return -1;
return 0;
}
void *mm_malloc(size_t size)
{
size_t asize;
size_t extendsize;
char *bp;
if (size == 0)
return NULL;
// if (size <= DSIZE)
// asize = 2*DSIZE; // 8 + 4(header) + 4(footer)
// else
// asize = DSIZE * ((size + (DSIZE) + (DSIZE-1)) / DSIZE);
asize = ALIGN(size + SIZE_T_SIZE);
if ((bp = find_fit(asize)) != NULL) {
place(bp, asize);
return bp;
}
extendsize = MAX(asize, CHUNKSIZE);
if ((bp = extend_heap(extendsize/WSIZE)) == NULL)
return NULL;
place(bp, asize);
return bp;
}
/*
* mm_malloc - Allocate a block by incrementing the brk pointer.
* Always allocate a block whose size is a multiple of the alignment.
*/
// void *mm_malloc(size_t size)
// {
// int newsize = ALIGN(size + SIZE_T_SIZE);
// void *p = mem_sbrk(newsize);
// if (p == (void *)-1)
// return NULL;
// else {
// *(size_t *)p = size;
// return (void *)((char *)p + SIZE_T_SIZE);
// }
// }
/*
* mm_free - Freeing a block does nothing.
*/
void mm_free(void *ptr) // ptr = bp
{
size_t size = GET_SIZE(HDRP(ptr));
PUT(HDRP(ptr), PACK(size, 0));
PUT(FTRP(ptr), PACK(size, 0));
coalesce(ptr);
}
/*
* mm_realloc - Implemented simply in terms of mm_malloc and mm_free
*/
void *mm_realloc(void *ptr, size_t size)
{
void *oldptr = ptr;
void *newptr;
size_t copySize;
newptr = mm_malloc(size);
if (newptr == NULL)
return NULL;
//copySize = GET_SIZE(HDRP(oldptr)) - DSIZE;
copySize = GET_SIZE(HDRP(oldptr));
if (size < copySize)
copySize = size;
memcpy(newptr, oldptr, copySize);
mm_free(oldptr);
return newptr;
}