improve 9.14, 9.17, 9.18 test case

chapter9/code/9.14.c

@@ -5,12 +5,12 @@
 #include <assert.h>
 #include "vm/csapp.h"
 
-int test(char* filename, char* content) {
+void test(char* filename, char* content) {
   int fd;
   char buf[20];
   fd = Open(filename, O_RDONLY, 0);
   Read(fd, buf, strlen(content));
-  return !strncmp(buf, content, strlen(content));
+  assert( !strncmp(buf, content, strlen(content)) );
 }
 
 int touch(char* filename, char* content) {
@@ -23,7 +23,7 @@ int touch(char* filename, char* content) {
 
 int main(int argc, char* argv[]) {
   touch("hello.txt", "Hello, world!");
-  assert(test("hello.txt", "Hello, world!"));
+  test("hello.txt", "Hello, world!");
 
   struct stat stat;
   int fd;
@@ -38,7 +38,7 @@ int main(int argc, char* argv[]) {
   *bufp = 'J';
   Munmap(bufp, size);
 
-  assert(test("hello.txt", "Jello, world!"));
+  test("hello.txt", "Jello, world!");
   return 0;
 }
 

chapter9/code/vm/9.17.c

@@ -2,23 +2,46 @@
  * 9.17.c
  */
 #include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
 #include "csapp.h"
 #include "mm.h"
 #include "memlib.h"
 
-#define LOOP 1000
+/*
+ * blk
+ * vvv
+ * 1      2      3         4
+ * +------+------+---------+---------+............
+ * ||||||||      |||||||||||         |............
+ * +------+------+---------+---------+............
+ *                         1         2
+ * ^^^
+ * new_blk
+ */
+int rand_num(void) {
+  return rand() % 10000;
+}
 
 int main(int argc, char* argv[]) {
-  int i;
-  for (i = 0; i < LOOP; i+=2) {
-    void* ptr_f = mm_malloc(i);
-    void* ptr = mm_malloc(i+1);
-    mm_free(ptr_f);
-  }
+
+  void* blk_1 = mm_malloc(rand_num());
+  void* blk_2 = mm_malloc(rand_num());
+  void* blk_3 = mm_malloc(rand_num());
+  void* blk_4 = mm_malloc(rand_num());
+  mm_free(blk_2);
+  mm_free(blk_4);
+
+  void* new_blk_1 = mm_malloc(rand_num());
+  void* new_blk_2 = mm_malloc(rand_num());
+
+  assert(new_blk_1 != blk_2);
+  assert(new_blk_1 == blk_4);
+  assert(new_blk_2 != blk_2);
+  assert(new_blk_2 != blk_4);
 
   return 0;
 }
 
 
 
-

chapter9/code/vm/9.18.c

@@ -2,19 +2,64 @@
  * 9.18.c
  */
 #include <stdio.h>
+#include <assert.h>
 #include "csapp.h"
 #include "mm.h"
 #include "memlib.h"
 
-#define LOOP 1000
+/*
+ * blk
+ * vvv
+ * 1       2           3
+ * +-------+-----------+---------+
+ * |||||||||           |||||||||||
+ * +-------+-----------+---------+
+ */
+
+// current block head
+unsigned int blk_head(void* blk) {
+  unsigned int * header = (unsigned int *)blk - 1;
+  return *header;
+}
+
+// previous block tail
+unsigned int prev_blk_tail(void* blk) {
+  unsigned int * prev_tail = (unsigned int *)blk - 2;
+  return *prev_tail;
+}
+
+// if block is allocated
+int blk_alloc(void* blk) {
+  return blk_head(blk) & 0x1;
+}
+
+// if previous block is allocated
+int blk_prev_alloc(void* blk) {
+  return (blk_head(blk) & 0x2) >> 1;
+}
+
+int rand_num(void) {
+  return rand() % 10000;
+}
 
 int main(int argc, char* argv[]) {
-  int i;
-  for (i = 0; i < LOOP; i+=2) {
-    void* ptr_f = mm_malloc(i);
-    void* ptr = mm_malloc(i+1);
-    mm_free(ptr_f);
-  }
+  void* blk_1 = mm_malloc(rand_num());
+  void* blk_2 = mm_malloc(rand_num());
+  void* blk_3 = mm_malloc(rand_num());
+  mm_free(blk_2);
+
+
+  assert(blk_alloc(blk_1));
+  assert(!blk_alloc(blk_2));
+  assert(blk_alloc(blk_3));
+
+  assert(blk_prev_alloc(blk_1));
+  assert(blk_prev_alloc(blk_2));
+  assert(!blk_prev_alloc(blk_3));
+
+
+  assert(blk_head(blk_1) != prev_blk_tail(blk_2));
+  assert(blk_head(blk_2) == prev_blk_tail(blk_3));
 
   return 0;
 }

chapter9/code/vm/makefile

@@ -1,14 +1,17 @@
 
 CC = gcc
 CFLAGS = -m64 -pthread -g
+SRCS.example = mm.c memlib.c csapp.c mm_first_fit.c
 SRCS.9.17 = mm.9.17.c memlib.c csapp.c 9.17.c
 SRCS.9.18 = mm.9.18.c memlib.c csapp.c 9.18.c
 
 all: diff
+	$(CC) $(CFLAGS) $(SRCS.example) -o mm_first_fit
 	$(CC) $(CFLAGS) $(SRCS.9.17) -o 9.17
 	$(CC) $(CFLAGS) $(SRCS.9.18) -o 9.18
 
 test:
+	./mm_first_fit
 	./9.17
 	./9.18
 

chapter9/code/vm/mm.9.18.c

@@ -138,6 +138,7 @@ void mm_free(void *bp)
   /* $begin mmfree */
 
   PUT(HDRP(bp), PACK(size, 0, GET_PREV_ALLOC(HDRP(bp))));
+  PUT(FTRP(bp), PACK(size, 0, GET_PREV_ALLOC(HDRP(bp))));
 
   if (GET_ALLOC(HDRP(NEXT_BLKP(bp))))
     PUT(HDRP(NEXT_BLKP(bp)), PACK(GET_SIZE(HDRP(NEXT_BLKP(bp))), 1, 0));

chapter9/code/vm/mm.9.18.diff

@@ -1,5 +1,5 @@
 --- mm.c	2017-11-09 02:57:43.679935907 +0000
-+++ mm.9.18.c	2017-11-09 02:57:43.679935907 +0000
++++ mm.9.18.c	2018-02-01 10:08:47.563747327 +0000
 @@ -20,7 +20,7 @@
  #define MAX(x, y) ((x) > (y)? (x) : (y))
 
@@ -44,13 +44,14 @@
 
    /* Search the free list for a fit */
    if ((bp = find_fit(asize)) != NULL) {  //line:vm:mm:findfitcall
-@@ -136,8 +137,15 @@
+@@ -136,8 +137,16 @@
    }
    /* $begin mmfree */
 
 -  PUT(HDRP(bp), PACK(size, 0));
 -  PUT(FTRP(bp), PACK(size, 0));
 +  PUT(HDRP(bp), PACK(size, 0, GET_PREV_ALLOC(HDRP(bp))));
++  PUT(FTRP(bp), PACK(size, 0, GET_PREV_ALLOC(HDRP(bp))));
 +
 +  if (GET_ALLOC(HDRP(NEXT_BLKP(bp))))
 +    PUT(HDRP(NEXT_BLKP(bp)), PACK(GET_SIZE(HDRP(NEXT_BLKP(bp))), 1, 0));
@@ -62,7 +63,7 @@
    coalesce(bp);
  }
 
-@@ -148,7 +156,7 @@
+@@ -148,7 +157,7 @@
  /* $begin mmfree */
  static void *coalesce(void *bp)
  {
@@ -71,7 +72,7 @@
    size_t next_alloc = GET_ALLOC(HDRP(NEXT_BLKP(bp)));
    size_t size = GET_SIZE(HDRP(bp));
 
-@@ -158,22 +166,22 @@
+@@ -158,22 +167,22 @@
 
    else if (prev_alloc && !next_alloc) {      /* Case 2 */
      size += GET_SIZE(HDRP(NEXT_BLKP(bp)));
@@ -100,7 +101,7 @@
      bp = PREV_BLKP(bp);
    }
    /* $end mmfree */
-@@ -246,9 +254,9 @@
+@@ -246,9 +255,9 @@
      return NULL;                                        //line:vm:mm:endextend
 
    /* Initialize free block header/footer and the epilogue header */
@@ -113,7 +114,7 @@
 
    /* Coalesce if the previous block was free */
    return coalesce(bp);                                          //line:vm:mm:returnblock
-@@ -267,15 +275,14 @@
+@@ -267,15 +276,14 @@
    size_t csize = GET_SIZE(HDRP(bp));
 
    if ((csize - asize) >= (2*DSIZE)) {

chapter9/code/vm/mm_first_fit.c

@@ -0,0 +1,52 @@
+/*
+ * mm_first_fit.c
+ *
+ * test example code from book section 9.9.12
+ */
+#include <stdio.h>
+#include <assert.h>
+#include "csapp.h"
+#include "mm.h"
+#include "memlib.h"
+
+/*
+ * blk
+ * vvv
+ * 1    2    3    4    5        6
+ * +----+----+----+----+--------+--------+
+ * |    ||||||    ||||||        ||||||||||
+ * +----+----+----+----+--------+--------+
+ * 1         3         2
+ * ^^^
+ * new_blk
+ */
+int main(int argc, char* argv[]) {
+
+  // allocate 8 bytes because of alignment
+  void* blk_1 = mm_malloc(1);
+  void* blk_2 = mm_malloc(1);
+
+  void* blk_3 = mm_malloc(8);
+  void* blk_4 = mm_malloc(8);
+  void* blk_5 = mm_malloc(16);
+  void* blk_6 = mm_malloc(16);
+
+  mm_free(blk_1);
+  mm_free(blk_3);
+  mm_free(blk_5);
+
+
+  void* new_blk_1 = mm_malloc(6);
+  void* new_blk_2 = mm_malloc(12);
+  void* new_blk_3 = mm_malloc(7);
+
+  assert(new_blk_1 == blk_1);
+  assert(new_blk_2 == blk_5);
+  assert(new_blk_3 == blk_3);
+
+  return 0;
+}
+
+
+
+

chapter9/index.md

@@ -26,8 +26,8 @@ test way:
 |9.14|9.14.c|assert|
 |9.15|----|----|
 |9.16|----|----|
-|9.17|vm/(mm.9.17, 9.17.c)|malloc and free|
-|9.18|vm/(mm.9.18, 9.18.c)|malloc and free|
+|9.17|vm/(mm.9.17, 9.17.c)|assert|
+|9.18|vm/(mm.9.18, 9.18.c)|assert|
 |9.19|----|----|
 |9.20|malloc/*|measure performance with std malloc|
 

review.md

@@ -11,7 +11,7 @@
 |6|----|----|
 |7|----|----|
 |8|----|----|
-|9|test 9.17, 9.18; more detailed reason for 9.19; 9.20 is awful, sub with more professional way(such as segrated fit method) |ing|
+|9|more detailed reason for 9.19; 9.20 is awful, sub with more professional way(such as segrated fit method) |ing|
 |10|----|----|
 |11|----|----|
 |12|----|----|