update readme; add copyright

README.md

@@ -92,4 +92,8 @@ Hello 观众朋友们大家好，这个Repo是我在做《深入理解计算机
 
 **2021-05-24** 线程级并行计算时，多处理器之间维护cache的一致性（coherence）。经典的MESI协议的实现：M - Exclusively Modified; E - Exclusively Clean; S - Shared Clean; I - Invalid. [video](https://www.bilibili.com/video/BV1zq4y1E7FE/), [git-commit](https://github.com/yangminz/bcst_csapp/commit/5a30fed6968dbf8570d89069795f8787294f06ae)
 
-**2021-06-06** 完善MESI协议的实现。拥有了多处理器之间的cache一致性，我们可以开始考虑多处理器多线程的资源共享问题。资源共享是各种问题的根源，但即便我们不考虑资源是否被正确地共享，由于MESI等cache协议，不恰当的共享会立即给性能带来极大的消耗。我们做一个简单的实验，多线程并行计算时，对同一个、相邻的、相距很远的物理地址进行读写，会得到不同的运算时间。这就是经典的伪共享（False Sharing）问题。 [video](https://www.bilibili.com/video/BV1xg411G7h2/), [git-commit](https://github.com/yangminz/bcst_csapp/commit/3e16dd4725098d1bfda3320d325dbf7c319741c3)
+**2021-06-06** 完善MESI协议的实现。拥有了多处理器之间的cache一致性，我们可以开始考虑多处理器多线程的资源共享问题。资源共享是各种问题的根源，但即便我们不考虑资源是否被正确地共享，由于MESI等cache协议，不恰当的共享会立即给性能带来极大的消耗。我们做一个简单的实验，多线程并行计算时，对同一个、相邻的、相距很远的物理地址进行读写，会得到不同的运算时间。这就是经典的伪共享（False Sharing）问题。 [video](https://www.bilibili.com/video/BV1xg411G7h2/), [git-commit](https://github.com/yangminz/bcst_csapp/commit/3e16dd4725098d1bfda3320d325dbf7c319741c3)
+
+**2021-06-14** 开始考虑虚拟内存（Virtual Machine）。对于先前的`va2pa`映射，我们考虑四种维护虚拟地址到物理地址的映射，并且要求都是O(1)时间复杂度：1. 使用`%`，对物理内存范围取余数，这也是目前为止，我们代码所采用的映射方法；2. 使用Hash Map，维护一个地址到地址的映射；3. 使用段表（Segment Table）；4. 使用页表（Page Table）。使用页表时，页表本身的存放也要占据物理内存，因此我们需要想办法减少页表本身占据的空间，否则我们要分配2^36条页表项，维护每一个虚拟页（Virtual Page）与物理页（Physical Page）之间的映射。这个方法就是多级页表。 [video](https://www.bilibili.com/video/BV1hq4y1L7bs/), [git-commit](https://github.com/yangminz/bcst_csapp/commit/f9323bdb94b18879a551df2ca8c5cfa1e75bf65b)
+
+**2021-06-20** 使用多级页表实现`va2pa`的映射。为此，我们首先需要确定每一个页表项（Page Table Entry）都储存怎样的信息。每一个VP与PP都占据4KB的大小，而一整张页表也同样这么大。4KB的一张页表维护512个次级页表的物理页号（Physical Page Number），每一项大小为8 Bytes。这8 Bytes，64 Bits中，几乎每一个Bit都有自己的含义，用于标识与控制。至此，我们大概了解了页表的数据结构，其实本质上是一个512叉树。对于这512叉树，它的根节点PPN通过控制寄存器`CR3`索引确定。 [video](https://www.bilibili.com/video/BV1hq4y1L7bs/), [git-commit](https://github.com/yangminz/bcst_csapp/commit/6c640bcb5975100eba147276df09e0fc10a1ffb0)

src/algorithm/bst.c

@@ -1,3 +1,13 @@
+/* BCST - Introduction to Computer Systems
+ * Author:      [email protected]
+ * Github:      https://github.com/yangminz/bcst_csapp
+ * Bilibili:    https://space.bilibili.com/4564101
+ * Zhihu:       https://www.zhihu.com/people/zhao-yang-min
+ * This project (code repository and videos) is exclusively owned by yangminz 
+ * and shall not be used for commercial and profitting purpose 
+ * without yangminz's permission.
+ */
+
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>

src/algorithm/redblack.c

@@ -1,3 +1,13 @@
+/* BCST - Introduction to Computer Systems
+ * Author:      [email protected]
+ * Github:      https://github.com/yangminz/bcst_csapp
+ * Bilibili:    https://space.bilibili.com/4564101
+ * Zhihu:       https://www.zhihu.com/people/zhao-yang-min
+ * This project (code repository and videos) is exclusively owned by yangminz 
+ * and shall not be used for commercial and profitting purpose 
+ * without yangminz's permission.
+ */
+
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>

src/headers/algorithm.h

@@ -1,140 +1,140 @@
-/* BCST - Introduction to Computer Systems
- * Author:      [email protected]
- * Github:      https://github.com/yangminz/bcst_csapp
- * Bilibili:    https://space.bilibili.com/4564101
- * Zhihu:       https://www.zhihu.com/people/zhao-yang-min
- * This project (code repository and videos) is exclusively owned by yangminz 
- * and shall not be used for commercial and profitting purpose 
- * without yangminz's permission.
- */
-
-// include guards to prevent double declaration of any identifiers 
-// such as types, enums and static variables
-#ifndef DATASTRUCTURE_GUARD
-#define DATASTRUCTURE_GUARD
-
-#include <stdint.h>
-
-/*======================================*/
-/*      Circular Doubly Linked List     */
-/*======================================*/
-typedef struct LINKED_LIST_NODE_STRUCT
-{
-    uint64_t value;
-    struct LINKED_LIST_NODE_STRUCT *prev;
-    struct LINKED_LIST_NODE_STRUCT *next;
-} linkedlist_node_t;
-
-typedef struct
-{
-    linkedlist_node_t  *head;
-    uint64_t    count;
-} linkedlist_t;
-
-linkedlist_t *linkedlist_construct();
-void linkedlist_free(linkedlist_t *list);
-linkedlist_t *linkedlist_add(linkedlist_t *list, uint64_t value);
-int linkedlist_delete(linkedlist_t *list, linkedlist_node_t *node);
-linkedlist_node_t *linkedlist_get(linkedlist_t *list, uint64_t value);
-linkedlist_node_t *linkedlist_next(linkedlist_t *list);
-
-/*======================================*/
-/*      Dynamic Array                   */
-/*======================================*/
-typedef struct
-{
-    uint32_t size;
-    uint32_t count;
-    uint64_t *table;
-} array_t;
-
-array_t *array_construct(int size);
-void array_free(array_t *arr);
-array_t *array_insert(array_t *arr, uint64_t value);
-int array_delete(array_t *arr, int index);
-int array_get(array_t *arr, int index, uint64_t *valptr);
-
-/*======================================*/
-/*      Extendible Hash Table           */
-/*======================================*/
-typedef struct
-{
-    int localdepth;     // the local depth
-    int counter;        // the counter of slots (have data)
-    char **karray;
-    uint64_t *varray;
-} hashtable_bucket_t;
-
-typedef struct
-{
-    int num;            // number of buckets = 1 << globaldepth
-    int globaldepth;    // the global depth
-
-    int size;           // the size of (key, value) tuples of each bucket
-    hashtable_bucket_t **directory;    // the internal table is actually an array
-} hashtable_t;
-
-hashtable_t *hashtable_construct(int size);
-void hashtable_free(hashtable_t *tab);
-int hashtable_get(hashtable_t *tab, char *key, uint64_t *valptr);
-hashtable_t *hashtable_insert(hashtable_t *tab, char *key, uint64_t val);
-
-/*======================================*/
-/*      Trie - Prefix Tree              */
-/*======================================*/
-typedef struct TRIE_NODE_STRUCT
-{
-    hashtable_t *next;
-    uint64_t value;
-    int isvalue;
-} trie_node_t;
-
-trie_node_t * trie_construct();
-void trie_free(trie_node_t *root);
-trie_node_t *trie_insert(trie_node_t *root, char *key, uint64_t value);
-int trie_get(trie_node_t *root, char *key, uint64_t *valptr);
-
-/*======================================*/
-/*      Red Black Tree                  */
-/*======================================*/
-typedef enum
-{
-    COLOR_RED,
-    COLOR_BLACK,
-} rb_color_t;
-
-typedef struct RB_NODE_STRUCT
-{
-    // pointers
-    struct RB_NODE_STRUCT *parent;
-
-    union
-    {
-        struct RB_NODE_STRUCT *childs[2];
-        struct
-        {
-            struct RB_NODE_STRUCT *left;        // childs[0]
-            struct RB_NODE_STRUCT *right;       // childs[1]
-        };
-    };
-
-    // edge color to parent
-    rb_color_t color;
-
-    // tree node value
-    uint64_t value;
-} rb_node_t;
-
-rb_node_t *rb_insert(rb_node_t *root, uint64_t val);
-rb_node_t *rb_delete(rb_node_t *root, uint64_t val);
-rb_node_t *rb_find(rb_node_t *root, uint64_t val);
-
-/*======================================*/
-/*      Binary Search Tree              */
-/*======================================*/
-
-rb_node_t *bst_insert(rb_node_t *root, uint64_t val);
-rb_node_t *bst_delete(rb_node_t *root, uint64_t val);
-rb_node_t *bst_find(rb_node_t *root, uint64_t val);
-
-#endif
+/* BCST - Introduction to Computer Systems
+ * Author:      [email protected]
+ * Github:      https://github.com/yangminz/bcst_csapp
+ * Bilibili:    https://space.bilibili.com/4564101
+ * Zhihu:       https://www.zhihu.com/people/zhao-yang-min
+ * This project (code repository and videos) is exclusively owned by yangminz 
+ * and shall not be used for commercial and profitting purpose 
+ * without yangminz's permission.
+ */
+
+// include guards to prevent double declaration of any identifiers 
+// such as types, enums and static variables
+#ifndef DATASTRUCTURE_GUARD
+#define DATASTRUCTURE_GUARD
+
+#include <stdint.h>
+
+/*======================================*/
+/*      Circular Doubly Linked List     */
+/*======================================*/
+typedef struct LINKED_LIST_NODE_STRUCT
+{
+    uint64_t value;
+    struct LINKED_LIST_NODE_STRUCT *prev;
+    struct LINKED_LIST_NODE_STRUCT *next;
+} linkedlist_node_t;
+
+typedef struct
+{
+    linkedlist_node_t  *head;
+    uint64_t    count;
+} linkedlist_t;
+
+linkedlist_t *linkedlist_construct();
+void linkedlist_free(linkedlist_t *list);
+linkedlist_t *linkedlist_add(linkedlist_t *list, uint64_t value);
+int linkedlist_delete(linkedlist_t *list, linkedlist_node_t *node);
+linkedlist_node_t *linkedlist_get(linkedlist_t *list, uint64_t value);
+linkedlist_node_t *linkedlist_next(linkedlist_t *list);
+
+/*======================================*/
+/*      Dynamic Array                   */
+/*======================================*/
+typedef struct
+{
+    uint32_t size;
+    uint32_t count;
+    uint64_t *table;
+} array_t;
+
+array_t *array_construct(int size);
+void array_free(array_t *arr);
+array_t *array_insert(array_t *arr, uint64_t value);
+int array_delete(array_t *arr, int index);
+int array_get(array_t *arr, int index, uint64_t *valptr);
+
+/*======================================*/
+/*      Extendible Hash Table           */
+/*======================================*/
+typedef struct
+{
+    int localdepth;     // the local depth
+    int counter;        // the counter of slots (have data)
+    char **karray;
+    uint64_t *varray;
+} hashtable_bucket_t;
+
+typedef struct
+{
+    int num;            // number of buckets = 1 << globaldepth
+    int globaldepth;    // the global depth
+
+    int size;           // the size of (key, value) tuples of each bucket
+    hashtable_bucket_t **directory;    // the internal table is actually an array
+} hashtable_t;
+
+hashtable_t *hashtable_construct(int size);
+void hashtable_free(hashtable_t *tab);
+int hashtable_get(hashtable_t *tab, char *key, uint64_t *valptr);
+hashtable_t *hashtable_insert(hashtable_t *tab, char *key, uint64_t val);
+
+/*======================================*/
+/*      Trie - Prefix Tree              */
+/*======================================*/
+typedef struct TRIE_NODE_STRUCT
+{
+    hashtable_t *next;
+    uint64_t value;
+    int isvalue;
+} trie_node_t;
+
+trie_node_t * trie_construct();
+void trie_free(trie_node_t *root);
+trie_node_t *trie_insert(trie_node_t *root, char *key, uint64_t value);
+int trie_get(trie_node_t *root, char *key, uint64_t *valptr);
+
+/*======================================*/
+/*      Red Black Tree                  */
+/*======================================*/
+typedef enum
+{
+    COLOR_RED,
+    COLOR_BLACK,
+} rb_color_t;
+
+typedef struct RB_NODE_STRUCT
+{
+    // pointers
+    struct RB_NODE_STRUCT *parent;
+
+    union
+    {
+        struct RB_NODE_STRUCT *childs[2];
+        struct
+        {
+            struct RB_NODE_STRUCT *left;        // childs[0]
+            struct RB_NODE_STRUCT *right;       // childs[1]
+        };
+    };
+
+    // edge color to parent
+    rb_color_t color;
+
+    // tree node value
+    uint64_t value;
+} rb_node_t;
+
+rb_node_t *rb_insert(rb_node_t *root, uint64_t val);
+rb_node_t *rb_delete(rb_node_t *root, uint64_t val);
+rb_node_t *rb_find(rb_node_t *root, uint64_t val);
+
+/*======================================*/
+/*      Binary Search Tree              */
+/*======================================*/
+
+rb_node_t *bst_insert(rb_node_t *root, uint64_t val);
+rb_node_t *bst_delete(rb_node_t *root, uint64_t val);
+rb_node_t *bst_find(rb_node_t *root, uint64_t val);
+
+#endif