Merge branch 'patch-support-run-first-demo-on-dragonos' of github.com:DragonOS-Community/relibc into patch-support-run-first-demo-on-dragonos

src/c/malloc.c

@@ -0,0 +1,412 @@
+// Copyright (C) DragonOS Community  longjin
+
+// This program is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License
+// as published by the Free Software Foundation; either version 2
+// of the License, or (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software
+// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+// Or you can visit https://www.gnu.org/licenses/gpl-2.0.html
+
+#include <unistd.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdint.h>
+
+#define PAGE_4K_SHIFT 12
+#define PAGE_2M_SHIFT 21
+#define PAGE_1G_SHIFT 30
+#define PAGE_GDT_SHIFT 39
+
+
+
+/***************************/
+
+// 不同大小的页的容量
+#define PAGE_4K_SIZE (1UL << PAGE_4K_SHIFT)
+#define PAGE_2M_SIZE (1UL << PAGE_2M_SHIFT)
+#define PAGE_1G_SIZE (1UL << PAGE_1G_SHIFT)
+
+// 屏蔽低于x的数值
+#define PAGE_4K_MASK (~(PAGE_4K_SIZE - 1))
+#define PAGE_2M_MASK (~(PAGE_2M_SIZE - 1))
+
+// 将addr按照x的上边界对齐
+//#define PAGE_4K_ALIGN(addr) (((unsigned long)(addr) + PAGE_4K_SIZE - 1) & PAGE_4K_MASK)
+//#define PAGE_2M_ALIGN(addr) (((unsigned long)(addr) + PAGE_2M_SIZE - 1) & PAGE_2M_MASK)
+
+/**
+ * @brief 显式链表的结点
+ *
+ */
+typedef struct malloc_mem_chunk_t
+{
+    uint64_t length;                 // 整个块所占用的内存区域的大小
+    uint64_t padding;
+    struct malloc_mem_chunk_t *prev; // 上一个结点的指针
+    struct malloc_mem_chunk_t *next; // 下一个结点的指针
+} malloc_mem_chunk_t;
+
+static uint64_t brk_base_addr = 0;    // 堆区域的内存基地址
+static uint64_t brk_max_addr = 0;     // 堆区域的内存最大地址
+static uint64_t brk_managed_addr = 0; // 堆区域已经被管理的地址
+
+// 空闲链表
+//  按start_addr升序排序
+static malloc_mem_chunk_t *malloc_free_list = NULL;
+static malloc_mem_chunk_t *malloc_free_list_end = NULL; // 空闲链表的末尾结点
+
+static uint64_t count_last_free_size = 0; // 统计距离上一次回收内存，已经free了多少内存
+
+/**
+ * @brief 将块插入空闲链表
+ *
+ * @param ck 待插入的块
+ */
+static void malloc_insert_free_list(malloc_mem_chunk_t *ck);
+
+/**
+ * @brief 当堆顶空闲空间大于2个页的空间的时候，释放1个页
+ *
+ */
+static void release_brk();
+
+/**
+ * @brief 在链表中检索符合要求的空闲块（best fit）
+ *
+ * @param size 块的大小
+ * @return malloc_mem_chunk_t*
+ */
+static malloc_mem_chunk_t *malloc_query_free_chunk_bf(uint64_t size)
+{
+    // 在满足best fit的前提下，尽可能的使分配的内存在低地址
+    //  使得总的堆内存可以更快被释放
+
+    if (malloc_free_list == NULL)
+    {
+        return NULL;
+    }
+    malloc_mem_chunk_t *ptr = malloc_free_list;
+    malloc_mem_chunk_t *best = NULL;
+    // printf("query size=%d", size);
+    while (ptr != NULL)
+    {
+        // printf("ptr->length=%#010lx\n", ptr->length);
+        if (ptr->length == size)
+        {
+            best = ptr;
+            break;
+        }
+
+        if (ptr->length > size)
+        {
+            if (best == NULL)
+                best = ptr;
+            else if (best->length > ptr->length)
+                best = ptr;
+        }
+        ptr = ptr->next;
+    }
+
+    return best;
+}
+
+/**
+ * @brief 在链表中检索符合要求的空闲块（first fit）
+ *
+ * @param size
+ * @return malloc_mem_chunk_t*
+ */
+static malloc_mem_chunk_t *malloc_query_free_chunk_ff(uint64_t size)
+{
+    if (malloc_free_list == NULL)
+        return NULL;
+    malloc_mem_chunk_t *ptr = malloc_free_list;
+
+    while (ptr)
+    {
+        if (ptr->length >= size)
+        {
+            return ptr;
+        }
+        ptr = ptr->next;
+    }
+
+    return NULL;
+}
+
+/**
+ * @brief 扩容malloc管理的内存区域
+ *
+ * @param size 扩大的内存大小
+ */
+static int malloc_enlarge(int64_t size)
+{
+    if (brk_base_addr == 0) // 第一次调用，需要初始化
+    {
+        brk_base_addr = sbrk(0);
+        // printf("brk_base_addr=%#018lx\n", brk_base_addr);
+        brk_managed_addr = brk_base_addr;
+        brk_max_addr = sbrk(0);
+    }
+
+    int64_t free_space = brk_max_addr - brk_managed_addr;
+    // printf("size=%ld\tfree_space=%ld\n", size, free_space);
+    if (free_space < size) // 现有堆空间不足
+    {
+        if (sbrk(size - free_space) != (void *)(-1))
+            brk_max_addr = sbrk((0));
+        else
+        {
+            //put_string("malloc_enlarge(): no_mem\n", COLOR_YELLOW, COLOR_BLACK);
+            return -ENOMEM;
+        }
+
+        // printf("brk max addr = %#018lx\n", brk_max_addr);
+    }
+
+    // 扩展管理的堆空间
+    // 在新分配的内存的底部放置header
+    // printf("managed addr = %#018lx\n", brk_managed_addr);
+    malloc_mem_chunk_t *new_ck = (malloc_mem_chunk_t *)brk_managed_addr;
+    new_ck->length = brk_max_addr - brk_managed_addr;
+    // printf("new_ck->start_addr=%#018lx\tbrk_max_addr=%#018lx\tbrk_managed_addr=%#018lx\n", (uint64_t)new_ck, brk_max_addr, brk_managed_addr);
+    new_ck->prev = NULL;
+    new_ck->next = NULL;
+    brk_managed_addr = brk_max_addr;
+
+    malloc_insert_free_list(new_ck);
+
+    return 0;
+}
+
+/**
+ * @brief 合并空闲块
+ *
+ */
+static void malloc_merge_free_chunk()
+{
+    if (malloc_free_list == NULL)
+        return;
+    malloc_mem_chunk_t *ptr = malloc_free_list->next;
+    while (ptr != NULL)
+    {
+        // 内存块连续
+        if (((uint64_t)(ptr->prev) + ptr->prev->length == (uint64_t)ptr))
+        {
+            // printf("merged %#018lx  and %#018lx\n", (uint64_t)ptr, (uint64_t)(ptr->prev));
+            // 将ptr与前面的空闲块合并
+            ptr->prev->length += ptr->length;
+            ptr->prev->next = ptr->next;
+            if (ptr->next == NULL)
+                malloc_free_list_end = ptr->prev;
+            else
+                ptr->next->prev = ptr->prev;
+            // 由于内存组成结构的原因，不需要free掉header
+            ptr = ptr->prev;
+        }
+        ptr = ptr->next;
+    }
+}
+
+/**
+ * @brief 将块插入空闲链表
+ *
+ * @param ck 待插入的块
+ */
+static void malloc_insert_free_list(malloc_mem_chunk_t *ck)
+{
+    if (malloc_free_list == NULL) // 空闲链表为空
+    {
+        malloc_free_list = ck;
+        malloc_free_list_end = ck;
+        ck->prev = ck->next = NULL;
+        return;
+    }
+    else
+    {
+
+        malloc_mem_chunk_t *ptr = malloc_free_list;
+        while (ptr != NULL)
+        {
+            if ((uint64_t)ptr < (uint64_t)ck)
+            {
+                if (ptr->next == NULL) // 当前是最后一个项
+                {
+                    ptr->next = ck;
+                    ck->next = NULL;
+                    ck->prev = ptr;
+                    malloc_free_list_end = ck;
+                    break;
+                }
+                else if ((uint64_t)(ptr->next) > (uint64_t)ck)
+                {
+                    ck->prev = ptr;
+                    ck->next = ptr->next;
+                    ptr->next = ck;
+                    ck->next->prev = ck;
+                    break;
+                }
+            }
+            else // 在ptr之前插入
+            {
+
+                if (ptr->prev == NULL) // 是第一个项
+                {
+                    malloc_free_list = ck;
+                    ck->prev = NULL;
+                    ck->next = ptr;
+                    ptr->prev = ck;
+                    break;
+                }
+                else
+                {
+                    ck->prev = ptr->prev;
+                    ck->next = ptr;
+                    ck->prev->next = ck;
+                    ptr->prev = ck;
+                    break;
+                }
+            }
+            ptr = ptr->next;
+        }
+    }
+}
+
+/**
+ * @brief 获取一块堆内存
+ *
+ * @param size 内存大小
+ * @return void* 内存空间的指针
+ *
+ * 分配内存的时候，结点的prev next指针所占用的空间被当做空闲空间分配出去
+ */
+void *_dragonos_malloc(ssize_t size)
+{
+    
+    // 计算需要分配的块的大小
+    // reserve for len
+    if (size + 2*sizeof(uint64_t) <= sizeof(malloc_mem_chunk_t))
+        size = sizeof(malloc_mem_chunk_t);
+    else
+        size += 2*sizeof(uint64_t);
+
+    // 采用best fit
+    malloc_mem_chunk_t *ck = malloc_query_free_chunk_bf(size);
+
+    if (ck == NULL) // 没有空闲块
+    {
+        
+        // printf("no free blocks\n");
+        // 尝试合并空闲块
+        malloc_merge_free_chunk();
+        ck = malloc_query_free_chunk_bf(size);
+
+        // 找到了合适的块
+        if (ck)
+            goto found;
+
+        // printf("before enlarge\n");
+        // 找不到合适的块，扩容堆区域
+        if (malloc_enlarge(size) == -ENOMEM)
+            return (void *)-ENOMEM; // 内存不足
+
+        malloc_merge_free_chunk(); // 扩容后运行合并，否则会导致碎片
+
+        // 扩容后再次尝试获取
+
+        ck = malloc_query_free_chunk_bf(size);
+    }
+found:;
+
+    // printf("ck = %#018lx\n", (uint64_t)ck);
+    if (ck == NULL)
+        return (void *)-ENOMEM;
+    // printf("ck->prev=%#018lx ck->next=%#018lx\n", ck->prev, ck->next);
+    // 分配空闲块
+    // 从空闲链表取出
+    if (ck->prev == NULL) // 当前是链表的第一个块
+    {
+        malloc_free_list = ck->next;
+    }
+    else
+        ck->prev->next = ck->next;
+
+    if (ck->next != NULL) // 当前不是最后一个块
+        ck->next->prev = ck->prev;
+    else
+        malloc_free_list_end = ck->prev;
+
+    // 当前块剩余的空间还能容纳多一个结点的空间，则分裂当前块
+    if ((int64_t)(ck->length) - size > sizeof(malloc_mem_chunk_t))
+    {
+        // printf("seperate\n");
+        malloc_mem_chunk_t *new_ck = (malloc_mem_chunk_t *)(((uint64_t)ck) + size);
+        new_ck->length = ck->length - size;
+        new_ck->prev = new_ck->next = NULL;
+        // printf("new_ck=%#018lx, new_ck->length=%#010lx\n", (uint64_t)new_ck, new_ck->length);
+        ck->length = size;
+        malloc_insert_free_list(new_ck);
+    }
+    // printf("malloc done: %#018lx, length=%#018lx\n", ((uint64_t)ck + sizeof(uint64_t)), ck->length);
+    // 此时链表结点的指针的空间被分配出去
+    return (void *)((uint64_t)ck + sizeof(uint64_t));
+}
+
+/**
+ * @brief 当堆顶空闲空间大于2个页的空间的时候，释放1个页
+ *
+ */
+static void release_brk()
+{
+    // 先检测最顶上的块
+    // 由于块按照开始地址排列，因此找最后一个块
+    if (malloc_free_list_end == NULL)
+    {
+        printf("release(): free list end is null. \n");
+        return;
+    }
+    if ((uint64_t)malloc_free_list_end + malloc_free_list_end->length == brk_max_addr && (uint64_t)malloc_free_list_end <= brk_max_addr - (PAGE_2M_SIZE << 1))
+    {
+        int64_t delta = ((brk_max_addr - (uint64_t)malloc_free_list_end) & PAGE_2M_MASK) - PAGE_2M_SIZE;
+        // printf("(brk_max_addr - (uint64_t)malloc_free_list_end) & PAGE_2M_MASK=%#018lx\n ", (brk_max_addr - (uint64_t)malloc_free_list_end) & PAGE_2M_MASK);
+        // printf("PAGE_2M_SIZE=%#018lx\n", PAGE_2M_SIZE);
+        // printf("tdfghgbdfggkmfn=%#018lx\n ", (brk_max_addr - (uint64_t)malloc_free_list_end) & PAGE_2M_MASK - PAGE_2M_SIZE);
+        // printf("delta=%#018lx\n ", delta);
+        if (delta <= 0) // 不用释放内存
+            return;
+        sbrk(-delta);
+        brk_max_addr = sbrk(0);
+        brk_managed_addr = brk_max_addr;
+
+        malloc_free_list_end->length = brk_max_addr - (uint64_t)malloc_free_list_end;
+    }
+}
+/**
+ * @brief 释放一块堆内存
+ *
+ * @param ptr 堆内存的指针
+ */
+void _dragonos_free(void *ptr)
+{
+    // 找到结点（此时prev和next都处于未初始化的状态）
+    malloc_mem_chunk_t *ck = (malloc_mem_chunk_t *)((uint64_t)ptr - sizeof(uint64_t));
+    // printf("free(): addr = %#018lx\t len=%#018lx\n", (uint64_t)ck, ck->length);
+    count_last_free_size += ck->length;
+
+    malloc_insert_free_list(ck);
+
+    if (count_last_free_size > PAGE_2M_SIZE)
+    {
+        count_last_free_size = 0;
+        malloc_merge_free_chunk();
+        release_brk();
+    }
+}