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调整user下libs的libc目录结构 (#103)
* 调整user下libs的libc目录结构 * 修正.gitignore文件的问题 * 修复无法编译的问题 Co-authored-by: longjin <longjin@RinGoTek.cn>
This commit is contained in:
wwc-15172310230
GitHub
.gitignore
.vscode
docs/userland/libc/apis
user
Makefile
apps
libs
Makefile
libKeyboard
libc
.cargo
.gitignoreCargo.tomlMakefilesrc
libsystem
392
user/libs/libc/src/malloc.c
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392
user/libs/libc/src/malloc.c
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@ -0,0 +1,392 @@
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#include <libc/src/stdlib.h>
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#include <libsystem/syscall.h>
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#include <libc/src/stddef.h>
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#include <libc/src/unistd.h>
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#include <libc/src/errno.h>
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#include <libc/src/stdio.h>
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#define PAGE_4K_SHIFT 12
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#define PAGE_2M_SHIFT 21
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#define PAGE_1G_SHIFT 30
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#define PAGE_GDT_SHIFT 39
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// 不同大小的页的容量
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#define PAGE_4K_SIZE (1UL << PAGE_4K_SHIFT)
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#define PAGE_2M_SIZE (1UL << PAGE_2M_SHIFT)
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#define PAGE_1G_SIZE (1UL << PAGE_1G_SHIFT)
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// 屏蔽低于x的数值
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#define PAGE_4K_MASK (~(PAGE_4K_SIZE - 1))
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#define PAGE_2M_MASK (~(PAGE_2M_SIZE - 1))
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// 将addr按照x的上边界对齐
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#define PAGE_4K_ALIGN(addr) (((unsigned long)(addr) + PAGE_4K_SIZE - 1) & PAGE_4K_MASK)
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#define PAGE_2M_ALIGN(addr) (((unsigned long)(addr) + PAGE_2M_SIZE - 1) & PAGE_2M_MASK)
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/**
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* @brief 显式链表的结点
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*
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*/
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typedef struct malloc_mem_chunk_t
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{
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uint64_t length; // 整个块所占用的内存区域的大小
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struct malloc_mem_chunk_t *prev; // 上一个结点的指针
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struct malloc_mem_chunk_t *next; // 下一个结点的指针
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} malloc_mem_chunk_t;
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static uint64_t brk_base_addr = 0; // 堆区域的内存基地址
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static uint64_t brk_max_addr = 0; // 堆区域的内存最大地址
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static uint64_t brk_managed_addr = 0; // 堆区域已经被管理的地址
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// 空闲链表
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// 按start_addr升序排序
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static malloc_mem_chunk_t *malloc_free_list = NULL;
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static malloc_mem_chunk_t *malloc_free_list_end = NULL; // 空闲链表的末尾结点
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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
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/**
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* @brief 将块插入空闲链表
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*
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* @param ck 待插入的块
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*/
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static void malloc_insert_free_list(malloc_mem_chunk_t *ck);
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/**
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* @brief 当堆顶空闲空间大于2个页的空间的时候，释放1个页
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*
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*/
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static void release_brk();
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/**
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* @brief 在链表中检索符合要求的空闲块（best fit）
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*
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* @param size 块的大小
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* @return malloc_mem_chunk_t*
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*/
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static malloc_mem_chunk_t *malloc_query_free_chunk_bf(uint64_t size)
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{
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// 在满足best fit的前提下，尽可能的使分配的内存在低地址
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// 使得总的堆内存可以更快被释放
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if (malloc_free_list == NULL)
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{
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return NULL;
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}
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malloc_mem_chunk_t *ptr = malloc_free_list;
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malloc_mem_chunk_t *best = NULL;
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// printf("query size=%d", size);
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while (ptr != NULL)
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{
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// printf("ptr->length=%#010lx\n", ptr->length);
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if (ptr->length == size)
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{
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best = ptr;
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break;
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}
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if (ptr->length > size)
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{
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if (best == NULL)
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best = ptr;
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else if (best->length > ptr->length)
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best = ptr;
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}
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ptr = ptr->next;
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}
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return best;
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}
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/**
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* @brief 在链表中检索符合要求的空闲块（first fit）
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*
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* @param size
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* @return malloc_mem_chunk_t*
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*/
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static malloc_mem_chunk_t *malloc_query_free_chunk_ff(uint64_t size)
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{
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if (malloc_free_list == NULL)
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return NULL;
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malloc_mem_chunk_t *ptr = malloc_free_list;
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while (ptr)
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{
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if (ptr->length >= size)
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{
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return ptr;
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}
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ptr = ptr->next;
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}
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return NULL;
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}
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/**
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* @brief 扩容malloc管理的内存区域
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*
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* @param size 扩大的内存大小
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*/
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static int malloc_enlarge(int64_t size)
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{
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if (brk_base_addr == 0) // 第一次调用，需要初始化
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{
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brk_base_addr = brk(-1);
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// printf("brk_base_addr=%#018lx\n", brk_base_addr);
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brk_managed_addr = brk_base_addr;
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brk_max_addr = brk(-2);
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}
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int64_t free_space = brk_max_addr - brk_managed_addr;
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// printf("size=%ld\tfree_space=%ld\n", size, free_space);
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if (free_space < size) // 现有堆空间不足
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{
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if (sbrk(size - free_space) != (void *)(-1))
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brk_max_addr = brk((-2));
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else
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{
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put_string("malloc_enlarge(): no_mem\n", COLOR_YELLOW, COLOR_BLACK);
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return -ENOMEM;
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}
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// printf("brk max addr = %#018lx\n", brk_max_addr);
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}
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// 扩展管理的堆空间
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// 在新分配的内存的底部放置header
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// printf("managed addr = %#018lx\n", brk_managed_addr);
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malloc_mem_chunk_t *new_ck = (malloc_mem_chunk_t *)brk_managed_addr;
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new_ck->length = brk_max_addr - brk_managed_addr;
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// 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);
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new_ck->prev = NULL;
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new_ck->next = NULL;
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brk_managed_addr = brk_max_addr;
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malloc_insert_free_list(new_ck);
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return 0;
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}
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/**
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* @brief 合并空闲块
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*
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*/
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static void malloc_merge_free_chunk()
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{
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if (malloc_free_list == NULL)
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return;
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malloc_mem_chunk_t *ptr = malloc_free_list->next;
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while (ptr != NULL)
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{
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// 内存块连续
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if (((uint64_t)(ptr->prev) + ptr->prev->length == (uint64_t)ptr))
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{
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// printf("merged %#018lx and %#018lx\n", (uint64_t)ptr, (uint64_t)(ptr->prev));
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// 将ptr与前面的空闲块合并
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ptr->prev->length += ptr->length;
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ptr->prev->next = ptr->next;
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if (ptr->next == NULL)
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malloc_free_list_end = ptr->prev;
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else
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ptr->next->prev = ptr->prev;
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// 由于内存组成结构的原因，不需要free掉header
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ptr = ptr->prev;
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}
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ptr = ptr->next;
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}
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}
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/**
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* @brief 将块插入空闲链表
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*
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* @param ck 待插入的块
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*/
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static void malloc_insert_free_list(malloc_mem_chunk_t *ck)
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{
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if (malloc_free_list == NULL) // 空闲链表为空
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{
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malloc_free_list = ck;
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malloc_free_list_end = ck;
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ck->prev = ck->next = NULL;
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return;
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}
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else
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{
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malloc_mem_chunk_t *ptr = malloc_free_list;
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while (ptr != NULL)
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{
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if ((uint64_t)ptr < (uint64_t)ck)
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{
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if (ptr->next == NULL) // 当前是最后一个项
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{
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ptr->next = ck;
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ck->next = NULL;
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ck->prev = ptr;
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malloc_free_list_end = ck;
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break;
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}
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else if ((uint64_t)(ptr->next) > (uint64_t)ck)
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{
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ck->prev = ptr;
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ck->next = ptr->next;
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ptr->next = ck;
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ck->next->prev = ck;
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break;
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}
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}
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else // 在ptr之前插入
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{
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if (ptr->prev == NULL) // 是第一个项
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{
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malloc_free_list = ck;
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ck->prev = NULL;
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ck->next = ptr;
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ptr->prev = ck;
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break;
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}
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else
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{
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ck->prev = ptr->prev;
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ck->next = ptr;
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ck->prev->next = ck;
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ptr->prev = ck;
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break;
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}
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}
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ptr = ptr->next;
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}
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}
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}
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/**
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* @brief 获取一块堆内存
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*
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* @param size 内存大小
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* @return void* 内存空间的指针
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*
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* 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
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*/
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void *malloc(ssize_t size)
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{
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// printf("malloc\n");
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// 计算需要分配的块的大小
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if (size + sizeof(uint64_t) <= sizeof(malloc_mem_chunk_t))
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size = sizeof(malloc_mem_chunk_t);
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else
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size += sizeof(uint64_t);
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// 采用best fit
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malloc_mem_chunk_t *ck = malloc_query_free_chunk_bf(size);
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if (ck == NULL) // 没有空闲块
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{
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// printf("no free blocks\n");
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// 尝试合并空闲块
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malloc_merge_free_chunk();
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ck = malloc_query_free_chunk_bf(size);
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// 找到了合适的块
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if (ck)
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goto found;
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// printf("before enlarge\n");
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// 找不到合适的块，扩容堆区域
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if (malloc_enlarge(size) == -ENOMEM)
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return (void *)-ENOMEM; // 内存不足
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malloc_merge_free_chunk(); // 扩容后运行合并，否则会导致碎片
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// 扩容后再次尝试获取
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ck = malloc_query_free_chunk_bf(size);
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}
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found:;
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// printf("ck = %#018lx\n", (uint64_t)ck);
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if (ck == NULL)
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return (void *)-ENOMEM;
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// printf("ck->prev=%#018lx ck->next=%#018lx\n", ck->prev, ck->next);
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// 分配空闲块
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// 从空闲链表取出
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if (ck->prev == NULL) // 当前是链表的第一个块
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{
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malloc_free_list = ck->next;
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}
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else
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ck->prev->next = ck->next;
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if (ck->next != NULL) // 当前不是最后一个块
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ck->next->prev = ck->prev;
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else
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malloc_free_list_end = ck->prev;
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// 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
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if ((int64_t)(ck->length) - size > sizeof(malloc_mem_chunk_t))
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{
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// printf("seperate\n");
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malloc_mem_chunk_t *new_ck = (malloc_mem_chunk_t *)(((uint64_t)ck) + size);
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new_ck->length = ck->length - size;
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new_ck->prev = new_ck->next = NULL;
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// printf("new_ck=%#018lx, new_ck->length=%#010lx\n", (uint64_t)new_ck, new_ck->length);
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ck->length = size;
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malloc_insert_free_list(new_ck);
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}
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// printf("malloc done: %#018lx, length=%#018lx\n", ((uint64_t)ck + sizeof(uint64_t)), ck->length);
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// 此时链表结点的指针的空间被分配出去
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return (void *)((uint64_t)ck + sizeof(uint64_t));
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}
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/**
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* @brief 当堆顶空闲空间大于2个页的空间的时候，释放1个页
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*
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*/
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static void release_brk()
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{
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// 先检测最顶上的块
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// 由于块按照开始地址排列，因此找最后一个块
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if (malloc_free_list_end == NULL)
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{
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printf("release(): free list end is null. \n");
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return;
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}
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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))
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{
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int64_t delta = ((brk_max_addr - (uint64_t)malloc_free_list_end) & PAGE_2M_MASK) - PAGE_2M_SIZE;
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// 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);
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// printf("PAGE_2M_SIZE=%#018lx\n", PAGE_2M_SIZE);
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// printf("tdfghgbdfggkmfn=%#018lx\n ", (brk_max_addr - (uint64_t)malloc_free_list_end) & PAGE_2M_MASK - PAGE_2M_SIZE);
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// printf("delta=%#018lx\n ", delta);
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if (delta <= 0) // 不用释放内存
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return;
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sbrk(-delta);
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brk_max_addr = brk(-2);
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brk_managed_addr = brk_max_addr;
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malloc_free_list_end->length = brk_max_addr - (uint64_t)malloc_free_list_end;
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}
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}
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/**
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* @brief 释放一块堆内存
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*
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* @param ptr 堆内存的指针
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*/
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void free(void *ptr)
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{
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// 找到结点（此时prev和next都处于未初始化的状态）
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malloc_mem_chunk_t *ck = (malloc_mem_chunk_t *)((uint64_t)ptr - sizeof(uint64_t));
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// printf("free(): addr = %#018lx\t len=%#018lx\n", (uint64_t)ck, ck->length);
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count_last_free_size += ck->length;
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malloc_insert_free_list(ck);
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if (count_last_free_size > PAGE_2M_SIZE)
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{
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count_last_free_size = 0;
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malloc_merge_free_chunk();
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release_brk();
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}
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}
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