From 828621dbbc8dd943a01a1d8e273aaa15616bba27 Mon Sep 17 00:00:00 2001 From: fslongjin Date: Fri, 25 Feb 2022 20:01:08 +0800 Subject: [PATCH] :new: kmalloc --- kernel/mm/mm.c | 2 +- kernel/mm/slab.c | 193 +++++++++++++++++++++++++++++++++++++++++++---- kernel/mm/slab.h | 9 +++ 3 files changed, 189 insertions(+), 15 deletions(-) diff --git a/kernel/mm/mm.c b/kernel/mm/mm.c index 7fad2806..9b7c2503 100644 --- a/kernel/mm/mm.c +++ b/kernel/mm/mm.c @@ -68,7 +68,7 @@ void mm_init() memory_management_struct.bmp_len = (((unsigned long)(max_addr >> PAGE_2M_SHIFT) + sizeof(unsigned long) * 8 - 1) / 8) & (~(sizeof(unsigned long) - 1)); // bmp由多少个unsigned long变量组成 // 初始化bitmap， 先将整个bmp空间全部置位。稍后再将可用物理内存页复位。 - memset(memory_management_struct.bmp, 0xffffffffffffffff, memory_management_struct.bmp_len); + memset(memory_management_struct.bmp, 0xff, memory_management_struct.bmp_len); // 初始化内存页结构 // 将页结构映射于bmp之后 diff --git a/kernel/mm/slab.c b/kernel/mm/slab.c index 2976f131..2eeed39a 100644 --- a/kernel/mm/slab.c +++ b/kernel/mm/slab.c @@ -348,19 +348,13 @@ ul slab_init() // bmp后方预留4个unsigned long的空间防止内存越界,且按照8byte进行对齐 memory_management_struct.end_of_struct += kmalloc_cache_group[i].cache_pool->bmp_len + ((sizeof(ul) << 2) & (~sizeof(ul) - 1)); - memset(kmalloc_cache_group[i].cache_pool->bmp, 0, kmalloc_cache_group[i].cache_pool->bmp_len); + // @todo：此处可优化，直接把所有位设置为0，然后再对部分不存在对应的内存对象的位设置为1 + memset(kmalloc_cache_group[i].cache_pool->bmp, 0xff, kmalloc_cache_group[i].cache_pool->bmp_len); + for (int j = 0; j < kmalloc_cache_group[i].cache_pool->bmp_count; ++j) + *(kmalloc_cache_group[i].cache_pool->bmp + (j >> 6)) ^= 1UL << (j % 64); kmalloc_cache_group[i].count_total_using = 0; kmalloc_cache_group[i].count_total_free = kmalloc_cache_group[i].cache_pool->count_free; - /* - memset(kmalloc_cache_size[i].cache_pool->color_map,0xff,kmalloc_cache_size[i].cache_pool->color_length); - - for(j = 0;j < kmalloc_cache_size[i].cache_pool->color_count;j++) - *(kmalloc_cache_size[i].cache_pool->color_map + (j >> 6)) ^= 1UL << j % 64; - - kmalloc_cache_size[i].total_free = kmalloc_cache_size[i].cache_pool->color_count; - kmalloc_cache_size[i].total_using = 0; - */ } struct Page *page = NULL; @@ -388,10 +382,10 @@ ul slab_init() for (int i = 0; i < 16; ++i) { // 获取一个新的空页并添加到空页表，然后返回其虚拟地址 - virt = (ul*)(PAGE_2M_ALIGN(memory_management_struct.end_of_struct+PAGE_2M_SIZE*i)); + virt = (ul *)(PAGE_2M_ALIGN(memory_management_struct.end_of_struct + PAGE_2M_SIZE * i)); page = Virt_To_2M_Page(virt); - page_init(page, PAGE_PGT_MAPPED|PAGE_KERNEL|PAGE_KERNEL_INIT); + page_init(page, PAGE_PGT_MAPPED | PAGE_KERNEL | PAGE_KERNEL_INIT); kmalloc_cache_group[i].cache_pool->page = page; kmalloc_cache_group[i].cache_pool->vaddr = virt; @@ -401,16 +395,187 @@ ul slab_init() return 0; } +/** + * @brief 在kmalloc中创建slab_obj的函数（与slab_malloc()中的类似) + * + * @param size + * @return struct slab_obj* 创建好的slab_obj + */ + +struct slab_obj *kmalloc_create_slab_obj(ul size) +{ + struct Page *page = alloc_pages(ZONE_NORMAL, 1, 0); + + // BUG + if (page == NULL) + { + kBUG("kmalloc_create()->alloc_pages()=>page == NULL"); + return NULL; + } + + page_init(page, PAGE_KERNEL); + + ul *vaddr = NULL; + ul struct_size = 0; + struct slab_obj *slab_obj_ptr; + + // 根据size大小，选择不同的分支来处理 + // 之所以选择512byte为分界点，是因为，此时bmp大小刚好为512byte。显而易见，选择过小的话会导致kmalloc函数与当前函数反复互相调用，最终导致栈溢出 + switch (size) + { + // ============ 对于size<=512byte的内存池对象，将slab_obj结构体和bmp放置在物理页的内部 ======== + // 由于这些对象的特征是，bmp占的空间大，而内存块的空间小，这样做的目的是避免再去申请一块内存来存储bmp，减少浪费。 + case 32: + case 64: + case 128: + case 256: + case 512: + vaddr = phys_2_virt(page->addr_phys); + // slab_obj结构体的大小 （本身的大小+bmp的大小） + struct_size = sizeof(struct slab_obj) + PAGE_2M_SIZE / size / 8; + // 将slab_obj放置到物理页的末尾 + slab_obj_ptr = (struct slab_obj *)((unsigned char *)vaddr + PAGE_2M_SIZE - struct_size); + slab_obj_ptr->bmp = (ul *)slab_obj_ptr + sizeof(struct slab_obj); + + slab_obj_ptr->count_free = (PAGE_2M_SIZE - struct_size) / size; + slab_obj_ptr->count_using = 0; + slab_obj_ptr->bmp_count = slab_obj_ptr->count_free; + slab_obj_ptr->vaddr = vaddr; + slab_obj_ptr->page = page; + + list_init(&slab_obj_ptr->list); + + slab_obj_ptr->bmp_len = ((slab_obj_ptr->bmp_count + sizeof(ul) * 8 - 1) >> 6) << 3; + + // @todo：此处可优化，直接把所有位设置为0，然后再对部分不存在对应的内存对象的位设置为1 + memset(slab_obj_ptr->bmp, 0xff, slab_obj_ptr->bmp_len); + + for (int i = 0; i < slab_obj_ptr->bmp_count; ++i) + *(slab_obj_ptr->bmp + (i >> 6)) ^= 1UL << (i % 64); + + break; + // ================= 较大的size时，slab_obj和bmp不再放置于当前物理页内部 ============ + // 因为在这种情况下，bmp很短，继续放置在当前物理页内部则会造成可分配的对象少，加剧了内存空间的浪费 + case 1024: // 1KB + case 2048: + case 4096: // 4KB + case 8192: + case 16384: + case 32768: + case 65536: + case 131072: // 128KB + case 262144: + case 524288: + case 1048576: // 1MB + slab_obj_ptr = (struct Slab *)kmalloc(sizeof(struct slab_obj), 0); + + slab_obj_ptr->count_free = PAGE_2M_SIZE / size; + slab_obj_ptr->count_using = 0; + slab_obj_ptr->bmp_count = slab_obj_ptr->count_free; + + slab_obj_ptr->bmp_len = ((slab_obj_ptr->bmp_count + sizeof(ul) * 8 - 1) >> 6) << 3; + + slab_obj_ptr->bmp = (ul *)kmalloc(slab_obj_ptr->bmp_len, 0); + + // @todo：此处可优化，直接把所有位设置为0，然后再对部分不存在对应的内存对象的位设置为1 + memset(slab_obj_ptr->bmp, 0xff, slab_obj_ptr->bmp_len); + for (int i = 0; i < slab_obj_ptr->bmp_count; ++i) + *(slab_obj_ptr->bmp + (i >> 6)) ^= 1UL << (i % 64); + + slab_obj_ptr->vaddr = phys_2_virt(page->addr_phys); + slab_obj_ptr->page = page; + list_init(&slab_obj_ptr->list); + break; + // size 错误 + default: + kerror("kamlloc_create(): Wrong size%d\n", size); + free_pages(page, 1); + return NULL; + break; + } + + return slab_obj_ptr; +} + /** * @brief 通用内存分配函数 * * @param size 要分配的内存大小 * @param flags 内存的flag - * @return void* + * @return void* 内核内存虚拟地址 */ void *kmalloc(unsigned long size, unsigned long flags) { - // @todo: 内存分配函数 + if (size > 1048576) + { + kwarn("kmalloc(): Can't alloc such memory: %ld bytes, because it is too large.", size); + return NULL; + } + int index; + for (int i = 0; i < 16; ++i) + if (kmalloc_cache_group[i].size >= size) + { + index = i; + break; + } + + struct slab_obj *slab_obj_ptr = kmalloc_cache_group[index].cache_pool; + + // 内存池没有可用的内存对象，需要进行扩容 + if (kmalloc_cache_group[index].count_total_free == 0) + { + // 创建slab_obj + slab_obj_ptr = kmalloc_create_slab_obj(kmalloc_cache_group[index].size); + + // BUG + if (slab_obj_ptr == NULL) + { + kBUG("kmalloc()->kmalloc_create_slab_obj()=>slab == NULL"); + return NULL; + } + + kmalloc_cache_group[index].count_total_free += slab_obj_ptr->count_free; + list_add(&kmalloc_cache_group[index].cache_pool->list, &slab_obj_ptr->list); + } + else // 内存对象充足 + { + do + { + // 跳转到下一个内存池对象 + if (slab_obj_ptr->count_free == 0) + slab_obj_ptr = container_of(list_next(&slab_obj_ptr->list), struct slab_obj, list); + else + break; + } while (slab_obj_ptr != kmalloc_cache_group[index].cache_pool); + } + + // 寻找一块可用的内存对象 + int md; + for (int i = 0; i < slab_obj_ptr->count_free; ++i) + { + // 当前bmp全部被使用 + if (*slab_obj_ptr->bmp + (i >> 6) == 0xffffffffffffffffUL) + { + i += 63; + continue; + } + md = i % 64; + // 找到相应的内存对象 + if (*(slab_obj_ptr->bmp + (i >> 6)) & (1UL << md) == 0) + { + *(slab_obj_ptr->bmp + (i >> 6)) |= (1UL << md); + ++(slab_obj_ptr->count_using); + --(slab_obj_ptr->count_free); + + --kmalloc_cache_group[index].count_total_free; + ++kmalloc_cache_group[index].count_total_using; + + return (void*)((char*)slab_obj_ptr->vaddr+kmalloc_cache_group[index].size*i); + } + } + + kerror("kmalloc(): Cannot alloc more memory: %d bytes", size); + return NULL; } /** diff --git a/kernel/mm/slab.h b/kernel/mm/slab.h index 1328aaf0..67ff3ffe 100644 --- a/kernel/mm/slab.h +++ b/kernel/mm/slab.h @@ -102,6 +102,15 @@ void *slab_malloc(struct slab *slab_pool, ul arg); */ ul slab_free(struct slab *slab_pool, void *addr, ul arg); +/** + * @brief 在kmalloc中创建slab_obj的函数（与slab_malloc()类似) + * + * @param size + * @return struct slab_obj* 创建好的slab_obj + */ +struct slab_obj * kmalloc_create_slab_obj(ul size); + + /** * @brief 初始化内存池组 * 在初始化通用内存管理单元期间，尚无内存空间分配函数，需要我们手动为SLAB内存池指定存储空间