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注解 动态内存池分成了哪三部分来管理? 代码实现有哪些亮点值得点赞 ? 

搜索 @note_pic 方便理解画的字符图
搜索 @note_why 尚未看明白的地方，如果您看明白了，请告知完善
搜索 @note_thinking 一点思考和吐槽的地方
搜索 @note_#if0 由第三方项目提供不由内核源码中定义的极为重要的结构体，为方便理解而添加的
搜索 @note_good 给源码点赞
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kernel/base/include/los_multipledlinkhead_pri.h
浏览文件 @ b553c5fc
/*
* Copyright (c) 2013-2019, Huawei Technologies Co., Ltd. All rights reserved.
* Copyright (c) 2020, Huawei Device Co., Ltd. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this list of
* conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice, this list
* of conditions and the following disclaimer in the documentation and/or other materials
* provided with the distribution.
*
* 3. Neither the name of the copyright holder nor the names of its contributors may be used
* to endorse or promote products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef _LOS_MULTIPLE_DLINK_HEAD_PRI_H
#define _LOS_MULTIPLE_DLINK_HEAD_PRI_H
#include "los_base.h"
#include "los_list.h"
#ifdef __cplusplus
#if __cplusplus
extern "C" {
#endif /* __cplusplus */
#endif /* __cplusplus */
#define OS_MAX_MULTI_DLNK_LOG2 30
#define OS_MIN_MULTI_DLNK_LOG2 4
#define OS_MULTI_DLNK_NUM ((OS_MAX_MULTI_DLNK_LOG2 - OS_MIN_MULTI_DLNK_LOG2) + 1)
#define OS_DLNK_HEAD_SIZE OS_MULTI_DLNK_HEAD_SIZE
#define OS_MULTI_DLNK_HEAD_SIZE sizeof(LosMultipleDlinkHead)
typedef struct {
LOS_DL_LIST listHead[OS_MULTI_DLNK_NUM];
} LosMultipleDlinkHead;
STATIC INLINE LOS_DL_LIST *OsDLnkNextMultiHead(VOID *headAddr, LOS_DL_LIST *listNodeHead)
{
LosMultipleDlinkHead *head = (LosMultipleDlinkHead *)headAddr;
return (&head->listHead[OS_MULTI_DLNK_NUM - 1] == listNodeHead) ? NULL : (listNodeHead + 1);
}
extern VOID OsDLnkInitMultiHead(VOID *headAddr);
extern LOS_DL_LIST *OsDLnkMultiHead(VOID *headAddr, UINT32 size);
#ifdef __cplusplus
#if __cplusplus
}
#endif /* __cplusplus */
#endif /* __cplusplus */
#endif /* _LOS_MULTIPLE_DLINK_HEAD_PRI_H */
/*
* Copyright (c) 2013-2019, Huawei Technologies Co., Ltd. All rights reserved.
* Copyright (c) 2020, Huawei Device Co., Ltd. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this list of
* conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice, this list
* of conditions and the following disclaimer in the documentation and/or other materials
* provided with the distribution.
*
* 3. Neither the name of the copyright holder nor the names of its contributors may be used
* to endorse or promote products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef _LOS_MULTIPLE_DLINK_HEAD_PRI_H
#define _LOS_MULTIPLE_DLINK_HEAD_PRI_H
#include "los_base.h"
#include "los_list.h"
#ifdef __cplusplus
#if __cplusplus
extern "C" {
#endif /* __cplusplus */
#endif /* __cplusplus */
#define OS_MAX_MULTI_DLNK_LOG2 30 //最大分配内存大小 2^30 = 1G ,LOG2指的是对数的意思
#define OS_MIN_MULTI_DLNK_LOG2 4 //最小分配内存大小 2^4 = 16字节,LOG2指的是对数的意思 例如: log2 16 = 4
#define OS_MULTI_DLNK_NUM ((OS_MAX_MULTI_DLNK_LOG2 - OS_MIN_MULTI_DLNK_LOG2) + 1)//双向链表数组大小,[4,30],所以必须加1
#define OS_DLNK_HEAD_SIZE OS_MULTI_DLNK_HEAD_SIZE
#define OS_MULTI_DLNK_HEAD_SIZE sizeof(LosMultipleDlinkHead)
//每个元素是一个双向链表，所有free节点的控制头都会被分类挂在这个数组的双向链表中
typedef struct {//bestfit动态内存管理 第二部分
LOS_DL_LIST listHead[OS_MULTI_DLNK_NUM];
} LosMultipleDlinkHead;
//返回内存池中,参数链表头节点的下一个链表头节点位置
STATIC INLINE LOS_DL_LIST *OsDLnkNextMultiHead(VOID *headAddr, LOS_DL_LIST *listNodeHead)
{
LosMultipleDlinkHead *head = (LosMultipleDlinkHead *)headAddr;
//如果是最后一个了,返回NULL,表示没有下一个了.
return (&head->listHead[OS_MULTI_DLNK_NUM - 1] == listNodeHead) ? NULL : (listNodeHead + 1);
}
extern VOID OsDLnkInitMultiHead(VOID *headAddr);
extern LOS_DL_LIST *OsDLnkMultiHead(VOID *headAddr, UINT32 size);
#ifdef __cplusplus
#if __cplusplus
}
#endif /* __cplusplus */
#endif /* __cplusplus */
#endif /* _LOS_MULTIPLE_DLINK_HEAD_PRI_H */
kernel/base/mem/bestfit/los_memory.c
浏览文件 @ b553c5fc
......@@ -114,8 +114,8 @@ extern "C" {
#define MEM_POOL_EXPAND_DISABLE 0 //内存池禁止扩展
/* Memory pool information structure */
typedef struct {
VOID *pool; /* Starting address of a memory pool */ //内存池开始地址
typedef struct { //内存池信息结构体,bestfit动态内存管理第一部分
VOID *pool; /* Starting address of a memory pool */ //内存池开始地址,必须放在结构体首位
UINT32 poolSize; /* Memory pool size */ //内存池大小
UINT32 flag; /* Whether the memory pool supports expansion */ //内存池是否支持扩展
#if defined(OS_MEM_WATERLINE) && (OS_MEM_WATERLINE == YES) //警戒线
......@@ -128,9 +128,9 @@ typedef struct {
} LosMemPoolInfo;
/* Memory linked list control node structure */
typedef struct {
LOS_DL_LIST freeNodeInfo; /* Free memory node */
struct tagLosMemDynNode *preNode; /* Pointer to the previous memory node */
typedef struct {//内存链表节点实体结构体体
LOS_DL_LIST freeNodeInfo; /* Free memory node */ //空闲链表,将通过它挂到 LosMultipleDlinkHead[n]上
struct tagLosMemDynNode *preNode; /* Pointer to the previous memory node */ //指向前一个节点
#ifdef LOSCFG_MEM_HEAD_BACKUP
UINT32 gapSize;
......@@ -152,11 +152,11 @@ typedef struct {
UINT32 reserve2; /* 64-bit alignment */
#endif
/* Size and flag of the current node (the high two bits represent a flag,and the rest bits specify the size) */
UINT32 sizeAndFlag;
UINT32 sizeAndFlag;//当前节点的大小和标志（高两位表示标志，其余位指定大小）
} LosMemCtlNode;
/* Memory linked list node structure */
typedef struct tagLosMemDynNode {
typedef struct tagLosMemDynNode {//内存链表节点结构体,bestfit动态内存管理第三部分
#ifdef LOSCFG_MEM_HEAD_BACKUP
LosMemCtlNode backupNode;
#endif
......@@ -217,7 +217,7 @@ STATIC VOID OsMemNodeSave(LosMemDynNode *node);
#endif
#define OS_MEM_ALIGN(p, alignSize) (((UINTPTR)(p) + (alignSize) - 1) & ~((UINTPTR)((alignSize) - 1)))
#define OS_MEM_NODE_HEAD_SIZE sizeof(LosMemDynNode)
#define OS_MEM_NODE_HEAD_SIZE sizeof(LosMemDynNode) //内存池第三部分 一个节点的大小
#define OS_MEM_MIN_POOL_SIZE (OS_DLNK_HEAD_SIZE + (2 * OS_MEM_NODE_HEAD_SIZE) + sizeof(LosMemPoolInfo))
#define IS_POW_TWO(value) ((((UINTPTR)(value)) & ((UINTPTR)(value) - 1)) == 0)
#define POOL_ADDR_ALIGNSIZE 64
......@@ -243,27 +243,27 @@ STATIC VOID OsMemNodeSave(LosMemDynNode *node);
#define OS_MEM_NODE_GET_SIZE(sizeAndFlag) \
((sizeAndFlag) & ~OS_MEM_NODE_ALIGNED_AND_USED_FLAG)
#define OS_MEM_HEAD(pool, size) \
OsDLnkMultiHead(OS_MEM_HEAD_ADDR(pool), size)
OsDLnkMultiHead(OS_MEM_HEAD_ADDR(pool), size) //通过size找到链表头节点
#define OS_MEM_HEAD_ADDR(pool) \
((VOID *)((UINTPTR)(pool) + sizeof(LosMemPoolInfo)))
((VOID *)((UINTPTR)(pool) + sizeof(LosMemPoolInfo))) //指向内存池的第二部分
#define OS_MEM_NEXT_NODE(node) \
((LosMemDynNode *)(VOID *)((UINT8 *)(node) + OS_MEM_NODE_GET_SIZE((node)->selfNode.sizeAndFlag)))
((LosMemDynNode *)(VOID *)((UINT8 *)(node) + OS_MEM_NODE_GET_SIZE((node)->selfNode.sizeAndFlag)))//获取节点的下一个节点
#define OS_MEM_FIRST_NODE(pool) \
((LosMemDynNode *)(VOID *)((UINT8 *)OS_MEM_HEAD_ADDR(pool) + OS_DLNK_HEAD_SIZE))
((LosMemDynNode *)(VOID *)((UINT8 *)OS_MEM_HEAD_ADDR(pool) + OS_DLNK_HEAD_SIZE)) //指向内存池的第三部分
#define OS_MEM_END_NODE(pool, size) \
((LosMemDynNode *)(VOID *)(((UINT8 *)(pool) + (size)) - OS_MEM_NODE_HEAD_SIZE))
((LosMemDynNode *)(VOID *)(((UINT8 *)(pool) + (size)) - OS_MEM_NODE_HEAD_SIZE)) //指向内存池的第三部分的最后一个节点
#define OS_MEM_MIDDLE_ADDR_OPEN_END(startAddr, middleAddr, endAddr) \
(((UINT8 *)(startAddr) <= (UINT8 *)(middleAddr)) && ((UINT8 *)(middleAddr) < (UINT8 *)(endAddr)))
#define OS_MEM_MIDDLE_ADDR(startAddr, middleAddr, endAddr) \
(((UINT8 *)(startAddr) <= (UINT8 *)(middleAddr)) && ((UINT8 *)(middleAddr) <= (UINT8 *)(endAddr)))
#define OS_MEM_SET_MAGIC(value) \
(value) = (LOS_DL_LIST *)(((UINTPTR)&(value)) ^ (UINTPTR)(-1))
(value) = (LOS_DL_LIST *)(((UINTPTR)&(value)) ^ (UINTPTR)(-1)) //设置魔法数字
#define OS_MEM_MAGIC_VALID(value) \
(((UINTPTR)(value) ^ ((UINTPTR)&(value))) == (UINTPTR)(-1))
//变量前缀 uc:UINT8 us:UINT16 uw:UINT32 代表的意思
UINT8 *m_aucSysMem0 = NULL; //@note_why 不明白鸿蒙对虚拟内存分配为什么要用两个全局变量
UINT8 *m_aucSysMem1 = NULL; //auc是什么意思? 变量名最后0和1又代表什么意思? 就不能整个好听的名字吗？@note_thinking
(((UINTPTR)(value) ^ ((UINTPTR)&(value))) == (UINTPTR)(-1)) //魔法数字是否有效,被修改过即无效
//变量前缀 uc:UINT8 us:UINT16 uw:UINT32 的意思
//auc是什么意思? 为何要用0,1来命名,就不能整个好听的名字吗？@note_thinking
UINT8 *m_aucSysMem0 = NULL; //异常接管内存池
UINT8 *m_aucSysMem1 = NULL; //系统动态内存池
#ifdef LOSCFG_BASE_MEM_NODE_SIZE_CHECK
STATIC UINT8 g_memCheckLevel = LOS_MEM_CHECK_LEVEL_DEFAULT;
#endif
......@@ -613,7 +613,7 @@ STATIC INLINE VOID OsMemSetGapSize(LosMemCtlNode *ctlNode, UINT32 gapSize)
{
ctlNode->gapSize = gapSize;
}
//保存一个动态节点
STATIC VOID OsMemNodeSave(LosMemDynNode *node)
{
OsMemSetGapSize(&node->selfNode, 0);
......@@ -707,13 +707,13 @@ VOID LOS_MemBadNodeShow(VOID *pool)
}
#else /* without LOSCFG_MEM_HEAD_BACKUP */
//删除一个节点
STATIC VOID OsMemListDelete(LOS_DL_LIST *node, const VOID *firstNode)
{
(VOID)firstNode;
LOS_ListDelete(node);
}
//增加一个节点
STATIC VOID OsMemListAdd(LOS_DL_LIST *listNode, LOS_DL_LIST *node, const VOID *firstNode)
{
(VOID)firstNode;
......@@ -742,7 +742,7 @@ LITE_OS_SEC_TEXT_INIT UINT32 OsMemSystemInit(UINTPTR memStart)
m_aucSysMem1 = (UINT8 *)((memStart + (POOL_ADDR_ALIGNSIZE - 1)) & ~((UINTPTR)(POOL_ADDR_ALIGNSIZE - 1)));
poolSize = OS_SYS_MEM_SIZE;
ret = LOS_MemInit(m_aucSysMem1, poolSize);
ret = LOS_MemInit(m_aucSysMem1, poolSize);////初始化 m_aucSysMem1 内存池
PRINT_INFO("LiteOS system heap memory address:%p,size:0x%x\n", m_aucSysMem1, poolSize);
#ifndef LOSCFG_EXC_INTERACTION
m_aucSysMem0 = m_aucSysMem1;
......@@ -1843,18 +1843,18 @@ STATIC UINT32 OsMemPoolAdd(VOID *pool, UINT32 size)
return LOS_OK;
}
#endif
//内存池初始化
//初始化内存池
STATIC UINT32 OsMemInit(VOID *pool, UINT32 size)
{
LosMemPoolInfo *poolInfo = (LosMemPoolInfo *)pool;
LosMemPoolInfo *poolInfo = (LosMemPoolInfo *)pool;//内存池的头部信息
LosMemDynNode *newNode = NULL;
LosMemDynNode *endNode = NULL;
LOS_DL_LIST *listNodeHead = NULL;
poolInfo->pool = pool;
poolInfo->poolSize = size;
poolInfo->pool = pool; //内存池开始地址,这里决定了 pool 变量一定要放在结构体的首位
poolInfo->poolSize = size; //内存池大小
poolInfo->flag = MEM_POOL_EXPAND_DISABLE;//内存池默认不能扩展
OsDLnkInitMultiHead(OS_MEM_HEAD_ADDR(pool));
OsDLnkInitMultiHead(OS_MEM_HEAD_ADDR(pool));//初始化内存池的第二部分(双向链表部分)
newNode = OS_MEM_FIRST_NODE(pool);
newNode->selfNode.sizeAndFlag = (size - (UINT32)((UINTPTR)newNode - (UINTPTR)pool) - OS_MEM_NODE_HEAD_SIZE);
newNode->selfNode.preNode = (LosMemDynNode *)OS_MEM_END_NODE(pool, size);
......@@ -1881,7 +1881,13 @@ STATIC UINT32 OsMemInit(VOID *pool, UINT32 size)
return LOS_OK;
}
//初始化一块指定的动态内存池，大小为size
/******************************************************************************
初始化一块指定的动态内存池，大小为size,被以下函数调用
LiteIpcMmap
OsKHeapInit
OsMemSystemInit
OsMemExcInteractionInit
******************************************************************************/
LITE_OS_SEC_TEXT_INIT UINT32 LOS_MemInit(VOID *pool, UINT32 size)
{
UINT32 intSave;
......@@ -1904,7 +1910,7 @@ LITE_OS_SEC_TEXT_INIT UINT32 LOS_MemInit(VOID *pool, UINT32 size)
}
#endif
if (OsMemInit(pool, size)) {
if (OsMemInit(pool, size)) {//主体函数,初始化内存池
#ifdef LOSCFG_MEM_MUL_POOL
(VOID)LOS_MemDeInit(pool);
#endif
......@@ -3010,7 +3016,7 @@ STATUS_T OsKHeapInit(size_t size)
}
m_aucSysMem0 = m_aucSysMem1 = ptr;//内存池基地址，auc 是啥意思没整明白？
ret = LOS_MemInit(m_aucSysMem0, size);//初始化内存池
ret = LOS_MemInit(m_aucSysMem0, size);//初始化 m_aucSysMem0 内存池
if (ret != LOS_OK) {
PRINT_ERR("vmm_kheap_init LOS_MemInit failed!\n");
g_vmBootMemBase -= size;//分配失败时需归还size, g_vmBootMemBase是很野蛮粗暴的
......
kernel/base/mem/bestfit/los_multipledlinkhead.c
浏览文件 @ b553c5fc
/*
* Copyright (c) 2013-2019, Huawei Technologies Co., Ltd. All rights reserved.
* Copyright (c) 2020, Huawei Device Co., Ltd. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this list of
* conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice, this list
* of conditions and the following disclaimer in the documentation and/or other materials
* provided with the distribution.
*
* 3. Neither the name of the copyright holder nor the names of its contributors may be used
* to endorse or promote products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "los_multipledlinkhead_pri.h"
#include "los_bitmap.h"
#ifdef __cplusplus
#if __cplusplus
extern "C" {
#endif /* __cplusplus */
#endif /* __cplusplus */
STATIC INLINE UINT32 OsLog2(UINT32 size)
{
return (size > 0) ? (UINT32)LOS_HighBitGet(size) : 0;
}
//初始化内存池双循环链表 ，默认OS_MULTI_DLNK_NUM = 28个
LITE_OS_SEC_TEXT_INIT VOID OsDLnkInitMultiHead(VOID *headAddr)
{
LosMultipleDlinkHead *dlinkHead = (LosMultipleDlinkHead *)headAddr;
LOS_DL_LIST *listNodeHead = dlinkHead->listHead;
UINT32 index;
for (index = 0; index < OS_MULTI_DLNK_NUM; ++index, ++listNodeHead) {
LOS_ListInit(listNodeHead);
}
}
LITE_OS_SEC_TEXT_MINOR LOS_DL_LIST *OsDLnkMultiHead(VOID *headAddr, UINT32 size)
{
LosMultipleDlinkHead *dlinkHead = (LosMultipleDlinkHead *)headAddr;
UINT32 index = OsLog2(size);
if (index > OS_MAX_MULTI_DLNK_LOG2) {
return NULL;
} else if (index <= OS_MIN_MULTI_DLNK_LOG2) {
index = OS_MIN_MULTI_DLNK_LOG2;
}
return dlinkHead->listHead + (index - OS_MIN_MULTI_DLNK_LOG2);
}
#ifdef __cplusplus
#if __cplusplus
}
#endif /* __cplusplus */
#endif /* __cplusplus */
/*
* Copyright (c) 2013-2019, Huawei Technologies Co., Ltd. All rights reserved.
* Copyright (c) 2020, Huawei Device Co., Ltd. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this list of
* conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice, this list
* of conditions and the following disclaimer in the documentation and/or other materials
* provided with the distribution.
*
* 3. Neither the name of the copyright holder nor the names of its contributors may be used
* to endorse or promote products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "los_multipledlinkhead_pri.h"
#include "los_bitmap.h"
#ifdef __cplusplus
#if __cplusplus
extern "C" {
#endif /* __cplusplus */
#endif /* __cplusplus */
//获取size的最高位, 意思就是将size变成2^return 对数表示
STATIC INLINE UINT32 OsLog2(UINT32 size)
{
return (size > 0) ? (UINT32)LOS_HighBitGet(size) : 0;
}
//初始化内存池双向链表 ，默认OS_MULTI_DLNK_NUM = 27个
LITE_OS_SEC_TEXT_INIT VOID OsDLnkInitMultiHead(VOID *headAddr)
{
LosMultipleDlinkHead *dlinkHead = (LosMultipleDlinkHead *)headAddr;
LOS_DL_LIST *listNodeHead = dlinkHead->listHead;//拿到双向链表数组
UINT32 index;
for (index = 0; index < OS_MULTI_DLNK_NUM; ++index, ++listNodeHead) {//遍历链表数组
LOS_ListInit(listNodeHead);//初始化链表
}
}
//找到内存池和size相匹配的链表头节点,读懂函数之前一定要充分理解LosMultipleDlinkHead中存放的是一个双向链表数组
LITE_OS_SEC_TEXT_MINOR LOS_DL_LIST *OsDLnkMultiHead(VOID *headAddr, UINT32 size)
{
LosMultipleDlinkHead *dlinkHead = (LosMultipleDlinkHead *)headAddr;
UINT32 index = OsLog2(size);
if (index > OS_MAX_MULTI_DLNK_LOG2) {//换算后的对数值大于上限
return NULL;
} else if (index <= OS_MIN_MULTI_DLNK_LOG2) {//换算后的对数值小于下限
index = OS_MIN_MULTI_DLNK_LOG2;//意思是如果申请小于16个字节内存,将分配16个字节的内存
}
//注者会将下句写成 return dlinkHead->listHead[index - OS_MIN_MULTI_DLNK_LOG2];
return dlinkHead->listHead + (index - OS_MIN_MULTI_DLNK_LOG2);//@note_good 这里快速的定位到对应内存块的头节点处
}
#ifdef __cplusplus
#if __cplusplus
}
#endif /* __cplusplus */
#endif /* __cplusplus */
kernel/include/los_memory.h
浏览文件 @ b553c5fc
此差异已折叠。
zzz/git/push.sh
浏览文件 @ b553c5fc
git add -A
git commit -m '静态内存管理中节点处的实现很巧妙,点赞!
git commit -m '注解 动态内存池分成了哪三部分来管理? 代码实现有哪些亮点值得点赞 ?
搜索 @note_pic 方便理解画的字符图
搜索 @note_why 尚未看明白的地方，如果您看明白了，请告知完善
搜索 @note_thinking 一点思考和吐槽的地方
......
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