1# 虚拟内存管理<a name="ZH-CN_TOPIC_0000001123800847"></a> 2 3- [基本概念](#section650193717411) 4- [运行机制](#section072885512412) 5- [开发指导](#section20956116050) 6 - [接口说明](#section166137221657) 7 - [开发流程](#section8752103914513) 8 9 10## 基本概念<a name="section650193717411"></a> 11 12虚拟内存管理是计算机系统管理内存的一种技术。每个进程都有连续的虚拟地址空间，虚拟地址空间的大小由CPU的位数决定，32位的硬件平台可以提供的最大的寻址空间为0-4GiB。整个4GiB空间分成两部分，LiteOS-A内核占据3GiB的高地址空间，1GiB的低地址空间留给进程使用。各个进程空间的虚拟地址空间是独立的，代码、数据互不影响。 13 14系统将虚拟内存分割为称为虚拟页的内存块，大小一般为4KiB或64KiB，LiteOS-A内核默认的页的大小是4KiB，根据需要可以对MMU（Memory Management Units）进行配置。虚拟内存管理操作的最小单位就是一个页，LiteOS-A内核中一个虚拟地址区间region包含地址连续的多个虚拟页，也可只有一个页。同样，物理内存也会按照页大小进行分割，分割后的每个内存块称为页帧。虚拟地址空间划分：内核态占高地址3GiB\(0x40000000 \~ 0xFFFFFFFF\)，用户态占低地址1GiB\(0x01000000 \~ 0x3F000000\)，具体见下表，详细可以查看或配置los\_vm\_zone.h。 15 16**表 1** 内核态地址规划： 17 18<a name="table9988174163613"></a> 19<table><thead align="left"><tr id="row164675173616"><th class="cellrowborder" valign="top" width="19.99%" id="mcps1.2.4.1.1"><p id="p046752361"><a name="p046752361"></a><a name="p046752361"></a>Zone名称</p> 20</th> 21<th class="cellrowborder" valign="top" width="43.13%" id="mcps1.2.4.1.2"><p id="p0461651361"><a name="p0461651361"></a><a name="p0461651361"></a>描述</p> 22</th> 23<th class="cellrowborder" valign="top" width="36.88%" id="mcps1.2.4.1.3"><p id="p446195183611"><a name="p446195183611"></a><a name="p446195183611"></a>属性</p> 24</th> 25</tr> 26</thead> 27<tbody><tr id="row94619516367"><td class="cellrowborder" valign="top" width="19.99%" headers="mcps1.2.4.1.1 "><p id="p1846553363"><a name="p1846553363"></a><a name="p1846553363"></a>DMA zone</p> 28</td> 29<td class="cellrowborder" valign="top" width="43.13%" headers="mcps1.2.4.1.2 "><p id="p3461158364"><a name="p3461158364"></a><a name="p3461158364"></a>供IO设备的DMA使用。</p> 30</td> 31<td class="cellrowborder" valign="top" width="36.88%" headers="mcps1.2.4.1.3 "><p id="p10461152363"><a name="p10461152363"></a><a name="p10461152363"></a>Uncache</p> 32</td> 33</tr> 34<tr id="row246551361"><td class="cellrowborder" valign="top" width="19.99%" headers="mcps1.2.4.1.1 "><p id="p3461259362"><a name="p3461259362"></a><a name="p3461259362"></a>Normal zone</p> 35</td> 36<td class="cellrowborder" valign="top" width="43.13%" headers="mcps1.2.4.1.2 "><p id="p1546056362"><a name="p1546056362"></a><a name="p1546056362"></a>加载内核代码段、数据段、堆和栈的地址区间。</p> 37</td> 38<td class="cellrowborder" valign="top" width="36.88%" headers="mcps1.2.4.1.3 "><p id="p646125143613"><a name="p646125143613"></a><a name="p646125143613"></a>Cache</p> 39</td> 40</tr> 41<tr id="row646165133613"><td class="cellrowborder" valign="top" width="19.99%" headers="mcps1.2.4.1.1 "><p id="p114675183615"><a name="p114675183615"></a><a name="p114675183615"></a>high mem zone</p> 42</td> 43<td class="cellrowborder" valign="top" width="43.13%" headers="mcps1.2.4.1.2 "><p id="p194611583613"><a name="p194611583613"></a><a name="p194611583613"></a>可以分配连续的虚拟内存，但其所映射的物理内存不一定连续。</p> 44</td> 45<td class="cellrowborder" valign="top" width="36.88%" headers="mcps1.2.4.1.3 "><p id="p8461153369"><a name="p8461153369"></a><a name="p8461153369"></a>Cache</p> 46</td> 47</tr> 48</tbody> 49</table> 50 51**表 2** 用户态虚地址规划： 52 53<a name="table19965411366"></a> 54<table><thead align="left"><tr id="row646185183618"><th class="cellrowborder" valign="top" width="20%" id="mcps1.2.4.1.1"><p id="p3466593612"><a name="p3466593612"></a><a name="p3466593612"></a>Zone名称</p> 55</th> 56<th class="cellrowborder" valign="top" width="43.120000000000005%" id="mcps1.2.4.1.2"><p id="p84645143613"><a name="p84645143613"></a><a name="p84645143613"></a>描述</p> 57</th> 58<th class="cellrowborder" valign="top" width="36.88%" id="mcps1.2.4.1.3"><p id="p1146115203615"><a name="p1146115203615"></a><a name="p1146115203615"></a>属性</p> 59</th> 60</tr> 61</thead> 62<tbody><tr id="row7462511363"><td class="cellrowborder" valign="top" width="20%" headers="mcps1.2.4.1.1 "><p id="p2467516363"><a name="p2467516363"></a><a name="p2467516363"></a>代码段</p> 63</td> 64<td class="cellrowborder" valign="top" width="43.120000000000005%" headers="mcps1.2.4.1.2 "><p id="p7472523618"><a name="p7472523618"></a><a name="p7472523618"></a>用户态代码段地址区间。</p> 65</td> 66<td class="cellrowborder" valign="top" width="36.88%" headers="mcps1.2.4.1.3 "><p id="p14476563611"><a name="p14476563611"></a><a name="p14476563611"></a>Cache</p> 67</td> 68</tr> 69<tr id="row34755153614"><td class="cellrowborder" valign="top" width="20%" headers="mcps1.2.4.1.1 "><p id="p194735173612"><a name="p194735173612"></a><a name="p194735173612"></a>堆</p> 70</td> 71<td class="cellrowborder" valign="top" width="43.120000000000005%" headers="mcps1.2.4.1.2 "><p id="p114720518362"><a name="p114720518362"></a><a name="p114720518362"></a>用户态堆地址区间。</p> 72</td> 73<td class="cellrowborder" valign="top" width="36.88%" headers="mcps1.2.4.1.3 "><p id="p9474515364"><a name="p9474515364"></a><a name="p9474515364"></a>Cache</p> 74</td> 75</tr> 76<tr id="row9476518368"><td class="cellrowborder" valign="top" width="20%" headers="mcps1.2.4.1.1 "><p id="p34714516369"><a name="p34714516369"></a><a name="p34714516369"></a>栈</p> 77</td> 78<td class="cellrowborder" valign="top" width="43.120000000000005%" headers="mcps1.2.4.1.2 "><p id="p74705163612"><a name="p74705163612"></a><a name="p74705163612"></a>用户态栈地址区间。</p> 79</td> 80<td class="cellrowborder" valign="top" width="36.88%" headers="mcps1.2.4.1.3 "><p id="p144775143613"><a name="p144775143613"></a><a name="p144775143613"></a>Cache</p> 81</td> 82</tr> 83<tr id="row1047353364"><td class="cellrowborder" valign="top" width="20%" headers="mcps1.2.4.1.1 "><p id="p1947145163615"><a name="p1947145163615"></a><a name="p1947145163615"></a>共享库</p> 84</td> 85<td class="cellrowborder" valign="top" width="43.120000000000005%" headers="mcps1.2.4.1.2 "><p id="p24745193617"><a name="p24745193617"></a><a name="p24745193617"></a>用于加载用户态共享库的地址区间，包括mmap所映射的区间。</p> 86</td> 87<td class="cellrowborder" valign="top" width="36.88%" headers="mcps1.2.4.1.3 "><p id="p11472510363"><a name="p11472510363"></a><a name="p11472510363"></a>Cache</p> 88</td> 89</tr> 90</tbody> 91</table> 92 93## 运行机制<a name="section072885512412"></a> 94 95虚拟内存管理中，虚拟地址空间是连续的，但是其映射的物理内存并不一定是连续的，如下图所示。可执行程序加载运行，CPU访问虚拟地址空间的代码或数据时存在两种情况： 96 97- CPU访问的虚拟地址所在的页，如V0，已经与具体的物理页P0做映射，CPU通过找到进程对应的页表条目（详见[虚实映射](kernel-small-basic-inner-reflect.md)），根据页表条目中的物理地址信息访问物理内存中的内容并返回。 98- CPU访问的虚拟地址所在的页，如V2，没有与具体的物理页做映射，系统会触发缺页异常，系统申请一个物理页，并把相应的信息拷贝到物理页中，并且把物理页的起始地址更新到页表条目中。此时CPU重新执行访问虚拟内存的指令便能够访问到具体的代码或数据。 99 100**图 1** 内存映射示意图<a name="fig144371159135620"></a> 101 102 103## 开发指导<a name="section20956116050"></a> 104 105### 接口说明<a name="section166137221657"></a> 106 107**表 3** 虚拟内存管理模块接口 108 109<a name="table1415203765610"></a> 110<table><thead align="left"><tr id="row134151837125611"><th class="cellrowborder" valign="top" width="12.811281128112812%" id="mcps1.2.4.1.1"><p id="p16415637105612"><a name="p16415637105612"></a><a name="p16415637105612"></a>功能分类</p> 111</th> 112<th class="cellrowborder" valign="top" width="29.84298429842984%" id="mcps1.2.4.1.2"><p id="p11415163718562"><a name="p11415163718562"></a><a name="p11415163718562"></a>接口<strong id="b197068338312"><a name="b197068338312"></a><a name="b197068338312"></a>名称</strong></p> 113</th> 114<th class="cellrowborder" valign="top" width="57.34573457345735%" id="mcps1.2.4.1.3"><p id="p1641533755612"><a name="p1641533755612"></a><a name="p1641533755612"></a>描述</p> 115</th> 116</tr> 117</thead> 118<tbody><tr id="row0415737175610"><td class="cellrowborder" rowspan="5" valign="top" width="12.811281128112812%" headers="mcps1.2.4.1.1 "><p id="p4917132105710"><a name="p4917132105710"></a><a name="p4917132105710"></a>获取进程空间系列接口</p> 119</td> 120<td class="cellrowborder" valign="top" width="29.84298429842984%" headers="mcps1.2.4.1.2 "><p id="p341513372561"><a name="p341513372561"></a><a name="p341513372561"></a>LOS_CurrSpaceGet</p> 121</td> 122<td class="cellrowborder" valign="top" width="57.34573457345735%" headers="mcps1.2.4.1.3 "><p id="p74151037185617"><a name="p74151037185617"></a><a name="p74151037185617"></a>获取当前进程空间结构体指针</p> 123</td> 124</tr> 125<tr id="row1841519376561"><td class="cellrowborder" valign="top" headers="mcps1.2.4.1.1 "><p id="p64151837155618"><a name="p64151837155618"></a><a name="p64151837155618"></a>LOS_SpaceGet</p> 126</td> 127<td class="cellrowborder" valign="top" headers="mcps1.2.4.1.2 "><p id="p441516379562"><a name="p441516379562"></a><a name="p441516379562"></a>获取虚拟地址对应的进程空间结构体指针</p> 128</td> 129</tr> 130<tr id="row536885134010"><td class="cellrowborder" valign="top" headers="mcps1.2.4.1.1 "><p id="p236819594010"><a name="p236819594010"></a><a name="p236819594010"></a>LOS_GetKVmSpace</p> 131</td> 132<td class="cellrowborder" valign="top" headers="mcps1.2.4.1.2 "><p id="p736918564019"><a name="p736918564019"></a><a name="p736918564019"></a>获取内核进程空间结构体指针</p> 133</td> 134</tr> 135<tr id="row11567448194112"><td class="cellrowborder" valign="top" headers="mcps1.2.4.1.1 "><p id="p0568204814115"><a name="p0568204814115"></a><a name="p0568204814115"></a>LOS_GetVmallocSpace</p> 136</td> 137<td class="cellrowborder" valign="top" headers="mcps1.2.4.1.2 "><p id="p05681348204114"><a name="p05681348204114"></a><a name="p05681348204114"></a>获取vmalloc空间结构体指针</p> 138</td> 139</tr> 140<tr id="row1141513373562"><td class="cellrowborder" valign="top" headers="mcps1.2.4.1.1 "><p id="p17765212416"><a name="p17765212416"></a><a name="p17765212416"></a>LOS_GetVmSpaceList</p> 141</td> 142<td class="cellrowborder" valign="top" headers="mcps1.2.4.1.2 "><p id="p1972971913115"><a name="p1972971913115"></a><a name="p1972971913115"></a>获取进程空间链表指针</p> 143</td> 144</tr> 145<tr id="row137812054195014"><td class="cellrowborder" rowspan="15" valign="top" width="12.811281128112812%" headers="mcps1.2.4.1.1 "><p id="p15344719152113"><a name="p15344719152113"></a><a name="p15344719152113"></a>虚拟地址区间region相关的操作</p> 146</td> 147<td class="cellrowborder" valign="top" width="29.84298429842984%" headers="mcps1.2.4.1.2 "><p id="p97821654195014"><a name="p97821654195014"></a><a name="p97821654195014"></a>LOS_RegionFind</p> 148</td> 149<td class="cellrowborder" valign="top" width="57.34573457345735%" headers="mcps1.2.4.1.3 "><p id="p137821854205011"><a name="p137821854205011"></a><a name="p137821854205011"></a>根据起始地址在进程空间内查找是否存在虚拟地址区间</p> 150</td> 151</tr> 152<tr id="row254713575505"><td class="cellrowborder" valign="top" headers="mcps1.2.4.1.1 "><p id="p954785720501"><a name="p954785720501"></a><a name="p954785720501"></a>LOS_RegionRangeFind</p> 153</td> 154<td class="cellrowborder" valign="top" headers="mcps1.2.4.1.2 "><p id="p20547557175013"><a name="p20547557175013"></a><a name="p20547557175013"></a>根据地址区间在进程空间内查找是否存在虚拟地址区间</p> 155</td> 156</tr> 157<tr id="row1692045119"><td class="cellrowborder" valign="top" headers="mcps1.2.4.1.1 "><p id="p1510110115114"><a name="p1510110115114"></a><a name="p1510110115114"></a>LOS_IsRegionFileValid</p> 158</td> 159<td class="cellrowborder" valign="top" headers="mcps1.2.4.1.2 "><p id="p61011045112"><a name="p61011045112"></a><a name="p61011045112"></a>判断虚拟地址区间region是否与文件关联映射</p> 160</td> 161</tr> 162<tr id="row186701424548"><td class="cellrowborder" valign="top" headers="mcps1.2.4.1.1 "><p id="p1967018210546"><a name="p1967018210546"></a><a name="p1967018210546"></a>LOS_RegionAlloc</p> 163</td> 164<td class="cellrowborder" valign="top" headers="mcps1.2.4.1.2 "><p id="p196701221548"><a name="p196701221548"></a><a name="p196701221548"></a>申请空闲的虚拟地址区间</p> 165</td> 166</tr> 167<tr id="row1955586175412"><td class="cellrowborder" valign="top" headers="mcps1.2.4.1.1 "><p id="p555626195420"><a name="p555626195420"></a><a name="p555626195420"></a>LOS_RegionFree</p> 168</td> 169<td class="cellrowborder" valign="top" headers="mcps1.2.4.1.2 "><p id="p85568612547"><a name="p85568612547"></a><a name="p85568612547"></a>释放进程空间内特定的region</p> 170</td> 171</tr> 172<tr id="row259111510282"><td class="cellrowborder" valign="top" headers="mcps1.2.4.1.1 "><p id="p3591135110288"><a name="p3591135110288"></a><a name="p3591135110288"></a>LOS_RegionEndAddr</p> 173</td> 174<td class="cellrowborder" valign="top" headers="mcps1.2.4.1.2 "><p id="p4675183817474"><a name="p4675183817474"></a><a name="p4675183817474"></a>获取指定地址区间region的结束地址</p> 175</td> 176</tr> 177<tr id="row12894115716285"><td class="cellrowborder" valign="top" headers="mcps1.2.4.1.1 "><p id="p889418577280"><a name="p889418577280"></a><a name="p889418577280"></a>LOS_RegionSize</p> 178</td> 179<td class="cellrowborder" valign="top" headers="mcps1.2.4.1.2 "><p id="p68941757112813"><a name="p68941757112813"></a><a name="p68941757112813"></a>获取region的大小</p> 180</td> 181</tr> 182<tr id="row14931456182812"><td class="cellrowborder" valign="top" headers="mcps1.2.4.1.1 "><p id="p1293135611287"><a name="p1293135611287"></a><a name="p1293135611287"></a>LOS_IsRegionTypeFile</p> 183</td> 184<td class="cellrowborder" valign="top" headers="mcps1.2.4.1.2 "><p id="p1393185613288"><a name="p1393185613288"></a><a name="p1393185613288"></a>判断是否为文件内存映射</p> 185</td> 186</tr> 187<tr id="row12153854132814"><td class="cellrowborder" valign="top" headers="mcps1.2.4.1.1 "><p id="p115335452819"><a name="p115335452819"></a><a name="p115335452819"></a>LOS_IsRegionPermUserReadOnly</p> 188</td> 189<td class="cellrowborder" valign="top" headers="mcps1.2.4.1.2 "><p id="p1415314545285"><a name="p1415314545285"></a><a name="p1415314545285"></a>判断地址区间是否是用户空间只读属性</p> 190</td> 191</tr> 192<tr id="row29249497282"><td class="cellrowborder" valign="top" headers="mcps1.2.4.1.1 "><p id="p1492415495284"><a name="p1492415495284"></a><a name="p1492415495284"></a>LOS_IsRegionFlagPrivateOnly</p> 193</td> 194<td class="cellrowborder" valign="top" headers="mcps1.2.4.1.2 "><p id="p1392434982817"><a name="p1392434982817"></a><a name="p1392434982817"></a>判断地址区间是否是具有私有属性</p> 195</td> 196</tr> 197<tr id="row1233194042814"><td class="cellrowborder" valign="top" headers="mcps1.2.4.1.1 "><p id="p3339401289"><a name="p3339401289"></a><a name="p3339401289"></a>LOS_SetRegionTypeFile</p> 198</td> 199<td class="cellrowborder" valign="top" headers="mcps1.2.4.1.2 "><p id="p193317409285"><a name="p193317409285"></a><a name="p193317409285"></a>设置文件内存映射属性</p> 200</td> 201</tr> 202<tr id="row178971473283"><td class="cellrowborder" valign="top" headers="mcps1.2.4.1.1 "><p id="p4898184782815"><a name="p4898184782815"></a><a name="p4898184782815"></a>LOS_IsRegionTypeDev</p> 203</td> 204<td class="cellrowborder" valign="top" headers="mcps1.2.4.1.2 "><p id="p11898144722818"><a name="p11898144722818"></a><a name="p11898144722818"></a>判断是否为设备内存映射</p> 205</td> 206</tr> 207<tr id="row11137546152811"><td class="cellrowborder" valign="top" headers="mcps1.2.4.1.1 "><p id="p20137194672812"><a name="p20137194672812"></a><a name="p20137194672812"></a>LOS_SetRegionTypeDev</p> 208</td> 209<td class="cellrowborder" valign="top" headers="mcps1.2.4.1.2 "><p id="p81384462287"><a name="p81384462287"></a><a name="p81384462287"></a>设置设备内存映射属性</p> 210</td> 211</tr> 212<tr id="row1023564216285"><td class="cellrowborder" valign="top" headers="mcps1.2.4.1.1 "><p id="p92351842162819"><a name="p92351842162819"></a><a name="p92351842162819"></a>LOS_IsRegionTypeAnon</p> 213</td> 214<td class="cellrowborder" valign="top" headers="mcps1.2.4.1.2 "><p id="p6235842132818"><a name="p6235842132818"></a><a name="p6235842132818"></a>判断是否为匿名映射</p> 215</td> 216</tr> 217<tr id="row1646364402813"><td class="cellrowborder" valign="top" headers="mcps1.2.4.1.1 "><p id="p44631644152814"><a name="p44631644152814"></a><a name="p44631644152814"></a>LOS_SetRegionTypeAnon</p> 218</td> 219<td class="cellrowborder" valign="top" headers="mcps1.2.4.1.2 "><p id="p174631844182818"><a name="p174631844182818"></a><a name="p174631844182818"></a>设置匿名映射属性</p> 220</td> 221</tr> 222<tr id="row038233717288"><td class="cellrowborder" rowspan="5" valign="top" width="12.811281128112812%" headers="mcps1.2.4.1.1 "><p id="p6820331185317"><a name="p6820331185317"></a><a name="p6820331185317"></a>地址校验</p> 223</td> 224<td class="cellrowborder" valign="top" width="29.84298429842984%" headers="mcps1.2.4.1.2 "><p id="p838383720282"><a name="p838383720282"></a><a name="p838383720282"></a>LOS_IsUserAddress</p> 225</td> 226<td class="cellrowborder" valign="top" width="57.34573457345735%" headers="mcps1.2.4.1.3 "><p id="p12383837102818"><a name="p12383837102818"></a><a name="p12383837102818"></a>判断地址是否在用户态空间</p> 227</td> 228</tr> 229<tr id="row61506354284"><td class="cellrowborder" valign="top" headers="mcps1.2.4.1.1 "><p id="p2151113517288"><a name="p2151113517288"></a><a name="p2151113517288"></a>LOS_IsUserAddressRange</p> 230</td> 231<td class="cellrowborder" valign="top" headers="mcps1.2.4.1.2 "><p id="p615123552814"><a name="p615123552814"></a><a name="p615123552814"></a>判断地址区间是否在用户态空间</p> 232</td> 233</tr> 234<tr id="row18301515194210"><td class="cellrowborder" valign="top" headers="mcps1.2.4.1.1 "><p id="p19301141519421"><a name="p19301141519421"></a><a name="p19301141519421"></a>LOS_IsKernelAddress</p> 235</td> 236<td class="cellrowborder" valign="top" headers="mcps1.2.4.1.2 "><p id="p730110154427"><a name="p730110154427"></a><a name="p730110154427"></a>判断地址是否在内核空间</p> 237</td> 238</tr> 239<tr id="row191211718204213"><td class="cellrowborder" valign="top" headers="mcps1.2.4.1.1 "><p id="p1112121812423"><a name="p1112121812423"></a><a name="p1112121812423"></a>LOS_IsKernelAddressRange</p> 240</td> 241<td class="cellrowborder" valign="top" headers="mcps1.2.4.1.2 "><p id="p6122101814219"><a name="p6122101814219"></a><a name="p6122101814219"></a>判断地址区间是否在内核空间</p> 242</td> 243</tr> 244<tr id="row774964092115"><td class="cellrowborder" valign="top" headers="mcps1.2.4.1.1 "><p id="p17152102415416"><a name="p17152102415416"></a><a name="p17152102415416"></a>LOS_IsRangeInSpace</p> 245</td> 246<td class="cellrowborder" valign="top" headers="mcps1.2.4.1.2 "><p id="p115218248547"><a name="p115218248547"></a><a name="p115218248547"></a>判断地址区间是否在进程空间内</p> 247</td> 248</tr> 249<tr id="row179196525521"><td class="cellrowborder" rowspan="3" valign="top" width="12.811281128112812%" headers="mcps1.2.4.1.1 "><p id="p153501191535"><a name="p153501191535"></a><a name="p153501191535"></a>vmalloc操作</p> 250</td> 251<td class="cellrowborder" valign="top" width="29.84298429842984%" headers="mcps1.2.4.1.2 "><p id="p152945155531"><a name="p152945155531"></a><a name="p152945155531"></a>LOS_VMalloc</p> 252</td> 253<td class="cellrowborder" valign="top" width="57.34573457345735%" headers="mcps1.2.4.1.3 "><p id="p1229461512535"><a name="p1229461512535"></a><a name="p1229461512535"></a>vmalloc申请内存</p> 254</td> 255</tr> 256<tr id="row1934135935211"><td class="cellrowborder" valign="top" headers="mcps1.2.4.1.1 "><p id="p162941115155315"><a name="p162941115155315"></a><a name="p162941115155315"></a>LOS_VFree</p> 257</td> 258<td class="cellrowborder" valign="top" headers="mcps1.2.4.1.2 "><p id="p12294171516536"><a name="p12294171516536"></a><a name="p12294171516536"></a>vmalloc释放内存</p> 259</td> 260</tr> 261<tr id="row944214919304"><td class="cellrowborder" valign="top" headers="mcps1.2.4.1.1 "><p id="p644229163016"><a name="p644229163016"></a><a name="p644229163016"></a>LOS_IsVmallocAddress</p> 262</td> 263<td class="cellrowborder" valign="top" headers="mcps1.2.4.1.2 "><p id="p1344220993011"><a name="p1344220993011"></a><a name="p1344220993011"></a>判断地址是否是通过vmalloc申请的</p> 264</td> 265</tr> 266<tr id="row72131845145315"><td class="cellrowborder" rowspan="4" valign="top" width="12.811281128112812%" headers="mcps1.2.4.1.1 "><p id="p84847816543"><a name="p84847816543"></a><a name="p84847816543"></a>内存申请系列接口</p> 267</td> 268<td class="cellrowborder" valign="top" width="29.84298429842984%" headers="mcps1.2.4.1.2 "><p id="p8787345546"><a name="p8787345546"></a><a name="p8787345546"></a>LOS_KernelMalloc</p> 269</td> 270<td class="cellrowborder" valign="top" width="57.34573457345735%" headers="mcps1.2.4.1.3 "><p id="p17787444543"><a name="p17787444543"></a><a name="p17787444543"></a>申请小于16KiB的内存则通过堆内存池获取，否则申请多个连续物理页</p> 271</td> 272</tr> 273<tr id="row48491549145311"><td class="cellrowborder" valign="top" headers="mcps1.2.4.1.1 "><p id="p14787149541"><a name="p14787149541"></a><a name="p14787149541"></a>LOS_KernelMallocAlign</p> 274</td> 275<td class="cellrowborder" valign="top" headers="mcps1.2.4.1.2 "><p id="p478719411543"><a name="p478719411543"></a><a name="p478719411543"></a>申请具有对齐属性的内存，申请规则：申请小于16KiB的内存则通过堆内存池获取，否则申请多个连续物理页</p> 276</td> 277</tr> 278<tr id="row151093538536"><td class="cellrowborder" valign="top" headers="mcps1.2.4.1.1 "><p id="p15787134185412"><a name="p15787134185412"></a><a name="p15787134185412"></a>LOS_KernelFree</p> 279</td> 280<td class="cellrowborder" valign="top" headers="mcps1.2.4.1.2 "><p id="p878712410546"><a name="p878712410546"></a><a name="p878712410546"></a>释放内核堆内存</p> 281</td> 282</tr> 283<tr id="row5126856205319"><td class="cellrowborder" valign="top" headers="mcps1.2.4.1.1 "><p id="p197871646545"><a name="p197871646545"></a><a name="p197871646545"></a>LOS_KernelRealloc</p> 284</td> 285<td class="cellrowborder" valign="top" headers="mcps1.2.4.1.2 "><p id="p378813416547"><a name="p378813416547"></a><a name="p378813416547"></a>重新分配内核内存空间</p> 286</td> 287</tr> 288<tr id="row12397132718549"><td class="cellrowborder" rowspan="5" valign="top" width="12.811281128112812%" headers="mcps1.2.4.1.1 "><p id="p112971954115419"><a name="p112971954115419"></a><a name="p112971954115419"></a>其他</p> 289</td> 290<td class="cellrowborder" valign="top" width="29.84298429842984%" headers="mcps1.2.4.1.2 "><p id="p2777034145414"><a name="p2777034145414"></a><a name="p2777034145414"></a>LOS_PaddrQuery</p> 291</td> 292<td class="cellrowborder" valign="top" width="57.34573457345735%" headers="mcps1.2.4.1.3 "><p id="p13777834115413"><a name="p13777834115413"></a><a name="p13777834115413"></a>根据虚拟地址获取对应的物理地址</p> 293</td> 294</tr> 295<tr id="row5558122119542"><td class="cellrowborder" valign="top" headers="mcps1.2.4.1.1 "><p id="p9558421155418"><a name="p9558421155418"></a><a name="p9558421155418"></a>LOS_VmSpaceFree</p> 296</td> 297<td class="cellrowborder" valign="top" headers="mcps1.2.4.1.2 "><p id="p755852119545"><a name="p755852119545"></a><a name="p755852119545"></a>释放进程空间，包括虚拟内存区间、页表等信息</p> 298</td> 299</tr> 300<tr id="row15860142919544"><td class="cellrowborder" valign="top" headers="mcps1.2.4.1.1 "><p id="p168603298547"><a name="p168603298547"></a><a name="p168603298547"></a>LOS_VmSpaceReserve</p> 301</td> 302<td class="cellrowborder" valign="top" headers="mcps1.2.4.1.2 "><p id="p12860429185410"><a name="p12860429185410"></a><a name="p12860429185410"></a>在进程空间中预留一块内存空间</p> 303</td> 304</tr> 305<tr id="row394217543569"><td class="cellrowborder" valign="top" headers="mcps1.2.4.1.1 "><p id="p11943125419566"><a name="p11943125419566"></a><a name="p11943125419566"></a>LOS_VaddrToPaddrMmap</p> 306</td> 307<td class="cellrowborder" valign="top" headers="mcps1.2.4.1.2 "><p id="p16943954105613"><a name="p16943954105613"></a><a name="p16943954105613"></a>将指定长度的物理地址区间与虚拟地址区间做映射，需提前申请物理地址区间</p> 308</td> 309</tr> 310<tr id="row18527155718"><td class="cellrowborder" valign="top" headers="mcps1.2.4.1.1 "><p id="p118526110579"><a name="p118526110579"></a><a name="p118526110579"></a>LOS_UserSpaceVmAlloc</p> 311</td> 312<td class="cellrowborder" valign="top" headers="mcps1.2.4.1.2 "><p id="p1485214117575"><a name="p1485214117575"></a><a name="p1485214117575"></a>根据地址、大小、权限等信息在用户进程空间内申请地址区间region</p> 313</td> 314</tr> 315</tbody> 316</table> 317 318### 开发流程<a name="section8752103914513"></a> 319 320虚拟内存相关接口的使用： 321 3221. 根据进程空间获取的系列接口可以得到进程空间结构体，进而可以读取结构体相应信息。 3232. 对虚拟地址区间做相关操作： 324 - 通过LOS\_RegionAlloc申请虚拟地址区间； 325 326 - 通过LOS\_RegionFind、LOS\_RegionRangeFind可以查询是否存在相应的地址区间； 327 - 通过LOS\_RegionFree释放虚拟地址区间。 328 3293. vmalloc接口及内存申请系列接口可以在内核中根据需要申请内存。 330 331> **说明：** 332>内存申请系列接口申请的内存要求物理内存是连续的，当系统内存无法满足大块连续内存的申请条件时会申请失败，一般适用于小块内存的申请；vmalloc相关接口申请的内存可以获得不连续的物理内存，但其是以页（当前系统一个页为4096字节）为单位的，当需要申请以页为整数倍的内存时可以通过vmalloc申请，例如文件系统中文件读取需要较大的缓存，便可以通过vmalloc相关接口申请内存。 333 334
