📄 memory.c
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<!doctype html public "-//W3C//DTD HTML 3.2//EN"><html><head><title>Linux/mm/memory.c</title><meta http-equiv=Content-Type content="text/html; charset=gb2312"><base href="http://oldlinux.org/lxr/http/"></head><body bgcolor=white><div align=center> [<b><i>源代码浏览</i></b>] [<a href="diff/mm/memory.c">区别标定</a>] [<a href="ident">标识符搜索</a>] [<a href="search">文本搜索</a>] [<a href="find">文件搜索</a>]</div><h1 align=center> <a href="http:/"> OldLinux</a> <a href="http:blurb.html"> 交叉引用</a><br> <a href="source/">Linux</a>/<a href="source/mm/">mm</a>/<a href="source/mm/memory.c">memory.c</a></h1><div align=center> <b>版本:</b> [<a href="source/mm/memory.c?v=1.0">1.0</a>] [<a href="source/mm/memory.c?v=0.99.11">0.99.11</a>] [<a href="source/mm/memory.c?v=0.99">0.99</a>] [<a href="source/mm/memory.c?v=0.97">0.97</a>] [<a href="source/mm/memory.c?v=0.96a">0.96a</a>] [<a href="source/mm/memory.c?v=0.95">0.95</a>] [<a href="source/mm/memory.c?v=0.12">0.12</a>] [<b><i>0.11</i></b>] [<a href="source/mm/memory.c?v=0.01">0.01</a>] <br> <b>体系结构:</b> [<b><i>i386</i></b>] <br></div><hr><pre> <a name=L1 href="source/mm/memory.c#L1">1</a> <b><i>/*</i></b> <a name=L2 href="source/mm/memory.c#L2">2</a> <b><i> * linux/mm/memory.c</i></b> <a name=L3 href="source/mm/memory.c#L3">3</a> <b><i> *</i></b> <a name=L4 href="source/mm/memory.c#L4">4</a> <b><i> * (C) 1991 Linus Torvalds</i></b> <a name=L5 href="source/mm/memory.c#L5">5</a> <b><i> */</i></b> <a name=L6 href="source/mm/memory.c#L6">6</a> <a name=L7 href="source/mm/memory.c#L7">7</a> <b><i>/*</i></b> <a name=L8 href="source/mm/memory.c#L8">8</a> <b><i> * demand-loading started 01.12.91 - seems it is high on the list of</i></b> <a name=L9 href="source/mm/memory.c#L9">9</a> <b><i> * things wanted, and it should be easy to implement. - Linus</i></b> <a name=L10 href="source/mm/memory.c#L10">10</a> <b><i> */</i></b> <a name=L11 href="source/mm/memory.c#L11">11</a> <a name=L12 href="source/mm/memory.c#L12">12</a> <b><i>/*</i></b> <a name=L13 href="source/mm/memory.c#L13">13</a> <b><i> * Ok, demand-loading was easy, shared pages a little bit tricker. Shared</i></b> <a name=L14 href="source/mm/memory.c#L14">14</a> <b><i> * pages started 02.12.91, seems to work. - Linus.</i></b> <a name=L15 href="source/mm/memory.c#L15">15</a> <b><i> *</i></b> <a name=L16 href="source/mm/memory.c#L16">16</a> <b><i> * Tested sharing by executing about 30 /bin/sh: under the old kernel it</i></b> <a name=L17 href="source/mm/memory.c#L17">17</a> <b><i> * would have taken more than the 6M I have free, but it worked well as</i></b> <a name=L18 href="source/mm/memory.c#L18">18</a> <b><i> * far as I could see.</i></b> <a name=L19 href="source/mm/memory.c#L19">19</a> <b><i> *</i></b> <a name=L20 href="source/mm/memory.c#L20">20</a> <b><i> * Also corrected some "invalidate()"s - I wasn't doing enough of them.</i></b> <a name=L21 href="source/mm/memory.c#L21">21</a> <b><i> */</i></b> <a name=L22 href="source/mm/memory.c#L22">22</a> <a name=L23 href="source/mm/memory.c#L23">23</a> #include <signal.h> <a name=L24 href="source/mm/memory.c#L24">24</a> <a name=L25 href="source/mm/memory.c#L25">25</a> #include <asm/system.h> <a name=L26 href="source/mm/memory.c#L26">26</a> <a name=L27 href="source/mm/memory.c#L27">27</a> #include <linux/sched.h> <a name=L28 href="source/mm/memory.c#L28">28</a> #include <linux/head.h> <a name=L29 href="source/mm/memory.c#L29">29</a> #include <linux/kernel.h> <a name=L30 href="source/mm/memory.c#L30">30</a> <a name=L31 href="source/mm/memory.c#L31">31</a> volatile void <a href="ident?i=do_exit">do_exit</a>(long code); <a name=L32 href="source/mm/memory.c#L32">32</a> <a name=L33 href="source/mm/memory.c#L33">33</a> static inline volatile void <a href="ident?i=oom">oom</a>(void) <a name=L34 href="source/mm/memory.c#L34">34</a> { <a name=L35 href="source/mm/memory.c#L35">35</a> <a href="ident?i=printk">printk</a>(<i>"out of memory\n\r"</i>); <a name=L36 href="source/mm/memory.c#L36">36</a> <a href="ident?i=do_exit">do_exit</a>(<a href="ident?i=SIGSEGV">SIGSEGV</a>); <a name=L37 href="source/mm/memory.c#L37">37</a> } <a name=L38 href="source/mm/memory.c#L38">38</a> <a name=L39 href="source/mm/memory.c#L39">39</a> #define <a href="ident?i=invalidate">invalidate</a>() \ <a name=L40 href="source/mm/memory.c#L40">40</a> __asm__(<i>"movl %%eax,%%cr3"</i>::<i>"a"</i> (0)) <a name=L41 href="source/mm/memory.c#L41">41</a> <a name=L42 href="source/mm/memory.c#L42">42</a> <b><i>/* these are not to be changed without changing head.s etc */</i></b> <a name=L43 href="source/mm/memory.c#L43">43</a> #define <a href="ident?i=LOW_MEM">LOW_MEM</a> 0x100000 <a name=L44 href="source/mm/memory.c#L44">44</a> #define <a href="ident?i=PAGING_MEMORY">PAGING_MEMORY</a> (15*1024*1024) <a name=L45 href="source/mm/memory.c#L45">45</a> #define <a href="ident?i=PAGING_PAGES">PAGING_PAGES</a> (<a href="ident?i=PAGING_MEMORY">PAGING_MEMORY</a>>>12) <a name=L46 href="source/mm/memory.c#L46">46</a> #define <a href="ident?i=MAP_NR">MAP_NR</a>(addr) (((addr)-<a href="ident?i=LOW_MEM">LOW_MEM</a>)>>12) <a name=L47 href="source/mm/memory.c#L47">47</a> #define <a href="ident?i=USED">USED</a> 100 <a name=L48 href="source/mm/memory.c#L48">48</a> <a name=L49 href="source/mm/memory.c#L49">49</a> #define <a href="ident?i=CODE_SPACE">CODE_SPACE</a>(addr) ((((addr)+4095)&~4095) < \ <a name=L50 href="source/mm/memory.c#L50">50</a> <a href="ident?i=current">current</a>->start_code + <a href="ident?i=current">current</a>->end_code) <a name=L51 href="source/mm/memory.c#L51">51</a> <a name=L52 href="source/mm/memory.c#L52">52</a> static long <a href="ident?i=HIGH_MEMORY">HIGH_MEMORY</a> = 0; <a name=L53 href="source/mm/memory.c#L53">53</a> <a name=L54 href="source/mm/memory.c#L54">54</a> #define <a href="ident?i=copy_page">copy_page</a>(from,to) \ <a name=L55 href="source/mm/memory.c#L55">55</a> __asm__(<i>"cld ; rep ; movsl"</i>::<i>"S"</i> (from),<i>"D"</i> (to),<i>"c"</i> (1024):<i>"cx"</i>,<i>"di"</i>,<i>"si"</i>) <a name=L56 href="source/mm/memory.c#L56">56</a> <a name=L57 href="source/mm/memory.c#L57">57</a> static unsigned char <a href="ident?i=mem_map">mem_map</a> [ <a href="ident?i=PAGING_PAGES">PAGING_PAGES</a> ] = {0,}; <a name=L58 href="source/mm/memory.c#L58">58</a> <a name=L59 href="source/mm/memory.c#L59">59</a> <b><i>/*</i></b> <a name=L60 href="source/mm/memory.c#L60">60</a> <b><i> * Get physical address of first (actually last :-) free page, and mark it</i></b> <a name=L61 href="source/mm/memory.c#L61">61</a> <b><i> * used. If no free pages left, return 0.</i></b> <a name=L62 href="source/mm/memory.c#L62">62</a> <b><i> */</i></b> <a name=L63 href="source/mm/memory.c#L63">63</a> unsigned long <a href="ident?i=get_free_page">get_free_page</a>(void) <a name=L64 href="source/mm/memory.c#L64">64</a> { <a name=L65 href="source/mm/memory.c#L65">65</a> register unsigned long __res asm(<i>"ax"</i>); <a name=L66 href="source/mm/memory.c#L66">66</a> <a name=L67 href="source/mm/memory.c#L67">67</a> __asm__(<i>"std ; repne ; scasb\n\t"</i> <a name=L68 href="source/mm/memory.c#L68">68</a> <i>"jne 1f\n\t"</i> <a name=L69 href="source/mm/memory.c#L69">69</a> <i>"movb $1,1(%%edi)\n\t"</i> <a name=L70 href="source/mm/memory.c#L70">70</a> <i>"sall $12,%%ecx\n\t"</i> <a name=L71 href="source/mm/memory.c#L71">71</a> <i>"addl %2,%%ecx\n\t"</i> <a name=L72 href="source/mm/memory.c#L72">72</a> <i>"movl %%ecx,%%edx\n\t"</i> <a name=L73 href="source/mm/memory.c#L73">73</a> <i>"movl $1024,%%ecx\n\t"</i> <a name=L74 href="source/mm/memory.c#L74">74</a> <i>"leal 4092(%%edx),%%edi\n\t"</i> <a name=L75 href="source/mm/memory.c#L75">75</a> <i>"rep ; stosl\n\t"</i> <a name=L76 href="source/mm/memory.c#L76">76</a> <i>"movl %%edx,%%eax\n"</i> <a name=L77 href="source/mm/memory.c#L77">77</a> <i>"1:"</i> <a name=L78 href="source/mm/memory.c#L78">78</a> :<i>"=a"</i> (__res) <a name=L79 href="source/mm/memory.c#L79">79</a> :<i>""</i> (0),<i>"i"</i> (<a href="ident?i=LOW_MEM">LOW_MEM</a>),<i>"c"</i> (<a href="ident?i=PAGING_PAGES">PAGING_PAGES</a>), <a name=L80 href="source/mm/memory.c#L80">80</a> <i>"D"</i> (<a href="ident?i=mem_map">mem_map</a>+<a href="ident?i=PAGING_PAGES">PAGING_PAGES</a>-1) <a name=L81 href="source/mm/memory.c#L81">81</a> :<i>"di"</i>,<i>"cx"</i>,<i>"dx"</i>); <a name=L82 href="source/mm/memory.c#L82">82</a> return __res; <a name=L83 href="source/mm/memory.c#L83">83</a> } <a name=L84 href="source/mm/memory.c#L84">84</a> <a name=L85 href="source/mm/memory.c#L85">85</a> <b><i>/*</i></b> <a name=L86 href="source/mm/memory.c#L86">86</a> <b><i> * Free a page of memory at physical address 'addr'. Used by</i></b> <a name=L87 href="source/mm/memory.c#L87">87</a> <b><i> * 'free_page_tables()'</i></b> <a name=L88 href="source/mm/memory.c#L88">88</a> <b><i> */</i></b> <a name=L89 href="source/mm/memory.c#L89">89</a> void <a href="ident?i=free_page">free_page</a>(unsigned long addr) <a name=L90 href="source/mm/memory.c#L90">90</a> { <a name=L91 href="source/mm/memory.c#L91">91</a> if (addr < <a href="ident?i=LOW_MEM">LOW_MEM</a>) return; <a name=L92 href="source/mm/memory.c#L92">92</a> if (addr >= <a href="ident?i=HIGH_MEMORY">HIGH_MEMORY</a>) <a name=L93 href="source/mm/memory.c#L93">93</a> <a href="ident?i=panic">panic</a>(<i>"trying to free nonexistent page"</i>); <a name=L94 href="source/mm/memory.c#L94">94</a> addr -= <a href="ident?i=LOW_MEM">LOW_MEM</a>; <a name=L95 href="source/mm/memory.c#L95">95</a> addr >>= 12; <a name=L96 href="source/mm/memory.c#L96">96</a> if (<a href="ident?i=mem_map">mem_map</a>[addr]--) return; <a name=L97 href="source/mm/memory.c#L97">97</a> <a href="ident?i=mem_map">mem_map</a>[addr]=0; <a name=L98 href="source/mm/memory.c#L98">98</a> <a href="ident?i=panic">panic</a>(<i>"trying to free free page"</i>); <a name=L99 href="source/mm/memory.c#L99">99</a> }<a name=L100 href="source/mm/memory.c#L100">100</a> <a name=L101 href="source/mm/memory.c#L101">101</a> <b><i>/*</i></b><a name=L102 href="source/mm/memory.c#L102">102</a> <b><i> * This function frees a continuos block of page tables, as needed</i></b><a name=L103 href="source/mm/memory.c#L103">103</a> <b><i> * by 'exit()'. As does copy_page_tables(), this handles only 4Mb blocks.</i></b><a name=L104 href="source/mm/memory.c#L104">104</a> <b><i> */</i></b><a name=L105 href="source/mm/memory.c#L105">105</a> int <a href="ident?i=free_page_tables">free_page_tables</a>(unsigned long from,unsigned long size)<a name=L106 href="source/mm/memory.c#L106">106</a> {<a name=L107 href="source/mm/memory.c#L107">107</a> unsigned long *pg_table;<a name=L108 href="source/mm/memory.c#L108">108</a> unsigned long * dir, nr;<a name=L109 href="source/mm/memory.c#L109">109</a> <a name=L110 href="source/mm/memory.c#L110">110</a> if (from & 0x3fffff)<a name=L111 href="source/mm/memory.c#L111">111</a> <a href="ident?i=panic">panic</a>(<i>"free_page_tables called with wrong alignment"</i>);<a name=L112 href="source/mm/memory.c#L112">112</a> if (!from)<a name=L113 href="source/mm/memory.c#L113">113</a> <a href="ident?i=panic">panic</a>(<i>"Trying to free up swapper memory space"</i>);<a name=L114 href="source/mm/memory.c#L114">114</a> size = (size + 0x3fffff) >> 22;<a name=L115 href="source/mm/memory.c#L115">115</a> dir = (unsigned long *) ((from>>20) & 0xffc); <b><i>/* _pg_dir = 0 */</i></b><a name=L116 href="source/mm/memory.c#L116">116</a> for ( ; size-->0 ; dir++) {<a name=L117 href="source/mm/memory.c#L117">117</a> if (!(1 & *dir))<a name=L118 href="source/mm/memory.c#L118">118</a> continue;<a name=L119 href="source/mm/memory.c#L119">119</a> pg_table = (unsigned long *) (0xfffff000 & *dir);<a name=L120 href="source/mm/memory.c#L120">120</a> for (nr=0 ; nr<1024 ; nr++) {<a name=L121 href="source/mm/memory.c#L121">121</a> if (1 & *pg_table)<a name=L122 href="source/mm/memory.c#L122">122</a> <a href="ident?i=free_page">free_page</a>(0xfffff000 & *pg_table);<a name=L123 href="source/mm/memory.c#L123">123</a> *pg_table = 0;<a name=L124 href="source/mm/memory.c#L124">124</a> pg_table++;<a name=L125 href="source/mm/memory.c#L125">125</a> }<a name=L126 href="source/mm/memory.c#L126">126</a> <a href="ident?i=free_page">free_page</a>(0xfffff000 & *dir);<a name=L127 href="source/mm/memory.c#L127">127</a> *dir = 0;⌨️ 快捷键说明
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