{"id":1440,"date":"2018-06-21T21:00:34","date_gmt":"2018-06-21T13:00:34","guid":{"rendered":"https:\/\/damogame.cn:15443\/wordpress\/?p=1440"},"modified":"2018-06-21T21:00:34","modified_gmt":"2018-06-21T13:00:34","slug":"linux%e8%bf%9b%e7%a8%8b%e9%97%b4%e9%80%9a%e4%bf%a1%ef%bc%9a%e5%85%b1%e4%ba%ab%e5%86%85%e5%ad%98-%ef%bc%88%e4%b8%8b%ef%bc%89","status":"publish","type":"post","link":"https:\/\/i007.cc\/wordpress\/archives\/1440","title":{"rendered":"Linux\u8fdb\u7a0b\u95f4\u901a\u4fe1\uff1a\u5171\u4eab\u5185\u5b58 \uff08\u4e0b\uff09"},"content":{"rendered":"<h1 class=\"col-article-title\">Linux\u8fdb\u7a0b\u95f4\u901a\u4fe1\uff1a\u5171\u4eab\u5185\u5b58 \uff08\u4e0b\uff09<\/h1>\n<div class=\"col-markdown-nav absolute\">\n<h2 class=\"nav-title\">\u5728\u8fd9\u7bc7\u6587\u7ae0\u4e2d\uff1a<\/h2>\n<ul class=\"col-markdown-nav-list\">\n<li><a class=\"active\" title=\"POSIX\u5171\u4eab\u5185\u5b58\" data-key=\"2.1\">POSIX\u5171\u4eab\u5185\u5b58<\/a><\/li>\n<li><a title=\"\u6700\u540e\" data-key=\"2.2\">\u6700\u540e<\/a><\/li>\n<\/ul>\n<\/div>\n<div class=\"c-markdown J-articleContent\">\n<p>\u63a5<a href=\"https:\/\/www.qcloud.com\/community\/article\/347803\" target=\"_blank\" rel=\"noopener\">Linux\u8fdb\u7a0b\u95f4\u901a\u4fe1:\u5171\u4eab\u5185\u5b58 \uff08\u4e0a\uff09<\/a><\/p>\n<h2>POSIX\u5171\u4eab\u5185\u5b58<\/h2>\n<p>POSIX\u5171\u4eab\u5185\u5b58\u5b9e\u9645\u4e0a\u6beb\u65e0\u65b0\u610f\uff0c\u5b83\u672c\u8d28\u4e0a\u5c31\u662fmmap\u5bf9\u6587\u4ef6\u7684\u5171\u4eab\u65b9\u5f0f\u6620\u5c04\uff0c\u53ea\u4e0d\u8fc7\u6620\u5c04\u7684\u662ftmpfs\u6587\u4ef6\u7cfb\u7edf\u4e0a\u7684\u6587\u4ef6\u3002<\/p>\n<p>\u4ec0\u4e48\u662ftmpfs\uff1fLinux\u63d0\u4f9b\u4e00\u79cd\u201c\u4e34\u65f6\u201d\u6587\u4ef6\u7cfb\u7edf\u53eb\u505atmpfs\uff0c\u5b83\u53ef\u4ee5\u5c06\u5185\u5b58\u7684\u4e00\u90e8\u5206\u7a7a\u95f4\u62ff\u6765\u5f53\u505a\u6587\u4ef6\u7cfb\u7edf\u4f7f\u7528\uff0c\u4f7f\u5185\u5b58\u7a7a\u95f4\u53ef\u4ee5\u5f53\u505a\u76ee\u5f55\u6587\u4ef6\u6765\u7528\u3002\u73b0\u5728\u7edd\u5927\u591a\u6570Linux\u7cfb\u7edf\u90fd\u6709\u4e00\u4e2a\u53eb\u505a\/dev\/shm\u7684tmpfs\u76ee\u5f55\uff0c\u5c31\u662f\u8fd9\u6837\u4e00\u79cd\u5b58\u5728\u3002\u5177\u4f53\u4f7f\u7528\u65b9\u6cd5\uff0c\u5927\u5bb6\u53ef\u4ee5\u53c2\u8003\u6211\u7684\u53e6\u4e00\u7bc7\u6587\u7ae0\u300aLinux\u5185\u5b58\u4e2d\u7684Cache\u771f\u7684\u80fd\u88ab\u56de\u6536\u4e48\uff1f\u300b\u3002<\/p>\n<p>Linux\u63d0\u4f9b\u7684POSIX\u5171\u4eab\u5185\u5b58\uff0c\u5b9e\u9645\u4e0a\u5c31\u662f\u5728\/dev\/shm\u4e0b\u521b\u5efa\u4e00\u4e2a\u6587\u4ef6\uff0c\u5e76\u5c06\u5176mmap\u4e4b\u540e\u6620\u5c04\u5176\u5185\u5b58\u5730\u5740\u5373\u53ef\u3002\u6211\u4eec\u901a\u8fc7\u5b83\u7ed9\u5b9a\u7684\u4e00\u5957\u53c2\u6570\u5c31\u80fd\u731c\u5230\u5b83\u7684\u4e3b\u8981\u51fd\u6570shm_open\u65e0\u975e\u5c31\u662fopen\u7cfb\u7edf\u8c03\u7528\u7684\u4e00\u4e2a\u5c01\u88c5\u3002\u5927\u5bb6\u53ef\u4ee5\u901a\u8fc7man shm_overview\u6765\u67e5\u770b\u76f8\u5173\u64cd\u4f5c\u7684\u65b9\u6cd5\u3002\u4f7f\u7528\u4ee3\u7801\u5982\u4e0b\uff1a<\/p>\n<pre class=\"prism-token token  language-javascript\"><span class=\"token punctuation\">[<\/span>root@zorrozou<span class=\"token operator\">-<\/span>pc0 sharemem<span class=\"token punctuation\">]<\/span># cat racing_posix_shm<span class=\"token punctuation\">.<\/span>c \r\n#include <span class=\"token operator\">&lt;<\/span>unistd<span class=\"token punctuation\">.<\/span>h<span class=\"token operator\">&gt;<\/span>\r\n#include <span class=\"token operator\">&lt;<\/span>stdlib<span class=\"token punctuation\">.<\/span>h<span class=\"token operator\">&gt;<\/span>\r\n#include <span class=\"token operator\">&lt;<\/span>stdio<span class=\"token punctuation\">.<\/span>h<span class=\"token operator\">&gt;<\/span>\r\n#include <span class=\"token operator\">&lt;<\/span>errno<span class=\"token punctuation\">.<\/span>h<span class=\"token operator\">&gt;<\/span>\r\n#include <span class=\"token operator\">&lt;<\/span>fcntl<span class=\"token punctuation\">.<\/span>h<span class=\"token operator\">&gt;<\/span>\r\n#include <span class=\"token operator\">&lt;<\/span>string<span class=\"token punctuation\">.<\/span>h<span class=\"token operator\">&gt;<\/span>\r\n#include <span class=\"token operator\">&lt;<\/span>sys<span class=\"token operator\">\/<\/span>file<span class=\"token punctuation\">.<\/span>h<span class=\"token operator\">&gt;<\/span>\r\n#include <span class=\"token operator\">&lt;<\/span>wait<span class=\"token punctuation\">.<\/span>h<span class=\"token operator\">&gt;<\/span>\r\n#include <span class=\"token operator\">&lt;<\/span>sys<span class=\"token operator\">\/<\/span>mman<span class=\"token punctuation\">.<\/span>h<span class=\"token operator\">&gt;<\/span>\r\n\r\n#define COUNT <span class=\"token number\">100<\/span>\r\n#define SHMPATH <span class=\"token string\">\"shm\"<\/span>\r\n\r\nint <span class=\"token function\">do_child<\/span><span class=\"token punctuation\">(<\/span>char <span class=\"token operator\">*<\/span> shmpath<span class=\"token punctuation\">)<\/span>\r\n<span class=\"token punctuation\">{<\/span>\r\n    int interval<span class=\"token punctuation\">,<\/span> shmfd<span class=\"token punctuation\">,<\/span> ret<span class=\"token punctuation\">;<\/span>\r\n    int <span class=\"token operator\">*<\/span>shm_p<span class=\"token punctuation\">;<\/span>\r\n    <span class=\"token comment\">\/* \u4f7f\u7528shm_open\u8bbf\u95ee\u4e00\u4e2a\u5df2\u7ecf\u521b\u5efa\u7684POSIX\u5171\u4eab\u5185\u5b58 *\/<\/span>\r\n    shmfd <span class=\"token operator\">=<\/span> <span class=\"token function\">shm_open<\/span><span class=\"token punctuation\">(<\/span>shmpath<span class=\"token punctuation\">,<\/span> O_RDWR<span class=\"token punctuation\">,<\/span> <span class=\"token number\">0600<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>shmfd <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>\r\n        <span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">\"shm_open()\"<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n        <span class=\"token function\">exit<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n    <span class=\"token punctuation\">}<\/span>\r\n\r\n    <span class=\"token comment\">\/* \u4f7f\u7528mmap\u5c06\u5bf9\u5e94\u7684tmpfs\u6587\u4ef6\u6620\u5c04\u5230\u672c\u8fdb\u7a0b\u5185\u5b58 *\/<\/span>\r\n    shm_p <span class=\"token operator\">=<\/span> <span class=\"token punctuation\">(<\/span>int <span class=\"token operator\">*<\/span><span class=\"token punctuation\">)<\/span><span class=\"token function\">mmap<\/span><span class=\"token punctuation\">(<\/span>NULL<span class=\"token punctuation\">,<\/span> <span class=\"token function\">sizeof<\/span><span class=\"token punctuation\">(<\/span>int<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span> PROT_WRITE<span class=\"token operator\">|<\/span>PROT_READ<span class=\"token punctuation\">,<\/span> MAP_SHARED<span class=\"token punctuation\">,<\/span> shmfd<span class=\"token punctuation\">,<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>MAP_FAILED <span class=\"token operator\">==<\/span> shm_p<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>\r\n        <span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">\"mmap()\"<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n        <span class=\"token function\">exit<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n    <span class=\"token punctuation\">}<\/span>\r\n    <span class=\"token comment\">\/* critical section *\/<\/span>\r\n    interval <span class=\"token operator\">=<\/span> <span class=\"token operator\">*<\/span>shm_p<span class=\"token punctuation\">;<\/span>\r\n    interval<span class=\"token operator\">++<\/span><span class=\"token punctuation\">;<\/span>\r\n    <span class=\"token function\">usleep<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n    <span class=\"token operator\">*<\/span>shm_p <span class=\"token operator\">=<\/span> interval<span class=\"token punctuation\">;<\/span>\r\n    <span class=\"token comment\">\/* critical section *\/<\/span>\r\n    <span class=\"token function\">munmap<\/span><span class=\"token punctuation\">(<\/span>shm_p<span class=\"token punctuation\">,<\/span> <span class=\"token function\">sizeof<\/span><span class=\"token punctuation\">(<\/span>int<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n    <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>shmfd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n\r\n    <span class=\"token function\">exit<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n<span class=\"token punctuation\">}<\/span>\r\n\r\nint <span class=\"token function\">main<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span>\r\n<span class=\"token punctuation\">{<\/span>\r\n    pid_t pid<span class=\"token punctuation\">;<\/span>\r\n    int count<span class=\"token punctuation\">,<\/span> shmfd<span class=\"token punctuation\">,<\/span> ret<span class=\"token punctuation\">;<\/span>\r\n    int <span class=\"token operator\">*<\/span>shm_p<span class=\"token punctuation\">;<\/span>\r\n\r\n    <span class=\"token comment\">\/* \u521b\u5efa\u4e00\u4e2aPOSIX\u5171\u4eab\u5185\u5b58 *\/<\/span>\r\n    shmfd <span class=\"token operator\">=<\/span> <span class=\"token function\">shm_open<\/span><span class=\"token punctuation\">(<\/span>SHMPATH<span class=\"token punctuation\">,<\/span> O_RDWR<span class=\"token operator\">|<\/span>O_CREAT<span class=\"token operator\">|<\/span>O_TRUNC<span class=\"token punctuation\">,<\/span> <span class=\"token number\">0600<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>shmfd <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>\r\n        <span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">\"shm_open()\"<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n        <span class=\"token function\">exit<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n    <span class=\"token punctuation\">}<\/span>\r\n\r\n    <span class=\"token comment\">\/* \u4f7f\u7528ftruncate\u8bbe\u7f6e\u5171\u4eab\u5185\u5b58\u6bb5\u5927\u5c0f *\/<\/span>\r\n    ret <span class=\"token operator\">=<\/span> <span class=\"token function\">ftruncate<\/span><span class=\"token punctuation\">(<\/span>shmfd<span class=\"token punctuation\">,<\/span> <span class=\"token function\">sizeof<\/span><span class=\"token punctuation\">(<\/span>int<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>ret <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>\r\n        <span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">\"ftruncate()\"<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n        <span class=\"token function\">exit<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n    <span class=\"token punctuation\">}<\/span>\r\n\r\n    <span class=\"token comment\">\/* \u4f7f\u7528mmap\u5c06\u5bf9\u5e94\u7684tmpfs\u6587\u4ef6\u6620\u5c04\u5230\u672c\u8fdb\u7a0b\u5185\u5b58 *\/<\/span>\r\n    shm_p <span class=\"token operator\">=<\/span> <span class=\"token punctuation\">(<\/span>int <span class=\"token operator\">*<\/span><span class=\"token punctuation\">)<\/span><span class=\"token function\">mmap<\/span><span class=\"token punctuation\">(<\/span>NULL<span class=\"token punctuation\">,<\/span> <span class=\"token function\">sizeof<\/span><span class=\"token punctuation\">(<\/span>int<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span> PROT_WRITE<span class=\"token operator\">|<\/span>PROT_READ<span class=\"token punctuation\">,<\/span> MAP_SHARED<span class=\"token punctuation\">,<\/span> shmfd<span class=\"token punctuation\">,<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>MAP_FAILED <span class=\"token operator\">==<\/span> shm_p<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>\r\n        <span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">\"mmap()\"<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n        <span class=\"token function\">exit<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n    <span class=\"token punctuation\">}<\/span>\r\n\r\n    <span class=\"token operator\">*<\/span>shm_p <span class=\"token operator\">=<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span>\r\n\r\n    <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span>count<span class=\"token operator\">=<\/span><span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span>count<span class=\"token operator\">&lt;<\/span>COUNT<span class=\"token punctuation\">;<\/span>count<span class=\"token operator\">++<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>\r\n        pid <span class=\"token operator\">=<\/span> <span class=\"token function\">fork<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>pid <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>\r\n            <span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">\"fork()\"<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n            <span class=\"token function\">exit<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n        <span class=\"token punctuation\">}<\/span>\r\n\r\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>pid <span class=\"token operator\">==<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>\r\n            <span class=\"token function\">do_child<\/span><span class=\"token punctuation\">(<\/span>SHMPATH<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n        <span class=\"token punctuation\">}<\/span>\r\n    <span class=\"token punctuation\">}<\/span>\r\n\r\n    <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span>count<span class=\"token operator\">=<\/span><span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span>count<span class=\"token operator\">&lt;<\/span>COUNT<span class=\"token punctuation\">;<\/span>count<span class=\"token operator\">++<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>\r\n        <span class=\"token function\">wait<\/span><span class=\"token punctuation\">(<\/span>NULL<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n    <span class=\"token punctuation\">}<\/span>\r\n\r\n    <span class=\"token function\">printf<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">\"shm_p: %d\\n\"<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">*<\/span>shm_p<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n    <span class=\"token function\">munmap<\/span><span class=\"token punctuation\">(<\/span>shm_p<span class=\"token punctuation\">,<\/span> <span class=\"token function\">sizeof<\/span><span class=\"token punctuation\">(<\/span>int<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n    <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>shmfd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n    <span class=\"token comment\">\/\/sleep(3000);<\/span>\r\n    <span class=\"token function\">shm_unlink<\/span><span class=\"token punctuation\">(<\/span>SHMPATH<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n    <span class=\"token function\">exit<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n<span class=\"token punctuation\">}<\/span><\/pre>\n<p>\u7f16\u8bd1\u6267\u884c\u8fd9\u4e2a\u7a0b\u5e8f\u9700\u8981\u6307\u5b9a\u4e00\u4e2a\u989d\u5916rt\u7684\u5e93\uff0c\u53ef\u4ee5\u4f7f\u7528\u5982\u4e0b\u547d\u4ee4\u8fdb\u884c\u7f16\u8bd1\uff1a<\/p>\n<pre class=\"prism-token token  language-javascript\"><span class=\"token punctuation\">[<\/span>root@zorrozou<span class=\"token operator\">-<\/span>pc0 sharemem<span class=\"token punctuation\">]<\/span># gcc <span class=\"token operator\">-<\/span>o racing_posix_shm <span class=\"token operator\">-<\/span>lrt racing_posix_shm<span class=\"token punctuation\">.<\/span>c<\/pre>\n<p>\u5bf9\u4e8e\u8fd9\u4e2a\u7a0b\u5e8f\uff0c\u6211\u4eec\u9700\u8981\u89e3\u91ca\u4ee5\u4e0b\u51e0\u70b9\uff1a<\/p>\n<ol class=\"ol-level-0\">\n<li>shm_open\u7684SHMPATH\u53c2\u6570\u662f\u4e00\u4e2a\u8def\u5f84\uff0c\u8fd9\u4e2a\u8def\u5f84\u9ed8\u8ba4\u653e\u5728\u7cfb\u7edf\u7684\/dev\/shm\u76ee\u5f55\u4e0b\u3002\u8fd9\u662fshm_open\u5df2\u7ecf\u5c01\u88c5\u597d\u7684\uff0c\u4fdd\u8bc1\u4e86\u6587\u4ef6\u4e00\u5b9a\u4f1a\u4f7f\u7528tmpfs\u3002<\/li>\n<li>shm_open\u5b9e\u9645\u4e0a\u5c31\u662fopen\u7cfb\u7edf\u8c03\u7528\u7684\u5c01\u88c5\u3002\u6211\u4eec\u5f53\u7136\u5b8c\u5168\u53ef\u4ee5\u4f7f\u7528open\u7684\u65b9\u5f0f\u6a21\u62df\u8fd9\u4e2a\u65b9\u6cd5\u3002<\/li>\n<li>\u4f7f\u7528ftruncate\u65b9\u6cd5\u6765\u8bbe\u7f6e\u201c\u5171\u4eab\u5185\u5b58\u201d\u7684\u5927\u5c0f\u3002\u5176\u5b9e\u5c31\u662f\u66f4\u6539\u6587\u4ef6\u7684\u957f\u5ea6\u3002<\/li>\n<li>\u8981\u4ee5\u5171\u4eab\u65b9\u5f0f\u505ammap\u6620\u5c04\uff0c\u5e76\u4e14\u6307\u5b9a\u6587\u4ef6\u63cf\u8ff0\u7b26\u4e3ashmfd\u3002<\/li>\n<li>shm_unlink\u5b9e\u9645\u4e0a\u5c31\u662funlink\u7cfb\u7edf\u8c03\u7528\u7684\u5c01\u88c5\u3002\u5982\u679c\u4e0d\u505aunlink\u64cd\u4f5c\uff0c\u90a3\u4e48\u6587\u4ef6\u4f1a\u4e00\u76f4\u5b58\u5728\u4e8e\/dev\/shm\u76ee\u5f55\u4e0b\uff0c\u4ee5\u4f9b\u5176\u5b83\u8fdb\u7a0b\u4f7f\u7528\u3002<\/li>\n<li>\u5173\u95ed\u5171\u4eab\u5185\u5b58\u63cf\u8ff0\u7b26\u76f4\u63a5\u4f7f\u7528close\u3002<\/li>\n<\/ol>\n<p>\u4ee5\u4e0a\u5c31\u662fPOSIX\u5171\u4eab\u5185\u5b58\u3002\u5176\u672c\u8d28\u4e0a\u5c31\u662f\u4e2atmpfs\u6587\u4ef6\u3002\u90a3\u4e48\u4ece\u8fd9\u4e2a\u89d2\u5ea6\u8bf4\uff0cmmap\u533f\u540d\u5171\u4eab\u5185\u5b58\u3001XSI\u5171\u4eab\u5185\u5b58\u548cPOSIX\u5171\u4eab\u5185\u5b58\u5728\u5185\u6838\u5b9e\u73b0\u672c\u8d28\u4e0a\u5176\u5b9e\u90fd\u662ftmpfs\u3002\u5982\u679c\u6211\u4eec\u53bb\u67e5\u770bPOSIX\u5171\u4eab\u5185\u5b58\u7684free\u7a7a\u95f4\u5360\u7528\u7684\u8bdd\uff0c\u7ed3\u679c\u5c06\u8ddfmmap\u548cXSI\u5171\u4eab\u5185\u5b58\u4e00\u6837\u5360\u7528shared\u548cbuff\/cache\uff0c\u6240\u4ee5\u6211\u4eec\u5c31\u4e0d\u518d\u505a\u8fd9\u4e2a\u6d4b\u8bd5\u4e86\u3002\u8fd9\u90e8\u5206\u5185\u5bb9\u5927\u5bb6\u4e5f\u53ef\u4ee5\u53c2\u8003\u300aLinux\u5185\u5b58\u4e2d\u7684Cache\u771f\u7684\u80fd\u88ab\u56de\u6536\u4e48\uff1f\u300b\u3002<\/p>\n<p>\u6839\u636e\u4ee5\u4e0a\u4f8b\u5b50\uff0c\u6211\u4eec\u6574\u7406\u4e00\u4e0bPOSIX\u5171\u4eab\u5185\u5b58\u7684\u4f7f\u7528\u76f8\u5173\u65b9\u6cd5\uff1a<\/p>\n<pre class=\"prism-token token  language-javascript\">#include <span class=\"token operator\">&lt;<\/span>sys<span class=\"token operator\">\/<\/span>mman<span class=\"token punctuation\">.<\/span>h<span class=\"token operator\">&gt;<\/span>\r\n#include <span class=\"token operator\">&lt;<\/span>sys<span class=\"token operator\">\/<\/span>stat<span class=\"token punctuation\">.<\/span>h<span class=\"token operator\">&gt;<\/span>        <span class=\"token comment\">\/* For mode constants *\/<\/span>\r\n#include <span class=\"token operator\">&lt;<\/span>fcntl<span class=\"token punctuation\">.<\/span>h<span class=\"token operator\">&gt;<\/span>           <span class=\"token comment\">\/* For O_* constants *\/<\/span>\r\n\r\nint <span class=\"token function\">shm_open<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">const<\/span> char <span class=\"token operator\">*<\/span>name<span class=\"token punctuation\">,<\/span> int oflag<span class=\"token punctuation\">,<\/span> mode_t mode<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n\r\nint <span class=\"token function\">shm_unlink<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">const<\/span> char <span class=\"token operator\">*<\/span>name<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/pre>\n<p>\u4f7f\u7528shm_open\u53ef\u4ee5\u521b\u5efa\u6216\u8005\u8bbf\u95ee\u4e00\u4e2a\u5df2\u7ecf\u521b\u5efa\u7684\u5171\u4eab\u5185\u5b58\u3002\u4e0a\u9762\u8bf4\u8fc7\uff0c\u5b9e\u9645\u4e0aPOSIX\u5171\u4eab\u5185\u5b58\u5c31\u662f\u5728\/dev\/shm\u76ee\u5f55\u4e2d\u7684\u7684\u4e00\u4e2atmpfs\u683c\u5f0f\u7684\u6587\u4ef6\uff0c\u6240\u4ee5shm_open\u65e0\u975e\u5c31\u662fopen\u7cfb\u7edf\u8c03\u7528\u7684\u5c01\u88c5\uff0c\u6240\u4ee5\u8d77\u51fd\u6570\u4f7f\u7528\u7684\u53c2\u6570\u51e0\u4e4e\u4e00\u6837\u3002\u5176\u8fd4\u56de\u7684\u4e5f\u662f\u4e00\u4e2a\u6807\u51c6\u7684\u6211\u5462\u95f4\u63cf\u8ff0\u7b26\u3002<\/p>\n<p>shm_unlink\u4e5f\u4e00\u6837\u662funlink\u8c03\u7528\u7684\u5c01\u88c5\uff0c\u7528\u6765\u5220\u9664\u6587\u4ef6\u540d\u548c\u6587\u4ef6\u7684\u6620\u5c04\u5173\u7cfb\u3002\u5728\u8fd9\u5c31\u80fd\u770b\u51faPOSIX\u5171\u4eab\u5185\u5b58\u548cXSI\u7684\u533a\u522b\u4e86\uff0c\u4e00\u4e2a\u662f\u4f7f\u7528\u6587\u4ef6\u540d\u4f5c\u4e3a\u5168\u5c40\u6807\u8bc6\uff0c\u53e6\u4e00\u4e2a\u662f\u4f7f\u7528key\u3002<\/p>\n<p>\u6620\u5c04\u5171\u4eab\u5185\u5b58\u5730\u5740\u4f7f\u7528mmap\uff0c\u89e3\u9664\u6620\u5c04\u4f7f\u7528munmap\u3002\u4f7f\u7528ftruncate\u8bbe\u7f6e\u5171\u4eab\u5185\u5b58\u5927\u5c0f\uff0c\u5b9e\u9645\u4e0a\u5c31\u662f\u5bf9tmpfs\u7684\u6587\u4ef6\u8fdb\u884c\u6307\u5b9a\u957f\u5ea6\u7684\u622a\u65ad\u3002\u4f7f\u7528fchmod\u3001fchown\u3001fstat\u7b49\u7cfb\u7edf\u8c03\u7528\u4fee\u6539\u548c\u67e5\u770b\u76f8\u5173\u5171\u4eab\u5185\u5b58\u7684\u5c5e\u6027\u3002close\u8c03\u7528\u5173\u95ed\u5171\u4eab\u5185\u5b58\u7684\u63cf\u8ff0\u7b26\u3002\u5b9e\u9645\u4e0a\uff0c\u8fd9\u90fd\u662f\u6807\u51c6\u7684\u6587\u4ef6\u64cd\u4f5c\u3002<\/p>\n<h2>\u6700\u540e<\/h2>\n<p>\u5e0c\u671b\u8fd9\u4e9b\u5185\u5bb9\u5bf9\u5927\u5bb6\u8fdb\u4e00\u6b65\u6df1\u5165\u4e86\u5171\u4eab\u5185\u5b58\u6709\u5e2e\u52a9\u3002\u5982\u679c\u6709\u76f8\u5173\u95ee\u9898\uff0c\u53ef\u4ee5\u5728\u6211\u7684\u5fae\u535a\u3001\u5fae\u4fe1\u6216\u8005\u535a\u5ba2\u4e0a\u8054\u7cfb\u6211\u3002<\/p>\n<p>\u5927\u5bb6\u597d\uff0c\u6211\u662fZorro\uff01<\/p>\n<p>\u5982\u679c\u4f60\u559c\u6b22\u672c\u6587\uff0c\u6b22\u8fce\u5728\u5fae\u535a\u4e0a\u641c\u7d22\u201corroz\u201d\u5173\u6ce8\u6211\uff0c\u5730\u5740\u662f\uff1a<a href=\"http:\/\/weibo.com\/orroz\" target=\"_blank\" rel=\"noopener\">http:\/\/weibo.com\/orroz<\/a><\/p>\n<p>\u5927\u5bb6\u4e5f\u53ef\u4ee5\u5728\u5fae\u4fe1\u4e0a\u641c\u7d22\uff1aLinux\u7cfb\u7edf\u6280\u672f \u5173\u6ce8\u6211\u7684\u516c\u4f17\u53f7\u3002<\/p>\n<p>\u6211\u7684\u6240\u6709\u6587\u7ae0\u90fd\u4f1a\u6c89\u6dc0\u5728\u6211\u7684\u4e2a\u4eba\u535a\u5ba2\u4e0a\uff0c\u5730\u5740\u662f\uff1a<a href=\"http:\/\/liwei.life.\/\" target=\"_blank\" rel=\"noopener\">http:\/\/liwei.life\u3002<\/a><\/p>\n<p>\u6b22\u8fce\u4f7f\u7528\u4ee5\u4e0a\u5404\u79cd\u65b9\u5f0f\u4e00\u8d77\u63a2\u8ba8\u5b66\u4e60\uff0c\u5171\u540c\u8fdb\u6b65\u3002<\/p>\n<\/div>\n<div class=\"col-article-source\">\n<p>\u539f\u521b\u58f0\u660e\uff0c\u672c\u6587\u7cfb\u4f5c\u8005\u6388\u6743\u4e91+\u793e\u533a-\u4e13\u680f\u53d1\u8868\uff0c\u672a\u7ecf\u8bb8\u53ef\uff0c\u4e0d\u5f97\u8f6c\u8f7d\u3002<\/p>\n<p>\u5982\u6709\u4fb5\u6743\uff0c\u8bf7\u8054\u7cfb\u00a0zhuanlan_guanli@qq.com\u00a0\u5220\u9664\u3002<\/p>\n<\/div>\n<div class=\"col-article-time\">\u7f16\u8f91\u4e8e\u00a0<span title=\"2017-07-27 09:49:16\">2017-07-27<\/span><\/div>\n","protected":false},"excerpt":{"rendered":"<p>Linux\u8fdb\u7a0b\u95f4\u901a\u4fe1\uff1a\u5171\u4eab\u5185\u5b58 \uff08\u4e0b\uff09 <\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"colormag_page_container_layout":"default_layout","colormag_page_sidebar_layout":"default_layout","footnotes":""},"categories":[],"tags":[118],"class_list":["post-1440","post","type-post","status-publish","format-standard","hentry","tag-02-"],"_links":{"self":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts\/1440","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/comments?post=1440"}],"version-history":[{"count":0,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts\/1440\/revisions"}],"wp:attachment":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/media?parent=1440"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/categories?post=1440"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/tags?post=1440"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}