{"id":800,"date":"2016-05-04T11:07:36","date_gmt":"2016-05-04T03:07:36","guid":{"rendered":"https:\/\/yanjingang.com\/blog\/?p=800"},"modified":"2018-12-17T20:26:16","modified_gmt":"2018-12-17T12:26:16","slug":"linux%e5%86%85%e5%ad%98%e4%b8%ad%e7%9a%84cache%e7%9c%9f%e7%9a%84%e8%83%bd%e8%a2%ab%e5%9b%9e%e6%94%b6%e4%b9%88%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/yanjingang.com\/blog\/?p=800","title":{"rendered":"Linux\u5185\u5b58\u4e2d\u7684Cache\u771f\u7684\u80fd\u88ab\u56de\u6536\u4e48\uff1f"},"content":{"rendered":"

\u5728Linux\u7cfb\u7edf\u4e2d\uff0c\u6211\u4eec\u7ecf\u5e38\u7528free\u547d\u4ee4\u6765\u67e5\u770b\u7cfb\u7edf\u5185\u5b58\u7684\u4f7f\u7528\u72b6\u6001\u3002\u5728\u4e00\u4e2aRHEL6\u7684\u7cfb\u7edf\u4e0a\uff0cfree\u547d\u4ee4\u7684\u663e\u793a\u5185\u5bb9\u5927\u6982\u662f\u8fd9\u6837\u4e00\u4e2a\u72b6\u6001\uff1a<\/p>\n

[root@tencent64 ~]# free\n             total       used       free     shared    buffers     cached\nMem:     132256952   72571772   59685180          0    1762632   53034704\n-\/+ buffers\/cache:   17774436  114482516\nSwap:      2101192        508    2100684\n<\/code><\/pre>\n
\u8fd9\u91cc\u7684\u9ed8\u8ba4\u663e\u793a\u5355\u4f4d\u662fkb\uff0c\u6211\u7684\u670d\u52a1\u5668\u662f128G\u5185\u5b58\uff0c\u6240\u4ee5\u6570\u5b57\u663e\u5f97\u6bd4\u8f83\u5927\u3002\u8fd9\u4e2a\u547d\u4ee4\u51e0\u4e4e\u662f\u6bcf\u4e00\u4e2a\u4f7f\u7528\u8fc7Linux\u7684\u4eba\u5fc5\u4f1a\u7684\u547d\u4ee4\uff0c\u4f46\u8d8a\u662f\u8fd9\u6837\u7684\u547d\u4ee4\uff0c\u4f3c\u4e4e\u771f\u6b63\u660e\u767d\u7684\u4eba\u8d8a\u5c11\uff08\u6211\u662f\u8bf4\u6bd4\u4f8b\u8d8a\u5c11\uff09\u3002\u4e00\u822c\u60c5\u51b5\u4e0b\uff0c\u5bf9\u6b64\u547d\u4ee4\u8f93\u51fa\u7684\u7406\u89e3\u53ef\u4ee5\u5206\u8fd9\u51e0\u4e2a\u5c42\u6b21\uff1a<\/p>\n
    \n
  1. \u4e0d\u4e86\u89e3\u3002\u8fd9\u6837\u7684\u4eba\u7684\u7b2c\u4e00\u53cd\u5e94\u662f\uff1a\u5929\u554a\uff0c\u5185\u5b58\u7528\u4e86\u597d\u591a\uff0c70\u4e2a\u591aG\uff0c\u53ef\u662f\u6211\u51e0\u4e4e\u6ca1\u6709\u8fd0\u884c\u4ec0\u4e48\u5927\u7a0b\u5e8f\u554a\uff1f\u4e3a\u4ec0\u4e48\u4f1a\u8fd9\u6837\uff1fLinux\u597d\u5360\u5185\u5b58\uff01<\/li>\n
  2. \u81ea\u4ee5\u4e3a\u5f88\u4e86\u89e3\u3002\u8fd9\u6837\u7684\u4eba\u4e00\u822c\u8bc4\u4f30\u8fc7\u4f1a\u8bf4\uff1a\u55ef\uff0c\u6839\u636e\u6211\u4e13\u4e1a\u7684\u773c\u5149\u770b\u7684\u51fa\u6765\uff0c\u5185\u5b58\u624d\u7528\u4e8617G\u5de6\u53f3\uff0c\u8fd8\u6709\u5f88\u591a\u5269\u4f59\u5185\u5b58\u53ef\u7528\u3002buffers\/cache\u5360\u7528\u7684\u8f83\u591a\uff0c\u8bf4\u660e\u7cfb\u7edf\u4e2d\u6709\u8fdb\u7a0b\u66fe\u7ecf\u8bfb\u5199\u8fc7\u6587\u4ef6\uff0c\u4f46\u662f\u4e0d\u8981\u7d27\uff0c\u8fd9\u90e8\u5206\u5185\u5b58\u662f\u5f53\u7a7a\u95f2\u6765\u7528\u7684\u3002<\/li>\n
  3. \u771f\u7684\u5f88\u4e86\u89e3\u3002\u8fd9\u79cd\u4eba\u7684\u53cd\u5e94\u53cd\u800c\u8ba9\u4eba\u611f\u89c9\u6700\u4e0d\u61c2Linux\uff0c\u4ed6\u4eec\u7684\u53cd\u5e94\u662f\uff1afree\u663e\u793a\u7684\u662f\u8fd9\u6837\uff0c\u597d\u5427\u6211\u77e5\u9053\u4e86\u3002\u795e\u9a6c\uff1f\u4f60\u95ee\u6211\u8fd9\u4e9b\u5185\u5b58\u591f\u4e0d\u591f\uff0c\u6211\u5f53\u7136\u4e0d\u77e5\u9053\u5566\uff01\u6211\u7279\u4e48\u600e\u4e48\u77e5\u9053\u4f60\u7a0b\u5e8f\u600e\u4e48\u5199\u7684\uff1f<\/li>\n<\/ol>\n
    \u6839\u636e\u76ee\u524d\u7f51\u7edc\u4e0a\u6280\u672f\u6587\u6863\u7684\u5185\u5bb9\uff0c\u6211\u76f8\u4fe1\u7edd\u5927\u591a\u6570\u4e86\u89e3\u4e00\u70b9Linux\u7684\u4eba\u5e94\u8be5\u5904\u5728\u7b2c\u4e8c\u79cd\u5c42\u6b21\u3002\u5927\u5bb6\u666e\u904d\u8ba4\u4e3a\uff0cbuffers\u548ccached\u6240\u5360\u7528\u7684\u5185\u5b58\u7a7a\u95f4\u662f\u53ef\u4ee5\u5728\u5185\u5b58\u538b\u529b\u8f83\u5927\u7684\u65f6\u5019\u88ab\u91ca\u653e\u5f53\u505a\u7a7a\u95f2\u7a7a\u95f4\u7528\u7684\u3002\u4f46\u771f\u7684\u662f\u8fd9\u6837\u4e48\uff1f\u5728\u8bba\u8bc1\u8fd9\u4e2a\u9898\u76ee\u4e4b\u524d\uff0c\u6211\u4eec\u5148\u7b80\u8981\u4ecb\u7ecd\u4e00\u4e0bbuffers\u548ccached\u662f\u4ec0\u4e48\u610f\u601d\uff1a<\/p>\n
    \u4ec0\u4e48\u662fbuffer\/cache\uff1f<\/h2>\n
    buffer\u548ccache\u662f\u4e24\u4e2a\u5728\u8ba1\u7b97\u673a\u6280\u672f\u4e2d\u88ab\u7528\u6ee5\u7684\u540d\u8bcd\uff0c\u653e\u5728\u4e0d\u901a\u8bed\u5883\u4e0b\u4f1a\u6709\u4e0d\u540c\u7684\u610f\u4e49\u3002\u5728Linux\u7684\u5185\u5b58\u7ba1\u7406\u4e2d\uff0c\u8fd9\u91cc\u7684buffer\u6307Linux\u5185\u5b58\u7684\uff1aBuffer cache\u3002\u8fd9\u91cc\u7684cache\u6307Linux\u5185\u5b58\u4e2d\u7684\uff1aPage cache\u3002\u7ffb\u8bd1\u6210\u4e2d\u6587\u53ef\u4ee5\u53eb\u505a\u7f13\u51b2\u533a\u7f13\u5b58\u548c\u9875\u9762\u7f13\u5b58\u3002\u5728\u5386\u53f2\u4e0a\uff0c\u5b83\u4eec\u4e00\u4e2a\uff08buffer\uff09\u88ab\u7528\u6765\u5f53\u6210\u5bf9io\u8bbe\u5907\u5199\u7684\u7f13\u5b58\uff0c\u800c\u53e6\u4e00\u4e2a\uff08cache\uff09\u88ab\u7528\u6765\u5f53\u4f5c\u5bf9io\u8bbe\u5907\u7684\u8bfb\u7f13\u5b58\uff0c\u8fd9\u91cc\u7684io\u8bbe\u5907\uff0c\u4e3b\u8981\u6307\u7684\u662f\u5757\u8bbe\u5907\u6587\u4ef6\u548c\u6587\u4ef6\u7cfb\u7edf\u4e0a\u7684\u666e\u901a\u6587\u4ef6\u3002\u4f46\u662f\u73b0\u5728\uff0c\u5b83\u4eec\u7684\u610f\u4e49\u5df2\u7ecf\u4e0d\u4e00\u6837\u4e86\u3002<\/strong>\u5728\u5f53\u524d\u7684\u5185\u6838\u4e2d\uff0cpage cache\u987e\u540d\u601d\u4e49\u5c31\u662f\u9488\u5bf9\u5185\u5b58\u9875\u7684\u7f13\u5b58\uff0c\u8bf4\u767d\u4e86\u5c31\u662f\uff0c\u5982\u679c\u6709\u5185\u5b58\u662f\u4ee5page\u8fdb\u884c\u5206\u914d\u7ba1\u7406\u7684\uff0c\u90fd\u53ef\u4ee5\u4f7f\u7528page cache\u4f5c\u4e3a\u5176\u7f13\u5b58\u6765\u7ba1\u7406\u4f7f\u7528\u3002\u5f53\u7136\uff0c\u4e0d\u662f\u6240\u6709\u7684\u5185\u5b58\u90fd\u662f\u4ee5\u9875\uff08page\uff09\u8fdb\u884c\u7ba1\u7406\u7684\uff0c\u4e5f\u6709\u5f88\u591a\u662f\u9488\u5bf9\u5757\uff08block\uff09\u8fdb\u884c\u7ba1\u7406\u7684\uff0c\u8fd9\u90e8\u5206\u5185\u5b58\u4f7f\u7528\u5982\u679c\u8981\u7528\u5230cache\u529f\u80fd\uff0c\u5219\u90fd\u96c6\u4e2d\u5230buffer cache\u4e2d\u6765\u4f7f\u7528\u3002\uff08\u4ece\u8fd9\u4e2a\u89d2\u5ea6\u51fa\u53d1\uff0c\u662f\u4e0d\u662fbuffer cache\u6539\u540d\u53eb\u505ablock cache\u66f4\u597d\uff1f\uff09\u7136\u800c\uff0c\u4e5f\u4e0d\u662f\u6240\u6709\u5757\uff08block\uff09\u90fd\u6709\u56fa\u5b9a\u957f\u5ea6\uff0c\u7cfb\u7edf\u4e0a\u5757\u7684\u957f\u5ea6\u4e3b\u8981\u662f\u6839\u636e\u6240\u4f7f\u7528\u7684\u5757\u8bbe\u5907\u51b3\u5b9a\u7684\uff0c\u800c\u9875\u957f\u5ea6\u5728X86\u4e0a\u65e0\u8bba\u662f32\u4f4d\u8fd8\u662f64\u4f4d\u90fd\u662f4k\u3002<\/p>\n
    \u660e\u767d\u4e86\u8fd9\u4e24\u5957\u7f13\u5b58\u7cfb\u7edf\u7684\u533a\u522b\uff0c\u5c31\u53ef\u4ee5\u7406\u89e3\u5b83\u4eec\u7a76\u7adf\u90fd\u53ef\u4ee5\u7528\u6765\u505a\u4ec0\u4e48\u4e86\u3002<\/p>\n
    \u4ec0\u4e48\u662fpage cache<\/strong><\/p>\n
    Page cache\u4e3b\u8981\u7528\u6765\u4f5c\u4e3a\u6587\u4ef6\u7cfb\u7edf\u4e0a\u7684\u6587\u4ef6\u6570\u636e\u7684\u7f13\u5b58\u6765\u7528\uff0c\u5c24\u5176\u662f\u9488\u5bf9\u5f53\u8fdb\u7a0b\u5bf9\u6587\u4ef6\u6709read\uff0fwrite\u64cd\u4f5c\u7684\u65f6\u5019\u3002\u5982\u679c\u4f60\u4ed4\u7ec6\u60f3\u60f3\u7684\u8bdd\uff0c\u4f5c\u4e3a\u53ef\u4ee5\u6620\u5c04\u6587\u4ef6\u5230\u5185\u5b58\u7684\u7cfb\u7edf\u8c03\u7528\uff1ammap\u662f\u4e0d\u662f\u5f88\u81ea\u7136\u7684\u4e5f\u5e94\u8be5\u7528\u5230page cache\uff1f\u5728\u5f53\u524d\u7684\u7cfb\u7edf\u5b9e\u73b0\u91cc\uff0cpage cache\u4e5f\u88ab\u4f5c\u4e3a\u5176\u5b83\u6587\u4ef6\u7c7b\u578b\u7684\u7f13\u5b58\u8bbe\u5907\u6765\u7528\uff0c\u6240\u4ee5\u4e8b\u5b9e\u4e0apage cache\u4e5f\u8d1f\u8d23\u4e86\u5927\u90e8\u5206\u7684\u5757\u8bbe\u5907\u6587\u4ef6\u7684\u7f13\u5b58\u5de5\u4f5c\u3002<\/p>\n
    \u4ec0\u4e48\u662fbuffer cache<\/strong><\/p>\n
    Buffer cache\u5219\u4e3b\u8981\u662f\u8bbe\u8ba1\u7528\u6765\u5728\u7cfb\u7edf\u5bf9\u5757\u8bbe\u5907\u8fdb\u884c\u8bfb\u5199\u7684\u65f6\u5019\uff0c\u5bf9\u5757\u8fdb\u884c\u6570\u636e\u7f13\u5b58\u7684\u7cfb\u7edf\u6765\u4f7f\u7528\u3002\u8fd9\u610f\u5473\u7740\u67d0\u4e9b\u5bf9\u5757\u7684\u64cd\u4f5c\u4f1a\u4f7f\u7528buffer cache\u8fdb\u884c\u7f13\u5b58\uff0c\u6bd4\u5982\u6211\u4eec\u5728\u683c\u5f0f\u5316\u6587\u4ef6\u7cfb\u7edf\u7684\u65f6\u5019\u3002\u4e00\u822c\u60c5\u51b5\u4e0b\u4e24\u4e2a\u7f13\u5b58\u7cfb\u7edf\u662f\u4e00\u8d77\u914d\u5408\u4f7f\u7528\u7684\uff0c\u6bd4\u5982\u5f53\u6211\u4eec\u5bf9\u4e00\u4e2a\u6587\u4ef6\u8fdb\u884c\u5199\u64cd\u4f5c\u7684\u65f6\u5019\uff0cpage cache\u7684\u5185\u5bb9\u4f1a\u88ab\u6539\u53d8\uff0c\u800cbuffer cache\u5219\u53ef\u4ee5\u7528\u6765\u5c06page\u6807\u8bb0\u4e3a\u4e0d\u540c\u7684\u7f13\u51b2\u533a\uff0c\u5e76\u8bb0\u5f55\u662f\u54ea\u4e00\u4e2a\u7f13\u51b2\u533a\u88ab\u4fee\u6539\u4e86\u3002\u8fd9\u6837\uff0c\u5185\u6838\u5728\u540e\u7eed\u6267\u884c\u810f\u6570\u636e\u7684\u56de\u5199\uff08writeback\uff09\u65f6\uff0c\u5c31\u4e0d\u7528\u5c06\u6574\u4e2apage\u5199\u56de\uff0c\u800c\u53ea\u9700\u8981\u5199\u56de\u4fee\u6539\u7684\u90e8\u5206\u5373\u53ef\u3002<\/p>\n
    \u5982\u4f55\u56de\u6536cache\uff1f<\/h2>\n
    Linux\u5185\u6838\u4f1a\u5728\u5185\u5b58\u5c06\u8981\u8017\u5c3d\u7684\u65f6\u5019\uff0c\u89e6\u53d1\u5185\u5b58\u56de\u6536\u7684\u5de5\u4f5c\uff0c\u4ee5\u4fbf\u91ca\u653e\u51fa\u5185\u5b58\u7ed9\u6025\u9700\u5185\u5b58\u7684\u8fdb\u7a0b\u4f7f\u7528\u3002\u4e00\u822c\u60c5\u51b5\u4e0b\uff0c\u8fd9\u4e2a\u64cd\u4f5c\u4e2d\u4e3b\u8981\u7684\u5185\u5b58\u91ca\u653e\u90fd\u6765\u81ea\u4e8e\u5bf9buffer\uff0fcache\u7684\u91ca\u653e\u3002\u5c24\u5176\u662f\u88ab\u4f7f\u7528\u66f4\u591a\u7684cache\u7a7a\u95f4\u3002\u65e2\u7136\u5b83\u4e3b\u8981\u7528\u6765\u505a\u7f13\u5b58\uff0c\u53ea\u662f\u5728\u5185\u5b58\u591f\u7528\u7684\u65f6\u5019\u52a0\u5feb\u8fdb\u7a0b\u5bf9\u6587\u4ef6\u7684\u8bfb\u5199\u901f\u5ea6\uff0c\u90a3\u4e48\u5728\u5185\u5b58\u538b\u529b\u8f83\u5927\u7684\u60c5\u51b5\u4e0b\uff0c\u5f53\u7136\u6709\u5fc5\u8981\u6e05\u7a7a\u91ca\u653ecache\uff0c\u4f5c\u4e3afree\u7a7a\u95f4\u5206\u7ed9\u76f8\u5173\u8fdb\u7a0b\u4f7f\u7528\u3002\u6240\u4ee5\u4e00\u822c\u60c5\u51b5\u4e0b\uff0c\u6211\u4eec\u8ba4\u4e3abuffer\/cache\u7a7a\u95f4\u53ef\u4ee5\u88ab\u91ca\u653e\uff0c\u8fd9\u4e2a\u7406\u89e3\u662f\u6b63\u786e\u7684\u3002<\/p>\n
    \u4f46\u662f\u8fd9\u79cd\u6e05\u7f13\u5b58\u7684\u5de5\u4f5c\u4e5f\u5e76\u4e0d\u662f\u6ca1\u6709\u6210\u672c\u3002\u7406\u89e3cache\u662f\u5e72\u4ec0\u4e48\u7684\u5c31\u53ef\u4ee5\u660e\u767d\u6e05\u7f13\u5b58\u5fc5\u987b\u4fdd\u8bc1cache\u4e2d\u7684\u6570\u636e\u8ddf\u5bf9\u5e94\u6587\u4ef6\u4e2d\u7684\u6570\u636e\u4e00\u81f4\uff0c\u624d\u80fd\u5bf9cache\u8fdb\u884c\u91ca\u653e\u3002\u6240\u4ee5\u4f34\u968f\u7740cache\u6e05\u9664\u7684\u884c\u4e3a\u7684\uff0c\u4e00\u822c\u90fd\u662f\u7cfb\u7edfIO\u98d9\u9ad8\u3002<\/strong>\u56e0\u4e3a\u5185\u6838\u8981\u5bf9\u6bd4cache\u4e2d\u7684\u6570\u636e\u548c\u5bf9\u5e94\u786c\u76d8\u6587\u4ef6\u4e0a\u7684\u6570\u636e\u662f\u5426\u4e00\u81f4\uff0c\u5982\u679c\u4e0d\u4e00\u81f4\u9700\u8981\u5199\u56de\uff0c\u4e4b\u540e\u624d\u80fd\u56de\u6536\u3002<\/p>\n
    \u5728\u7cfb\u7edf\u4e2d\u9664\u4e86\u5185\u5b58\u5c06\u88ab\u8017\u5c3d\u7684\u65f6\u5019\u53ef\u4ee5\u6e05\u7f13\u5b58\u4ee5\u5916\uff0c\u6211\u4eec\u8fd8\u53ef\u4ee5\u4f7f\u7528\u4e0b\u9762\u8fd9\u4e2a\u6587\u4ef6\u6765\u4eba\u5de5\u89e6\u53d1\u7f13\u5b58\u6e05\u9664\u7684\u64cd\u4f5c\uff1a<\/p>\n
    [root@tencent64 ~]# cat \/proc\/sys\/vm\/drop_caches \n1\n<\/code><\/pre>\n
    \u65b9\u6cd5\u662f\uff1a<\/p>\n
    echo 1 > \/proc\/sys\/vm\/drop_caches\n<\/code><\/pre>\n
    \u5f53\u7136\uff0c\u8fd9\u4e2a\u6587\u4ef6\u53ef\u4ee5\u8bbe\u7f6e\u7684\u503c\u5206\u522b\u4e3a1\u30012\u30013\u3002\u5b83\u4eec\u6240\u8868\u793a\u7684\u542b\u4e49\u4e3a\uff1a
    \necho 1 > \/proc\/sys\/vm\/drop_caches<\/strong>:\u8868\u793a\u6e05\u9664pagecache\u3002<\/p>\n
    echo 2 > \/proc\/sys\/vm\/drop_caches<\/strong>:\u8868\u793a\u6e05\u9664\u56de\u6536slab\u5206\u914d\u5668\u4e2d\u7684\u5bf9\u8c61\uff08\u5305\u62ec\u76ee\u5f55\u9879\u7f13\u5b58\u548cinode\u7f13\u5b58\uff09\u3002slab\u5206\u914d\u5668\u662f\u5185\u6838\u4e2d\u7ba1\u7406\u5185\u5b58\u7684\u4e00\u79cd\u673a\u5236\uff0c\u5176\u4e2d\u5f88\u591a\u7f13\u5b58\u6570\u636e\u5b9e\u73b0\u90fd\u662f\u7528\u7684pagecache\u3002<\/p>\n
    echo 3 > \/proc\/sys\/vm\/drop_caches<\/strong>:\u8868\u793a\u6e05\u9664pagecache\u548cslab\u5206\u914d\u5668\u4e2d\u7684\u7f13\u5b58\u5bf9\u8c61\u3002<\/p>\n
    cache\u90fd\u80fd\u88ab\u56de\u6536\u4e48\uff1f<\/h2>\n
    \u6211\u4eec\u5206\u6790\u4e86cache\u80fd\u88ab\u56de\u6536\u7684\u60c5\u51b5\uff0c\u90a3\u4e48\u6709\u6ca1\u6709\u4e0d\u80fd\u88ab\u56de\u6536\u7684cache\u5462\uff1f\u5f53\u7136\u6709\u3002\u6211\u4eec\u5148\u6765\u770b\u7b2c\u4e00\u79cd\u60c5\u51b5\uff1a<\/p>\n
    tmpfs<\/h3>\n
    \u5927\u5bb6\u77e5\u9053Linux\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\u5f53\u7136\uff0c\u6211\u4eec\u4e5f\u53ef\u4ee5\u624b\u5de5\u521b\u5efa\u4e00\u4e2a\u81ea\u5df1\u7684tmpfs\uff0c\u65b9\u6cd5\u5982\u4e0b\uff1a<\/p>\n
    [root@tencent64 ~]# mkdir \/tmp\/tmpfs\n[root@tencent64 ~]# mount -t tmpfs -o size=20G none \/tmp\/tmpfs\/\n\n[root@tencent64 ~]# df\nFilesystem           1K-blocks      Used Available Use% Mounted on\n\/dev\/sda1             10325000   3529604   6270916  37% \/\n\/dev\/sda3             20646064   9595940  10001360  49% \/usr\/local\n\/dev\/mapper\/vg-data  103212320  26244284  71725156  27% \/data\ntmpfs                 66128476  14709004  51419472  23% \/dev\/shm\nnone                  20971520         0  20971520   0% \/tmp\/tmpfs\n<\/code><\/pre>\n
    \u4e8e\u662f\u6211\u4eec\u5c31\u521b\u5efa\u4e86\u4e00\u4e2a\u65b0\u7684tmpfs\uff0c\u7a7a\u95f4\u662f20G\uff0c\u6211\u4eec\u53ef\u4ee5\u5728\/tmp\/tmpfs\u4e2d\u521b\u5efa\u4e00\u4e2a20G\u4ee5\u5185\u7684\u6587\u4ef6\u3002\u5982\u679c\u6211\u4eec\u521b\u5efa\u7684\u6587\u4ef6\u5b9e\u9645\u5360\u7528\u7684\u7a7a\u95f4\u662f\u5185\u5b58\u7684\u8bdd\uff0c\u90a3\u4e48\u8fd9\u4e9b\u6570\u636e\u5e94\u8be5\u5360\u7528\u5185\u5b58\u7a7a\u95f4\u7684\u4ec0\u4e48\u90e8\u5206\u5462\uff1f\u6839\u636epagecache\u7684\u5b9e\u73b0\u529f\u80fd\u53ef\u4ee5\u7406\u89e3\uff0c\u65e2\u7136\u662f\u67d0\u79cd\u6587\u4ef6\u7cfb\u7edf\uff0c\u90a3\u4e48\u81ea\u7136\u8be5\u4f7f\u7528pagecache\u7684\u7a7a\u95f4\u6765\u7ba1\u7406\u3002\u6211\u4eec\u8bd5\u8bd5\u662f\u4e0d\u662f\u8fd9\u6837\uff1f<\/p>\n
    [root@tencent64 ~]# free -g\n             total       used       free     shared    buffers     cached\nMem:           126         36         89          0          1         19\n-\/+ buffers\/cache:         15        111\nSwap:            2          0          2\n[root@tencent64 ~]# dd if=\/dev\/zero of=\/tmp\/tmpfs\/testfile bs=1G count=13\n13+0 records in\n13+0 records out\n13958643712 bytes (14 GB) copied, 9.49858 s, 1.5 GB\/s\n[root@tencent64 ~]# \n[root@tencent64 ~]# free -g\n             total       used       free     shared    buffers     cached\nMem:           126         49         76          0          1         32\n-\/+ buffers\/cache:         15        110\nSwap:            2          0          2\n<\/code><\/pre>\n
    \u6211\u4eec\u5728tmpfs\u76ee\u5f55\u4e0b\u521b\u5efa\u4e86\u4e00\u4e2a13G\u7684\u6587\u4ef6\uff0c\u5e76\u901a\u8fc7\u524d\u540efree\u547d\u4ee4\u7684\u5bf9\u6bd4\u53d1\u73b0\uff0ccached\u589e\u957f\u4e8613G\uff0c\u8bf4\u660e\u8fd9\u4e2a\u6587\u4ef6\u786e\u5b9e\u653e\u5728\u4e86\u5185\u5b58\u91cc\u5e76\u4e14\u5185\u6838\u4f7f\u7528\u7684\u662fcache\u4f5c\u4e3a\u5b58\u50a8\u3002\u518d\u770b\u770b\u6211\u4eec\u5173\u5fc3\u7684\u6307\u6807\uff1a -\/+ buffers\/cache\u90a3\u4e00\u884c\u3002\u6211\u4eec\u53d1\u73b0\uff0c\u5728\u8fd9\u79cd\u60c5\u51b5\u4e0bfree\u547d\u4ee4\u4ecd\u7136\u63d0\u793a\u6211\u4eec\u6709110G\u5185\u5b58\u53ef\u7528\uff0c\u4f46\u662f\u771f\u7684\u6709\u8fd9\u4e48\u591a\u4e48\uff1f\u6211\u4eec\u53ef\u4ee5\u4eba\u5de5\u89e6\u53d1\u5185\u5b58\u56de\u6536\u770b\u770b\u73b0\u5728\u5230\u5e95\u80fd\u56de\u6536\u591a\u5c11\u5185\u5b58\uff1a<\/p>\n
    [root@tencent64 ~]# echo 3 > \/proc\/sys\/vm\/drop_caches\n[root@tencent64 ~]# free -g\n             total       used       free     shared    buffers     cached\nMem:           126         43         82          0          0         29\n-\/+ buffers\/cache:         14        111\nSwap:            2          0          2\n<\/code><\/pre>\n
    \u53ef\u4ee5\u770b\u5230\uff0ccached\u5360\u7528\u7684\u7a7a\u95f4\u5e76\u6ca1\u6709\u50cf\u6211\u4eec\u60f3\u8c61\u7684\u90a3\u6837\u5b8c\u5168\u88ab\u91ca\u653e\uff0c\u5176\u4e2d13G\u7684\u7a7a\u95f4\u4ecd\u7136\u88ab\/tmp\/tmpfs\u4e2d\u7684\u6587\u4ef6\u5360\u7528\u7684\u3002\u5f53\u7136\uff0c\u6211\u7684\u7cfb\u7edf\u4e2d\u8fd8\u6709\u5176\u4ed6\u4e0d\u53ef\u91ca\u653e\u7684cache\u5360\u7528\u7740\u5176\u4f5916G\u5185\u5b58\u7a7a\u95f4\u3002\u90a3\u4e48tmpfs\u5360\u7528\u7684cache\u7a7a\u95f4\u4ec0\u4e48\u65f6\u5019\u4f1a\u88ab\u91ca\u653e\u5462\uff1f\u662f\u5728\u5176\u6587\u4ef6\u88ab\u5220\u9664\u7684\u65f6\u5019.\u5982\u679c\u4e0d\u5220\u9664\u6587\u4ef6\uff0c\u65e0\u8bba\u5185\u5b58\u8017\u5c3d\u5230\u4ec0\u4e48\u7a0b\u5ea6\uff0c\u5185\u6838\u90fd\u4e0d\u4f1a\u81ea\u52a8\u5e2e\u4f60\u628atmpfs\u4e2d\u7684\u6587\u4ef6\u5220\u9664\u6765\u91ca\u653ecache\u7a7a\u95f4\u3002<\/p>\n
    [root@tencent64 ~]# rm \/tmp\/tmpfs\/testfile \n[root@tencent64 ~]# free -g\n             total       used       free     shared    buffers     cached\nMem:           126         30         95          0          0         16\n-\/+ buffers\/cache:         14        111\nSwap:            2          0          2\n<\/code><\/pre>\n
    \u8fd9\u662f\u6211\u4eec\u5206\u6790\u7684\u7b2c\u4e00\u79cdcache\u4e0d\u80fd\u88ab\u56de\u6536\u7684\u60c5\u51b5\u3002\u8fd8\u6709\u5176\u4ed6\u60c5\u51b5\uff0c\u6bd4\u5982\uff1a<\/p>\n
    \u5171\u4eab\u5185\u5b58<\/h3>\n
    \u5171\u4eab\u5185\u5b58\u662f\u7cfb\u7edf\u63d0\u4f9b\u7ed9\u6211\u4eec\u7684\u4e00\u79cd\u5e38\u7528\u7684\u8fdb\u7a0b\u95f4\u901a\u4fe1\uff08IPC\uff09\u65b9\u5f0f\uff0c\u4f46\u662f\u8fd9\u79cd\u901a\u4fe1\u65b9\u5f0f\u4e0d\u80fd\u5728shell\u4e2d\u7533\u8bf7\u548c\u4f7f\u7528\uff0c\u6240\u4ee5\u6211\u4eec\u9700\u8981\u4e00\u4e2a\u7b80\u5355\u7684\u6d4b\u8bd5\u7a0b\u5e8f\uff0c\u4ee3\u7801\u5982\u4e0b\uff1a<\/p>\n
    [root@tencent64 ~]# cat shm.c \n\n#include <stdio.h>\n#include <stdlib.h>\n#include <unistd.h>\n#include <sys\/ipc.h>\n#include <sys\/shm.h>\n#include <string.h>\n\n#define MEMSIZE 2048*1024*1023\n\nint\nmain()\n{\n    int shmid;\n    char *ptr;\n    pid_t pid;\n    struct shmid_ds buf;\n    int ret;\n\n    shmid = shmget(IPC_PRIVATE, MEMSIZE, 0600);\n    if (shmid<0) {\n        perror(\"shmget()\");\n        exit(1);\n    }\n\n    ret = shmctl(shmid, IPC_STAT, &buf);\n    if (ret < 0) {\n        perror(\"shmctl()\");\n        exit(1);\n    }\n\n    printf(\"shmid: %d\\n\", shmid);\n    printf(\"shmsize: %d\\n\", buf.shm_segsz);\n\n    buf.shm_segsz *= 2;\n\n    ret = shmctl(shmid, IPC_SET, &buf);\n    if (ret < 0) {\n        perror(\"shmctl()\");\n        exit(1);\n    }\n\n    ret = shmctl(shmid, IPC_SET, &buf);\n    if (ret < 0) {\n        perror(\"shmctl()\");\n        exit(1);\n    }\n\n    printf(\"shmid: %d\\n\", shmid);\n    printf(\"shmsize: %d\\n\", buf.shm_segsz);\n\n\n    pid = fork();\n    if (pid<0) {\n        perror(\"fork()\");\n        exit(1);\n    }\n    if (pid==0) {\n        ptr = shmat(shmid, NULL, 0);\n        if (ptr==(void*)-1) {\n            perror(\"shmat()\");\n            exit(1);\n        }\n        bzero(ptr, MEMSIZE);\n        strcpy(ptr, \"Hello!\");\n        exit(0);\n    } else {\n        wait(NULL);\n        ptr = shmat(shmid, NULL, 0);\n        if (ptr==(void*)-1) {\n            perror(\"shmat()\");\n            exit(1);\n        }\n        puts(ptr);\n        exit(0);\n    }\n}\n<\/code><\/pre>\n
    \u7a0b\u5e8f\u529f\u80fd\u5f88\u7b80\u5355\uff0c\u5c31\u662f\u7533\u8bf7\u4e00\u6bb5\u4e0d\u52302G\u5171\u4eab\u5185\u5b58\uff0c\u7136\u540e\u6253\u5f00\u4e00\u4e2a\u5b50\u8fdb\u7a0b\u5bf9\u8fd9\u6bb5\u5171\u4eab\u5185\u5b58\u505a\u4e00\u4e2a\u521d\u59cb\u5316\u64cd\u4f5c\uff0c\u7236\u8fdb\u7a0b\u7b49\u5b50\u8fdb\u7a0b\u521d\u59cb\u5316\u5b8c\u4e4b\u540e\u8f93\u51fa\u4e00\u4e0b\u5171\u4eab\u5185\u5b58\u7684\u5185\u5bb9\uff0c\u7136\u540e\u9000\u51fa\u3002\u4f46\u662f\u9000\u51fa\u4e4b\u524d\u5e76\u6ca1\u6709\u5220\u9664\u8fd9\u6bb5\u5171\u4eab\u5185\u5b58\u3002\u6211\u4eec\u6765\u770b\u770b\u8fd9\u4e2a\u7a0b\u5e8f\u6267\u884c\u524d\u540e\u7684\u5185\u5b58\u4f7f\u7528\uff1a<\/p>\n
    [root@tencent64 ~]# free -g\n             total       used       free     shared    buffers     cached\nMem:           126         30         95          0          0         16\n-\/+ buffers\/cache:         14        111\nSwap:            2          0          2\n[root@tencent64 ~]# .\/shm \nshmid: 294918\nshmsize: 2145386496\nshmid: 294918\nshmsize: -4194304\nHello!\n[root@tencent64 ~]# free -g\n             total       used       free     shared    buffers     cached\nMem:           126         32         93          0          0         18\n-\/+ buffers\/cache:         14        111\nSwap:            2          0          2\n<\/code><\/pre>\n
    cached\u7a7a\u95f4\u753116G\u6da8\u5230\u4e8618G\u3002\u90a3\u4e48\u8fd9\u6bb5cache\u80fd\u88ab\u56de\u6536\u4e48\uff1f\u7ee7\u7eed\u6d4b\u8bd5\uff1a<\/p>\n
    [root@tencent64 ~]# echo 3 > \/proc\/sys\/vm\/drop_caches\n[root@tencent64 ~]# free -g\n             total       used       free     shared    buffers     cached\nMem:           126         32         93          0          0         18\n-\/+ buffers\/cache:         14        111\nSwap:            2          0          2\n<\/code><\/pre>\n
    \u7ed3\u679c\u662f\u4ecd\u7136\u4e0d\u53ef\u56de\u6536\u3002\u5927\u5bb6\u53ef\u4ee5\u89c2\u5bdf\u5230\uff0c\u8fd9\u6bb5\u5171\u4eab\u5185\u5b58\u5373\u4f7f\u6ca1\u4eba\u4f7f\u7528\uff0c\u4ecd\u7136\u4f1a\u957f\u671f\u5b58\u653e\u5728cache\u4e2d\uff0c\u76f4\u5230\u5176\u88ab\u5220\u9664\u3002\u5220\u9664\u65b9\u6cd5\u6709\u4e24\u79cd\uff0c\u4e00\u79cd\u662f\u7a0b\u5e8f\u4e2d\u4f7f\u7528shmctl()\u53bbIPC_RMID\uff0c\u53e6\u4e00\u79cd\u662f\u4f7f\u7528ipcrm\u547d\u4ee4\u3002\u6211\u4eec\u6765\u5220\u9664\u8bd5\u8bd5\uff1a<\/p>\n
    [root@tencent64 ~]# ipcs -m\n\n------ Shared Memory Segments --------\nkey        shmid      owner      perms      bytes      nattch     status      \n0x00005feb 0          root       666        12000      4                       \n0x00005fe7 32769      root       666        524288     2                       \n0x00005fe8 65538      root       666        2097152    2                       \n0x00038c0e 131075     root       777        2072       1                       \n0x00038c14 163844     root       777        5603392    0                       \n0x00038c09 196613     root       777        221248     0                       \n0x00000000 294918     root       600        2145386496 0                       \n\n[root@tencent64 ~]# ipcrm -m 294918\n[root@tencent64 ~]# ipcs -m\n\n------ Shared Memory Segments --------\nkey        shmid      owner      perms      bytes      nattch     status      \n0x00005feb 0          root       666        12000      4                       \n0x00005fe7 32769      root       666        524288     2                       \n0x00005fe8 65538      root       666        2097152    2                       \n0x00038c0e 131075     root       777        2072       1                       \n0x00038c14 163844     root       777        5603392    0                       \n0x00038c09 196613     root       777        221248     0                       \n\n[root@tencent64 ~]# free -g\n             total       used       free     shared    buffers     cached\nMem:           126         30         95          0          0         16\n-\/+ buffers\/cache:         14        111\nSwap:            2          0          2\n<\/code><\/pre>\n
    \u5220\u9664\u5171\u4eab\u5185\u5b58\u540e\uff0ccache\u88ab\u6b63\u5e38\u91ca\u653e\u4e86\u3002\u8fd9\u4e2a\u884c\u4e3a\u4e0etmpfs\u7684\u903b\u8f91\u7c7b\u4f3c\u3002\u5185\u6838\u5e95\u5c42\u5728\u5b9e\u73b0\u5171\u4eab\u5185\u5b58\uff08shm\uff09\u3001\u6d88\u606f\u961f\u5217\uff08msg\uff09\u548c\u4fe1\u53f7\u91cf\u6570\u7ec4\uff08sem\uff09\u8fd9\u4e9bPOSIX:XSI\u7684IPC\u673a\u5236\u7684\u5185\u5b58\u5b58\u50a8\u65f6\uff0c\u4f7f\u7528\u7684\u90fd\u662ftmpfs\u3002\u8fd9\u4e5f\u662f\u4e3a\u4ec0\u4e48\u5171\u4eab\u5185\u5b58\u7684\u64cd\u4f5c\u903b\u8f91\u4e0etmpfs\u7c7b\u4f3c\u7684\u539f\u56e0\u3002\u5f53\u7136\uff0c\u4e00\u822c\u60c5\u51b5\u4e0b\u662fshm\u5360\u7528\u7684\u5185\u5b58\u66f4\u591a\uff0c\u6240\u4ee5\u6211\u4eec\u5728\u6b64\u91cd\u70b9\u5f3a\u8c03\u5171\u4eab\u5185\u5b58\u7684\u4f7f\u7528\u3002\u8bf4\u5230\u5171\u4eab\u5185\u5b58\uff0cLinux\u8fd8\u7ed9\u6211\u4eec\u63d0\u4f9b\u4e86\u53e6\u5916\u4e00\u79cd\u5171\u4eab\u5185\u5b58\u7684\u65b9\u6cd5\uff0c\u5c31\u662f\uff1a<\/p>\n
    mmap<\/h3>\n
    mmap()\u662f\u4e00\u4e2a\u975e\u5e38\u91cd\u8981\u7684\u7cfb\u7edf\u8c03\u7528\uff0c\u8fd9\u4ec5\u4ecemmap\u672c\u8eab\u7684\u529f\u80fd\u63cf\u8ff0\u4e0a\u662f\u770b\u4e0d\u51fa\u6765\u7684\u3002\u4ece\u5b57\u9762\u4e0a\u770b\uff0cmmap\u5c31\u662f\u5c06\u4e00\u4e2a\u6587\u4ef6\u6620\u5c04\u8fdb\u8fdb\u7a0b\u7684\u865a\u62df\u5185\u5b58\u5730\u5740\uff0c\u4e4b\u540e\u5c31\u53ef\u4ee5\u901a\u8fc7\u64cd\u4f5c\u5185\u5b58\u7684\u65b9\u5f0f\u5bf9\u6587\u4ef6\u7684\u5185\u5bb9\u8fdb\u884c\u64cd\u4f5c\u3002\u4f46\u662f\u5b9e\u9645\u4e0a\u8fd9\u4e2a\u8c03\u7528\u7684\u7528\u9014\u662f\u5f88\u5e7f\u6cdb\u7684\u3002\u5f53malloc\u7533\u8bf7\u5185\u5b58\u65f6\uff0c\u5c0f\u6bb5\u5185\u5b58\u5185\u6838\u4f7f\u7528sbrk\u5904\u7406\uff0c\u800c\u5927\u6bb5\u5185\u5b58\u5c31\u4f1a\u4f7f\u7528mmap\u3002\u5f53\u7cfb\u7edf\u8c03\u7528exec\u65cf\u51fd\u6570\u6267\u884c\u65f6\uff0c\u56e0\u4e3a\u5176\u672c\u8d28\u4e0a\u662f\u5c06\u4e00\u4e2a\u53ef\u6267\u884c\u6587\u4ef6\u52a0\u8f7d\u5230\u5185\u5b58\u6267\u884c\uff0c\u6240\u4ee5\u5185\u6838\u5f88\u81ea\u7136\u7684\u5c31\u53ef\u4ee5\u4f7f\u7528mmap\u65b9\u5f0f\u8fdb\u884c\u5904\u7406\u3002\u6211\u4eec\u5728\u6b64\u4ec5\u4ec5\u8003\u8651\u4e00\u79cd\u60c5\u51b5\uff0c\u5c31\u662f\u4f7f\u7528mmap\u8fdb\u884c\u5171\u4eab\u5185\u5b58\u7684\u7533\u8bf7\u65f6\uff0c\u4f1a\u4e0d\u4f1a\u8ddfshmget()\u4e00\u6837\u4e5f\u4f7f\u7528cache\uff1f<\/p>\n
    \u540c\u6837\uff0c\u6211\u4eec\u4e5f\u9700\u8981\u4e00\u4e2a\u7b80\u5355\u7684\u6d4b\u8bd5\u7a0b\u5e8f\uff1a<\/p>\n
    [root@tencent64 ~]# cat mmap.c \n#include <stdlib.h>\n#include <stdio.h>\n#include <strings.h>\n#include <sys\/mman.h>\n#include <sys\/stat.h>\n#include <sys\/types.h>\n#include <fcntl.h>\n#include <unistd.h>\n\n#define MEMSIZE 1024*1024*1023*2\n#define MPFILE \".\/mmapfile\"\n\nint main()\n{\n    void *ptr;\n    int fd;\n\n    fd = open(MPFILE, O_RDWR);\n    if (fd < 0) {\n        perror(\"open()\");\n        exit(1);\n    }\n\n    ptr = mmap(NULL, MEMSIZE, PROT_READ|PROT_WRITE, MAP_SHARED|MAP_ANON, fd, 0);\n    if (ptr == NULL) {\n        perror(\"malloc()\");\n        exit(1);\n    }\n\n    printf(\"%p\\n\", ptr);\n    bzero(ptr, MEMSIZE);\n\n    sleep(100);\n\n    munmap(ptr, MEMSIZE);\n    close(fd);\n\n    exit(1);\n}\n<\/code><\/pre>\n
    \u8fd9\u6b21\u6211\u4eec\u5e72\u8106\u4e0d\u7528\u4ec0\u4e48\u7236\u5b50\u8fdb\u7a0b\u7684\u65b9\u5f0f\u4e86\uff0c\u5c31\u4e00\u4e2a\u8fdb\u7a0b\uff0c\u7533\u8bf7\u4e00\u6bb52G\u7684mmap\u5171\u4eab\u5185\u5b58\uff0c\u7136\u540e\u521d\u59cb\u5316\u8fd9\u6bb5\u7a7a\u95f4\u4e4b\u540e\u7b49\u5f85100\u79d2\uff0c\u518d\u89e3\u9664\u5f71\u5c04\u6240\u4ee5\u6211\u4eec\u9700\u8981\u5728\u5b83sleep\u8fd9100\u79d2\u5185\u68c0\u67e5\u6211\u4eec\u7684\u7cfb\u7edf\u5185\u5b58\u4f7f\u7528\uff0c\u770b\u770b\u5b83\u7528\u7684\u662f\u4ec0\u4e48\u7a7a\u95f4\uff1f\u5f53\u7136\u5728\u8fd9\u4e4b\u524d\u8981\u5148\u521b\u5efa\u4e00\u4e2a2G\u7684\u6587\u4ef6.\/mmapfile\u3002\u7ed3\u679c\u5982\u4e0b\uff1a<\/p>\n
    [root@tencent64 ~]# dd if=\/dev\/zero of=mmapfile bs=1G count=2\n[root@tencent64 ~]# echo 3 > \/proc\/sys\/vm\/drop_caches\n[root@tencent64 ~]# free -g\n             total       used       free     shared    buffers     cached\nMem:           126         30         95          0          0         16\n-\/+ buffers\/cache:         14        111\nSwap:            2          0          2\n<\/code><\/pre>\n
    \u7136\u540e\u6267\u884c\u6d4b\u8bd5\u7a0b\u5e8f\uff1a<\/p>\n
    [root@tencent64 ~]# .\/mmap &\n[1] 19157\n0x7f1ae3635000\n[root@tencent64 ~]# free -g\n             total       used       free     shared    buffers     cached\nMem:           126         32         93          0          0         18\n-\/+ buffers\/cache:         14        111\nSwap:            2          0          2\n\n[root@tencent64 ~]# echo 3 > \/proc\/sys\/vm\/drop_caches\n[root@tencent64 ~]# free -g\n             total       used       free     shared    buffers     cached\nMem:           126         32         93          0          0         18\n-\/+ buffers\/cache:         14        111\nSwap:            2          0          2\n<\/code><\/pre>\n
    \u6211\u4eec\u53ef\u4ee5\u770b\u5230\uff0c\u5728\u7a0b\u5e8f\u6267\u884c\u671f\u95f4\uff0ccached\u4e00\u76f4\u4e3a18G\uff0c\u6bd4\u4e4b\u524d\u6da8\u4e862G\uff0c\u5e76\u4e14\u6b64\u65f6\u8fd9\u6bb5cache\u4ecd\u7136\u65e0\u6cd5\u88ab\u56de\u6536\u3002\u7136\u540e\u6211\u4eec\u7b49\u5f85100\u79d2\u4e4b\u540e\u7a0b\u5e8f\u7ed3\u675f\u3002<\/p>\n
    [root@tencent64 ~]# \n[1]+  Exit 1                  .\/mmap\n[root@tencent64 ~]# \n[root@tencent64 ~]# free -g\n             total       used       free     shared    buffers     cached\nMem:           126         30         95          0          0         16\n-\/+ buffers\/cache:         14        111\nSwap:            2          0          2\n<\/code><\/pre>\n
    \u7a0b\u5e8f\u9000\u51fa\u4e4b\u540e\uff0ccached\u5360\u7528\u7684\u7a7a\u95f4\u88ab\u91ca\u653e\u3002\u8fd9\u6837\u6211\u4eec\u53ef\u4ee5\u770b\u5230\uff0c\u4f7f\u7528mmap\u7533\u8bf7\u6807\u5fd7\u72b6\u6001\u4e3aMAP_SHARED\u7684\u5185\u5b58\uff0c\u5185\u6838\u4e5f\u662f\u4f7f\u7528\u7684cache\u8fdb\u884c\u5b58\u50a8\u7684\u3002\u5728\u8fdb\u7a0b\u5bf9\u76f8\u5173\u5185\u5b58\u6ca1\u6709\u91ca\u653e\u4e4b\u524d\uff0c\u8fd9\u6bb5cache\u4e5f\u662f\u4e0d\u80fd\u88ab\u6b63\u5e38\u91ca\u653e\u7684\u3002\u5b9e\u9645\u4e0a\uff0cmmap\u7684MAP_SHARED\u65b9\u5f0f\u7533\u8bf7\u7684\u5185\u5b58\uff0c\u5728\u5185\u6838\u4e2d\u4e5f\u662f\u7531tmpfs\u5b9e\u73b0\u7684\u3002\u7531\u6b64\u6211\u4eec\u4e5f\u53ef\u4ee5\u63a8\u6d4b\uff0c\u7531\u4e8e\u5171\u4eab\u5e93\u7684\u53ea\u8bfb\u90e8\u5206\u5728\u5185\u5b58\u4e2d\u90fd\u662f\u4ee5mmap\u7684MAP_SHARED\u65b9\u5f0f\u8fdb\u884c\u7ba1\u7406\uff0c\u5b9e\u9645\u4e0a\u5b83\u4eec\u4e5f\u90fd\u662f\u8981\u5360\u7528cache\u4e14\u65e0\u6cd5\u88ab\u91ca\u653e\u7684\u3002<\/p>\n
    \u6700\u540e<\/h2>\n
    \u6211\u4eec\u901a\u8fc7\u4e09\u4e2a\u6d4b\u8bd5\u4f8b\u5b50\uff0c\u53d1\u73b0Linux\u7cfb\u7edf\u5185\u5b58\u4e2d\u7684cache\u5e76\u4e0d\u662f\u5728\u6240\u6709\u60c5\u51b5\u4e0b\u90fd\u80fd\u88ab\u91ca\u653e\u5f53\u505a\u7a7a\u95f2\u7a7a\u95f4\u7528\u7684\u3002\u5e76\u4e14\u4e5f\u4e5f\u660e\u786e\u4e86\uff0c\u5373\u4f7f\u53ef\u4ee5\u91ca\u653ecache\uff0c\u4e5f\u5e76\u4e0d\u662f\u5bf9\u7cfb\u7edf\u6765\u8bf4\u6ca1\u6709\u6210\u672c\u7684\u3002\u603b\u7ed3\u4e00\u4e0b\u8981\u70b9\uff0c\u6211\u4eec\u5e94\u8be5\u8bb0\u5f97\u8fd9\u6837\u51e0\u70b9\uff1a<\/p>\n
      \n
    1. \u5f53cache\u4f5c\u4e3a\u6587\u4ef6\u7f13\u5b58\u88ab\u91ca\u653e\u7684\u65f6\u5019\u4f1a\u5f15\u53d1IO\u53d8\u9ad8\uff0c\u8fd9\u662fcache\u52a0\u5feb\u6587\u4ef6\u8bbf\u95ee\u901f\u5ea6\u6240\u8981\u4ed8\u51fa\u7684\u6210\u672c\u3002<\/li>\n
    2. tmpfs\u4e2d\u5b58\u50a8\u7684\u6587\u4ef6\u4f1a\u5360\u7528cache\u7a7a\u95f4\uff0c\u9664\u975e\u6587\u4ef6\u5220\u9664\u5426\u5219\u8fd9\u4e2acache\u4e0d\u4f1a\u88ab\u81ea\u52a8\u91ca\u653e\u3002<\/li>\n
    3. \u4f7f\u7528shmget\u65b9\u5f0f\u7533\u8bf7\u7684\u5171\u4eab\u5185\u5b58\u4f1a\u5360\u7528cache\u7a7a\u95f4\uff0c\u9664\u975e\u5171\u4eab\u5185\u5b58\u88abipcrm\u6216\u8005\u4f7f\u7528shmctl\u53bbIPC_RMID\uff0c\u5426\u5219\u76f8\u5173\u7684cache\u7a7a\u95f4\u90fd\u4e0d\u4f1a\u88ab\u81ea\u52a8\u91ca\u653e\u3002<\/li>\n
    4. \u4f7f\u7528mmap\u65b9\u6cd5\u7533\u8bf7\u7684MAP_SHARED\u6807\u5fd7\u7684\u5185\u5b58\u4f1a\u5360\u7528cache\u7a7a\u95f4\uff0c\u9664\u975e\u8fdb\u7a0b\u5c06\u8fd9\u6bb5\u5185\u5b58munmap\uff0c\u5426\u5219\u76f8\u5173\u7684cache\u7a7a\u95f4\u90fd\u4e0d\u4f1a\u88ab\u81ea\u52a8\u91ca\u653e\u3002<\/li>\n
    5. \u5b9e\u9645\u4e0ashmget\u3001mmap\u7684\u5171\u4eab\u5185\u5b58\uff0c\u5728\u5185\u6838\u5c42\u90fd\u662f\u901a\u8fc7tmpfs\u5b9e\u73b0\u7684\uff0ctmpfs\u5b9e\u73b0\u7684\u5b58\u50a8\u7528\u7684\u90fd\u662fcache\u3002<\/li>\n<\/ol>\n
      \u5f53\u7406\u89e3\u4e86\u8fd9\u4e9b\u7684\u65f6\u5019\uff0c\u5e0c\u671b\u5927\u5bb6\u5bf9free\u547d\u4ee4\u7684\u7406\u89e3\u53ef\u4ee5\u8fbe\u5230\u6211\u4eec\u8bf4\u7684\u7b2c\u4e09\u4e2a\u5c42\u6b21\u3002\u6211\u4eec\u5e94\u8be5\u660e\u767d\uff0c\u5185\u5b58\u7684\u4f7f\u7528\u5e76\u4e0d\u662f\u7b80\u5355\u7684\u6982\u5ff5\uff0ccache\u4e5f\u5e76\u4e0d\u662f\u771f\u7684\u53ef\u4ee5\u5f53\u6210\u7a7a\u95f2\u7a7a\u95f4\u7528\u7684\u3002\u5982\u679c\u6211\u4eec\u8981\u771f\u6b63\u6df1\u523b\u7406\u89e3\u4f60\u7684\u7cfb\u7edf\u4e0a\u7684\u5185\u5b58\u5230\u5e95\u4f7f\u7528\u7684\u662f\u5426\u5408\u7406\uff0c\u662f\u9700\u8981\u7406\u89e3\u6e05\u695a\u5f88\u591a\u66f4\u7ec6\u8282\u77e5\u8bc6\uff0c\u5e76\u4e14\u5bf9\u76f8\u5173\u4e1a\u52a1\u7684\u5b9e\u73b0\u505a\u66f4\u7ec6\u8282\u5224\u65ad\u7684\u3002\u6211\u4eec\u5f53\u524d\u5b9e\u9a8c\u573a\u666f\u662fCentos 6\u7684\u73af\u5883\uff0c\u4e0d\u540c\u7248\u672c\u7684Linux\u7684free\u73b0\u5b9e\u7684\u72b6\u6001\u53ef\u80fd\u4e0d\u4e00\u6837\uff0c\u5927\u5bb6\u53ef\u4ee5\u81ea\u5df1\u53bb\u627e\u51fa\u4e0d\u540c\u7684\u539f\u56e0\u3002<\/p>\n
      \u5f53\u7136\uff0c\u672c\u6587\u6240\u8ff0\u7684\u4e5f\u4e0d\u662f\u6240\u6709\u7684cache\u4e0d\u80fd\u88ab\u91ca\u653e\u7684\u60c5\u5f62\u3002\u90a3\u4e48\uff0c\u5728\u4f60\u7684\u5e94\u7528\u573a\u666f\u4e0b\uff0c\u8fd8\u6709\u90a3\u4e9bcache\u4e0d\u80fd\u88ab\u91ca\u653e\u7684\u573a\u666f\u5462\uff1f<\/p>\n
      \u6458\u81ea\uff1ahttp:\/\/liwei.life\/2016\/04\/26\/linux%E5%86%85%E5%AD%98%E4%B8%AD%E7%9A%84cache%E7%9C%9F%E7%9A%84%E8%83%BD%E8%A2%AB%E5%9B%9E%E6%94%B6%E4%B9%88%EF%BC%9F\/#rd<\/p>\n","protected":false},"excerpt":{"rendered":"
      \u5927\u5bb6\u666e\u904d\u8ba4\u4e3a\uff0cbuffers\u548ccached\u6240\u5360\u7528\u7684\u5185\u5b58\u7a7a\u95f4\u662f\u53ef\u4ee5\u5728\u5185\u5b58\u538b\u529b\u8f83\u5927\u7684\u65f6\u5019\u88ab\u91ca\u653e\u5f53\u505a\u7a7a\u95f2\u7a7a\u95f4\u7528\u7684\u3002\u4f46\u771f\u7684\u662f\u8fd9\u6837\u4e48\uff1f\u5728\u8bba\u8bc1\u8fd9\u4e2a\u9898\u76ee\u4e4b\u524d\uff0c\u6211\u4eec\u5148\u7b80\u8981\u4ecb\u7ecd\u4e00\u4e0bbuffers\u548ccached\u662f\u4ec0\u4e48\u610f\u601d<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[31],"tags":[379,378,380],"_links":{"self":[{"href":"https:\/\/yanjingang.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/800"}],"collection":[{"href":"https:\/\/yanjingang.com\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/yanjingang.com\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/yanjingang.com\/blog\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/yanjingang.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=800"}],"version-history":[{"count":0,"href":"https:\/\/yanjingang.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/800\/revisions"}],"wp:attachment":[{"href":"https:\/\/yanjingang.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=800"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/yanjingang.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=800"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/yanjingang.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=800"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}