{"id":248,"date":"2021-07-28T13:29:01","date_gmt":"2021-07-28T05:29:01","guid":{"rendered":"http:\/\/egonlin.com\/?p=248"},"modified":"2022-04-06T19:07:14","modified_gmt":"2022-04-06T11:07:14","slug":"%e7%ac%ac%e4%b8%89%e8%8a%82%ef%bc%9a%e9%87%8a%e6%94%be%e7%bc%93%e5%ad%98","status":"publish","type":"post","link":"https:\/\/egonlin.com\/?p=248","title":{"rendered":"\u7b2c\u4e09\u8282\uff1a\u91ca\u653e\u7f13\u5b58"},"content":{"rendered":"<pre><code class=\"language-python\">\u5f53\u5728Linux\u4e0b\u9891\u7e41\u5b58\u53d6\u6587\u4ef6\u540e\uff0c\u7269\u7406\u5185\u5b58\u4f1a\u5f88\u5feb\u88ab\u7528\u5149\uff0c\u5f53\u7a0b\u5e8f\u7ed3\u675f\u540e\uff0c\u5185\u5b58\u4e0d\u4f1a\u88ab\u6b63\u5e38\u91ca\u653e\uff0c\u800c\u662f\u4e00\u76f4\u4f5c\u4e3acaching\u3002\u8fd9\u4e2a\u95ee\u9898\uff0c\u8c8c\u4f3c\u6709\u4e0d\u5c11\u4eba\u5728\u95ee\uff0c\u4e0d\u8fc7\u90fd\u6ca1\u6709\u770b\u5230\u6709\u4ec0\u4e48\u5f88\u597d\u89e3\u51b3\u7684\u529e\u6cd5\u3002\u90a3\u4e48\u6211\u6765\u8c08\u8c08\u8fd9\u4e2a\u95ee\u9898\u3002\n\n\/proc\u662f\u4e00\u4e2a\u865a\u62df\u6587\u4ef6\u7cfb\u7edf\uff0c\u6211\u4eec\u53ef\u4ee5\u901a\u8fc7\u5bf9\u5b83\u7684\u8bfb\u5199\u64cd\u4f5c\u505a\u4e3a\u4e0ekernel\u5b9e\u4f53\u95f4\u8fdb\u884c\u901a\u4fe1\u7684\u4e00\u79cd\u624b\u6bb5\u3002\u4e5f\u5c31\u662f\u8bf4\u53ef\u4ee5\u901a\u8fc7\u4fee\u6539\/proc\u4e2d\u7684\u6587\u4ef6\uff0c\u6765\u5bf9\u5f53\u524dkernel\u7684\u884c\u4e3a\u505a\u51fa\u8c03\u6574\u3002\u90a3\u4e48\u6211\u4eec\u53ef\u4ee5\u901a\u8fc7\u8c03\u6574\/proc\/sys\/vm\/drop_caches\u6765\u91ca\u653e\u5185\u5b58\u3002\u64cd\u4f5c\u5982\u4e0b\uff1a\n\u9996\u5148\uff0c\u67e5\u770b\/proc\/sys\/vm\/drop_caches\u7684\u503c\n[root@server test]# cat \/proc\/sys\/vm\/drop_caches\n0\n\n\u503c\u9ed8\u8ba4\u4e3a0\n\u7136\u540e\uff0c\u8fd0\u884csync\u547d\u4ee4\n[root@server test]# sync\n\u624b\u52a8\u6267\u884csync\u547d\u4ee4\uff08\u63cf\u8ff0\uff1async \u547d\u4ee4\u8fd0\u884c sync \u5b50\u4f8b\u7a0b\u3002\u5982\u679c\u5fc5\u987b\u505c\u6b62\u7cfb\u7edf\uff0c\u5219\u8fd0\u884csync \u547d\u4ee4\u4ee5\u786e\u4fdd\u6587\u4ef6\u7cfb\u7edf\u7684\u5b8c\u6574\u6027\u3002sync \u547d\u4ee4\u5c06\u6240\u6709\u672a\u5199\u7684\u7cfb\u7edf\u7f13\u51b2\u533a\u5199\u5230\u78c1\u76d8\u4e2d\uff0c\u5305\u542b\u5df2\u4fee\u6539\u7684 i-node\u3001\u5df2\u5ef6\u8fdf\u7684\u5757 I\/O \u548c\u8bfb\u5199\u6620\u5c04\u6587\u4ef6\uff09\n\u6700\u540e\uff0c\u8f93\u5165\u624b\u52a8\u91ca\u653e\u5185\u5b58\u7684\u547d\u4ee4\n[root@server test]# echo 1 &gt; \/proc\/sys\/vm\/drop_caches\ndrop_caches\u7684\u503c\u53ef\u4ee5\u662f0-3\u4e4b\u95f4\u7684\u6570\u5b57\uff0c\u4ee3\u8868\u4e0d\u540c\u7684\u542b\u4e49\uff1a\n\n0\uff1a\u4e0d\u91ca\u653e\uff08\u7cfb\u7edf\u9ed8\u8ba4\u503c\uff09\n\n1\uff1a\u91ca\u653e\u9875\u7f13\u5b58\n\n2\uff1a\u91ca\u653edentries\u548cinodes\n\n3\uff1a\u91ca\u653e\u6240\u6709\u7f13\u5b58\n\n\u91ca\u653e\u5b8c\u5185\u5b58\u540e\u6539\u56de\u53bb\u8ba9\u7cfb\u7edf\u91cd\u65b0\u81ea\u52a8\u5206\u914d\u5185\u5b58\necho 0 &gt;\/proc\/sys\/vm\/drop_caches\nfree -m #\u770b\u5185\u5b58\u662f\u5426\u5df2\u7ecf\u91ca\u653e\u6389\u4e86\u3002\n\u5982\u679c\u6211\u4eec\u9700\u8981\u91ca\u653e\u6240\u6709\u7f13\u5b58\uff0c\u5c31\u8f93\u5165\u4e0b\u9762\u7684\u547d\u4ee4\uff1a\n[root@server test]# echo 3 &gt; \/proc\/sys\/vm\/drop_caches\n\n######### Linux\u91ca\u653e\u5185\u5b58\u7684\u76f8\u5173\u77e5\u8bc6 ###############\n\u5728Linux\u7cfb\u7edf\u4e0b\uff0c\u6211\u4eec\u4e00\u822c\u4e0d\u9700\u8981\u53bb\u91ca\u653e\u5185\u5b58\uff0c\u56e0\u4e3a\u7cfb\u7edf\u5df2\u7ecf\u5c06\u5185\u5b58\u7ba1\u7406\u7684\u5f88\u597d\u3002\u4f46\u662f\u51e1\u4e8b\u4e5f\u6709\u4f8b\u5916\uff0c\u6709\u7684\u65f6\u5019\u5185\u5b58\u4f1a\u88ab\u7f13\u5b58\u5360\u7528\u6389\uff0c\u5bfc\u81f4\u7cfb\u7edf\u4f7f\u7528SWAP\u7a7a\u95f4\u5f71\u54cd\u6027\u80fd\uff0c\u4f8b\u5982\u5f53\u4f60\u5728linux\u4e0b\u9891\u7e41\u5b58\u53d6\u6587\u4ef6\u540e,\u7269\u7406\u5185\u5b58\u4f1a\u5f88\u5feb\u88ab\u7528\u5149,\u5f53\u7a0b\u5e8f\u7ed3\u675f\u540e,\u5185\u5b58\u4e0d\u4f1a\u88ab\u6b63\u5e38\u91ca\u653e,\u800c\u662f\u4e00\u76f4\u4f5c\u4e3acaching\u3002\uff0c\u6b64\u65f6\u5c31\u9700\u8981\u6267\u884c\u91ca\u653e\u5185\u5b58\uff08\u6e05\u7406\u7f13\u5b58\uff09\u7684\u64cd\u4f5c\u4e86\u3002\n\nLinux\u7cfb\u7edf\u7684\u7f13\u5b58\u673a\u5236\u662f\u76f8\u5f53\u5148\u8fdb\u7684\uff0c\u4ed6\u4f1a\u9488\u5bf9dentry\uff08\u7528\u4e8eVFS\uff0c\u52a0\u901f\u6587\u4ef6\u8def\u5f84\u540d\u5230inode\u7684\u8f6c\u6362\uff09\u3001Buffer Cache\uff08\u9488\u5bf9\u78c1\u76d8\u5757\u7684\u8bfb\u5199\uff09\u548cPage Cache\uff08\u9488\u5bf9\u6587\u4ef6inode\u7684\u8bfb\u5199\uff09\u8fdb\u884c\u7f13\u5b58\u64cd\u4f5c\u3002\u4f46\u662f\u5728\u8fdb\u884c\u4e86\u5927\u91cf\u6587\u4ef6\u64cd\u4f5c\u4e4b\u540e\uff0c\u7f13\u5b58\u4f1a\u628a\u5185\u5b58\u8d44\u6e90\u57fa\u672c\u7528\u5149\u3002\u4f46\u5b9e\u9645\u4e0a\u6211\u4eec\u6587\u4ef6\u64cd\u4f5c\u5df2\u7ecf\u5b8c\u6210\uff0c\u8fd9\u90e8\u5206\u7f13\u5b58\u5df2\u7ecf\u7528\u4e0d\u5230\u4e86\u3002\u8fd9\u4e2a\u65f6\u5019\uff0c\u6211\u4eec\u96be\u9053\u53ea\u80fd\u773c\u7741\u7741\u7684\u770b\u7740\u7f13\u5b58\u628a\u5185\u5b58\u7a7a\u95f4\u5360\u636e\u6389\u5417\uff1f\u6240\u4ee5\uff0c\u6211\u4eec\u8fd8\u662f\u6709\u5fc5\u8981\u6765\u624b\u52a8\u8fdb\u884cLinux\u4e0b\u91ca\u653e\u5185\u5b58\u7684\u64cd\u4f5c\uff0c\u5176\u5b9e\u4e5f\u5c31\u662f\u91ca\u653e\u7f13\u5b58\u7684\u64cd\u4f5c\u4e86\u3002\/proc\u662f\u4e00\u4e2a\u865a\u62df\u6587\u4ef6\u7cfb\u7edf,\u6211\u4eec\u53ef\u4ee5\u901a\u8fc7\u5bf9\u5b83\u7684\u8bfb\u5199\u64cd\u4f5c\u505a\u4e3a\u4e0ekernel\u5b9e\u4f53\u95f4\u8fdb\u884c\u901a\u4fe1\u7684\u4e00\u79cd\u624b\u6bb5.\u4e5f\u5c31\u662f\u8bf4\u53ef\u4ee5\u901a\u8fc7\u4fee\u6539\/proc\u4e2d\u7684\u6587\u4ef6,\u6765\u5bf9\u5f53\u524dkernel\u7684\u884c\u4e3a\u505a\u51fa\u8c03\u6574.\u90a3\u4e48\u6211\u4eec\u53ef\u4ee5\u901a\u8fc7\u8c03\u6574\/proc\/sys\/vm\/drop_caches\u6765\u91ca\u653e\u5185\u5b58\u3002\u8981\u8fbe\u5230\u91ca\u653e\u7f13\u5b58\u7684\u76ee\u7684\uff0c\u6211\u4eec\u9996\u5148\u9700\u8981\u4e86\u89e3\u4e0b\u5173\u952e\u7684\u914d\u7f6e\u6587\u4ef6\/proc\/sys\/vm\/drop_caches\u3002\u8fd9\u4e2a\u6587\u4ef6\u4e2d\u8bb0\u5f55\u4e86\u7f13\u5b58\u91ca\u653e\u7684\u53c2\u6570\uff0c\u9ed8\u8ba4\u503c\u4e3a0\uff0c\u4e5f\u5c31\u662f\u4e0d\u91ca\u653e\u7f13\u5b58\u3002\n\n\u4e00\u822c\u590d\u5236\u4e86\u6587\u4ef6\u540e,\u53ef\u7528\u5185\u5b58\u4f1a\u53d8\u5c11\uff0c\u90fd\u88abcached\u5360\u7528\u4e86\uff0c\u8fd9\u662flinux\u4e3a\u4e86\u63d0\u9ad8\u6587\u4ef6\u8bfb\u53d6\u6548\u7387\u7684\u505a\u6cd5\uff1a\u4e3a\u4e86\u63d0\u9ad8\u78c1\u76d8\u5b58\u53d6\u6548\u7387, Linux\u505a\u4e86\u4e00\u4e9b\u7cbe\u5fc3\u7684\u8bbe\u8ba1, \u9664\u4e86\u5bf9dentry\u8fdb\u884c\u7f13\u5b58(\u7528\u4e8eVFS,\u52a0\u901f\u6587\u4ef6\u8def\u5f84\u540d\u5230inode\u7684\u8f6c\u6362), \u8fd8\u91c7\u53d6\u4e86\u4e24\u79cd\u4e3b\u8981Cache\u65b9\u5f0f\uff1aBuffer Cache\u548cPage Cache\u3002\u524d\u8005\u9488\u5bf9\u78c1\u76d8\u5757\u7684\u8bfb\u5199\uff0c\u540e\u8005\u9488\u5bf9\u6587\u4ef6inode\u7684\u8bfb\u5199\u3002\u8fd9\u4e9bCache\u6709\u6548\u7f29\u77ed\u4e86 I\/O\u7cfb\u7edf\u8c03\u7528(\u6bd4\u5982read,write,getdents)\u7684\u65f6\u95f4\u3002&quot;\n\n\u91ca\u653e\u5185\u5b58\u524d\u5148\u4f7f\u7528sync\u547d\u4ee4\u505a\u540c\u6b65\uff0c\u4ee5\u786e\u4fdd\u6587\u4ef6\u7cfb\u7edf\u7684\u5b8c\u6574\u6027\uff0c\u5c06\u6240\u6709\u672a\u5199\u7684\u7cfb\u7edf\u7f13\u51b2\u533a\u5199\u5230\u78c1\u76d8\u4e2d\uff0c\u5305\u542b\u5df2\u4fee\u6539\u7684 i-node\u3001\u5df2\u5ef6\u8fdf\u7684\u5757 I\/O \u548c\u8bfb\u5199\u6620\u5c04\u6587\u4ef6\u3002\u5426\u5219\u5728\u91ca\u653e\u7f13\u5b58\u7684\u8fc7\u7a0b\u4e2d\uff0c\u53ef\u80fd\u4f1a\u4e22\u5931\u672a\u4fdd\u5b58\u7684\u6587\u4ef6\u3002\n\n[root@localhost ~]# free -m\ntotal used free shared buffers cached\nMem: 7979 7897 82 0 30 3918\n-\/ buffers\/cache: 3948 4031\nSwap: 4996 438 4558\n\n\u7b2c\u4e00\u884c\u7528\u5168\u5c40\u89d2\u5ea6\u63cf\u8ff0\u7cfb\u7edf\u4f7f\u7528\u7684\u5185\u5b58\u72b6\u51b5\uff1a\n\ntotal \u5185\u5b58\u603b\u6570\n\nused \u5df2\u7ecf\u4f7f\u7528\u7684\u5185\u5b58\u6570\uff0c\u4e00\u822c\u60c5\u51b5\u8fd9\u4e2a\u503c\u4f1a\u6bd4\u8f83\u5927\uff0c\u56e0\u4e3a\u8fd9\u4e2a\u503c\u5305\u62ec\u4e86cache \u5e94\u7528\u7a0b\u5e8f\u4f7f\u7528\u7684\u5185\u5b58\n\nfree \u7a7a\u95f2\u7684\u5185\u5b58\u6570\n\nshared \u591a\u4e2a\u8fdb\u7a0b\u5171\u4eab\u7684\u5185\u5b58\u603b\u989d\n\nbuffers \u7f13\u5b58\uff0c\u4e3b\u8981\u7528\u4e8e\u76ee\u5f55\u65b9\u9762,inode\u503c\u7b49\uff08ls\u5927\u76ee\u5f55\u53ef\u770b\u5230\u8fd9\u4e2a\u503c\u589e\u52a0\uff09\n\ncached \u7f13\u5b58\uff0c\u7528\u4e8e\u5df2\u6253\u5f00\u7684\u6587\u4ef6\n\n\u7b2c\u4e8c\u884c\u63cf\u8ff0\u5e94\u7528\u7a0b\u5e8f\u7684\u5185\u5b58\u4f7f\u7528\uff1a\n\n-buffers\/cache \u7684\u5185\u5b58\u6570:used - buffers - cached\n\nbuffers\/cache \u7684\u5185\u5b58\u6570:free buffers cached\n\n\u524d\u4e2a\u503c\u8868\u793a-buffers\/cache \u5e94\u7528\u7a0b\u5e8f\u4f7f\u7528\u7684\u5185\u5b58\u5927\u5c0f\uff0cused\u51cf\u53bb\u7f13\u5b58\u503c\n\n\u540e\u4e2a\u503c\u8868\u793a buffers\/cache \u6240\u6709\u53ef\u4f9b\u5e94\u7528\u7a0b\u5e8f\u4f7f\u7528\u7684\u5185\u5b58\u5927\u5c0f\uff0cfree\u52a0\u4e0a\u7f13\u5b58\u503c\n\n\u7b2c\u4e09\u884c\u8868\u793aswap\u7684\u4f7f\u7528\uff1a\n\nused \u5df2\u4f7f\u7528\n\nfree \u672a\u4f7f\u7528\n\n\u53ef\u7528\u7684\u5185\u5b58=free memory buffers cached\u3002\n\u4e3a\u4ec0\u4e48free\u8fd9\u4e48\u5c0f\uff0c\u662f\u5426\u5173\u95ed\u5e94\u7528\u540e\u5185\u5b58\u6ca1\u6709\u91ca\u653e\uff1f\n\n\u4f46\u5b9e\u9645\u4e0a\uff0c\u6211\u4eec\u90fd\u77e5\u9053\u8fd9\u662f\u56e0\u4e3aLinux\u5bf9\u5185\u5b58\u7684\u7ba1\u7406\u4e0eWindows\u4e0d\u540c\uff0cfree\u5c0f\u5e76\u4e0d\u662f\u8bf4\u5185\u5b58\u4e0d\u591f\u7528\u4e86\uff0c\u5e94\u8be5\u770b\u7684\u662ffree\u7684\u7b2c\u4e8c\u884c\u6700\u540e\u4e00\u4e2a\u503c\uff1a-\/ buffers\/cache: 3948 4031 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