{"id":7424,"date":"2022-08-30T11:49:25","date_gmt":"2022-08-30T03:49:25","guid":{"rendered":"https:\/\/egonlin.com\/?p=7424"},"modified":"2022-10-22T17:01:33","modified_gmt":"2022-10-22T09:01:33","slug":"04-%e8%84%8f%e6%95%b0%e6%8d%ae%e5%af%b9%e5%ae%b9%e5%99%a8%e8%af%bb%e5%86%99%e6%80%a7%e8%83%bd%e7%9a%84%e5%bd%b1%e5%93%8d","status":"publish","type":"post","link":"https:\/\/egonlin.com\/?p=7424","title":{"rendered":"01 \u810f\u6570\u636e\u5bf9\u5bb9\u5668\u8bfb\u5199\u6027\u80fd\u7684\u5f71\u54cd"},"content":{"rendered":"<h1>\u4e00 \u5f15\u5165\u95ee\u9898<\/h1>\n<p>1\u3001\u601d\u8003\u4e00\u4e2a\u95ee\u9898<\/p>\n<p>\u6709\u4e00\u4e2a\u5bb9\u5668\uff0c\u91cc\u9762\u8fd0\u884c\u7684\u8fdb\u7a0b\u9700\u8981\u5199\u4e00\u4e2a10G\u7684\u6587\u4ef6\uff0c\u5177\u4f53\u662f\u5982\u4f55\u5199\u7684\u5462?<br \/>\n\u4ece\u6e90\u6587\u4ef6\u4e2d\u6bcf\u6b21\u53ea\u8bfb\u53d6\u4e00\u4e2a100KB\u5927\u5c0f\u7684\u6570\u5757\uff0c\u7136\u540e\u5199\u5165\u4e00\u4e2a\u65b0\u6587\u4ef6\uff0c\u4e0d\u65ad\u5730\u5199\uff0c\u76f4\u5230\u5199\u5b8c10G\u5927\u5c0f\u7684\u6570\u636e\u3002<\/p>\n<p>2\u3001\u95ee\uff1a\u4f60\u5982\u679c\u4e3a\u8be5\u5bb9\u5668\u5206\u914d\u8d44\u6e90\uff1f<\/p>\n<p>\u5f88\u591a\u4eba\u90fd\u4f1a\u89c9\u5f97\uff0c\u53ea\u9700\u8981\u4fdd\u8bc1\u78c1\u76d8\u7a7a\u95f4\u591f\u7528\u5c31\u53ef\u4ee5\u4e86\uff0c\u4e0d\u9700\u8981\u8003\u8651\u5185\u5b58\uff0c\u8fd9\u5176\u5b9e\u662f\u6709\u95ee\u9898\u7684\uff0c\u6b64\u65f6\u5982\u679c\u5185\u5b58\u5f88\u5c0f\u6bd4\u5982\u53ea\u67091G\uff0c\u4f60\u4f1a\u53d1\u73b0\u5bb9\u5668\u7684\u6574\u4f53\u8bfb\u5199\u6548\u7387\u6709\u6ce2\u52a8\uff0c\u6709\u65f6\u5019\u901f\u5ea6\u8fd8\u53ef\u4ee5\uff0c\u6709\u65f6\u5019\u5c31\u5f88\u6162<\/p>\n<p>3\u3001\u4e3a\u4ec0\u4e48\uff1f\uff1f\uff1f<\/p>\n<h1>\u4e8c \u50a8\u5907\u77e5\u8bc6<\/h1>\n<h2>2.1 VFS\u4ecb\u7ecd<\/h2>\n<p>FS\u5728\u6574\u4e2aLinux\u7cfb\u7edf\u4e2d\u7684\u67b6\u6784\u89c6\u56fe\u5982\u4e0b\uff0c\u4e86\u89e3\u4e86\u8fd9\u4e2a\u67b6\u6784\u4e4b\u540e\u6211\u4eec\u5c31\u80fd\u77e5\u9053\u7528\u6237\u5199\u5165\u6587\u4ef6\u7684\u6838\u5fc3\u6d41\u7a0b<br \/>\n<div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/egonlin.com\/wp-content\/uploads\/2022\/08\/image-1666414202238.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/egonlin.com\/wp-content\/uploads\/2022\/08\/image-1666414202238.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"file\" \/><\/div><\/p>\n<p>1\u3001\u5148\u6765\u4e86\u89e3\u4e00\u4e0bVFS\u865a\u62df\u6587\u4ef6\u7cfb\u7edf<\/p>\n<ul>\n<li>\n<p>VFS \u662f\u4ec0\u4e48<br \/>\nVFS\uff08Virtual Filesystem Switch\uff09\u79f0\u4e3a\u865a\u62df\u6587\u4ef6\u7cfb\u7edf\u6216\u865a\u62df\u6587\u4ef6\u7cfb\u7edf\u8f6c\u6362\uff0c\u662f\u4e00\u4e2a\u5185\u6838\u8f6f\u4ef6\u5c42\uff0c\u662f\u5728\u5177\u4f53\u7684\u6587\u4ef6\u7cfb\u7edffilesystem\u4e4b\u4e0a\u62bd\u8c61\u7684\u4e00\u5c42\uff0c\u7528\u6765\u5904\u7406\u4e0ePosix\u6587\u4ef6\u7cfb\u7edf\u76f8\u5173\u7684\u6240\u6709\u8c03\u7528\uff0c\u8868\u73b0\u4e3a\u80fd\u591f\u7ed9\u5404\u79cd\u6587\u4ef6\u7cfb\u7edf\u63d0\u4f9b\u4e00\u4e2a\u901a\u7528\u7684\u63a5\u53e3\uff0c\u4f7f\u4e0a\u5c42\u7684\u5e94\u7528\u7a0b\u5e8f\u80fd\u591f\u4f7f\u7528<strong>\u901a\u7528\u7684\u63a5\u53e3<\/strong>\u8bbf\u95ee\u4e0d\u540c\u6587\u4ef6\u7cfb\u7edffilesystem\uff0c\u540c\u65f6\u4e5f\u4e3a\u4e0d\u540c\u6587\u4ef6\u7cfb\u7edf\u7684\u901a\u4fe1\u63d0\u4f9b\u4e86\u5a92\u4ecb\u3002<\/p>\n<\/li>\n<li>\n<p>VFS \u7684\u4f5c\u7528<br \/>\n\u6982\u62ec\u5730\u8bb2\uff0cVFS \u6709\u4e24\u4e2a\u4f5c\u7528\uff1a<\/p>\n<p>\u5904\u7406\u4e0e Unix \u6807\u51c6\u6587\u4ef6\u7cfb\u7edf\u76f8\u5173\u7684\u6240\u6709\u7cfb\u7edf\u8c03\u7528<\/p>\n<p>\u4e3a\u5404\u79cd\u6587\u4ef6\u7cfb\u7edf\u63d0\u4f9b\u4e00\u4e2a\u901a\u7528\u7684\u63a5\u53e3<\/p>\n<\/li>\n<li>\n<p>VFS \u7684\u8bbe\u8ba1\u601d\u60f3<br \/>\nVFS \u8bbe\u8ba1\u7684\u521d\u8877\u5c31\u662f\u8981\u652f\u6301\u6240\u6709\u7684\u6587\u4ef6\u7cfb\u7edf\uff0c\u6240\u4ee5\u5b83\u7684\u8bbe\u8ba1\u601d\u60f3\u5176\u5b9e\u5c31\u662f\u4ee5\u9762\u5411\u5bf9\u8c61\u7684\u65b9\u5f0f\uff0c\u8bbe\u8ba1\u4e00\u4e2a\u901a\u7528\u7684\u6587\u4ef6\u6a21\u578b\uff0c\u51fa\u4e8e\u6548\u7387\u8003\u8651\uff0cVFS \u8fd8\u662f C \u8bed\u8a00\u5199\u7684\u3002<br \/>\n\u5728\u901a\u7528\u6587\u4ef6\u7cfb\u7edf\u6a21\u578b\u4e2d\uff0c\u6bcf\u4e2a\u76ee\u5f55\u4e5f\u88ab\u5f53\u4f5c\u4e00\u4e2a\u6587\u4ef6\uff0c\u53ef\u4ee5\u5305\u542b\u82e5\u5e72\u6587\u4ef6\u548c\u5176\u4ed6\u7684\u5b50\u76ee\u5f55\u3002\u56e0\u6b64\uff0cLinux \u6709\u4e00\u53e5\u7ecf\u5178\u7684\u8bdd\uff1a\u4e00\u5207\u7686\u6587\u4ef6\u3002<\/p>\n<\/li>\n<\/ul>\n<p>2\u3001\u7136\u540e\u518d\u6765\u770b\u4e00\u4e0b\u7528\u6237\u5199\u5165\u6587\u4ef6\u7684\u5927\u6982\u6d41\u7a0b<br \/>\n\u7528\u6237\u5199\u5165\u4e00\u4e2a\u6587\u4ef6\uff0c\u4f7f\u7528POSIX\u6807\u51c6\u7684write\u63a5\u53e3\uff0c\u4f1a\u88ab\u64cd\u4f5c\u7cfb\u7edf\u63a5\u7ba1\uff0c\u8f6c\u8c03sys_write\u8fd9\u4e2a\u7cfb\u7edf\u8c03\u7528\uff08\u5c5e\u4e8eSCI\u5c42\uff09\u3002\u7136\u540eVFS\u5c42\u63a5\u53d7\u5230\u8fd9\u4e2a\u8c03\u7528\uff0c\u901a\u8fc7\u81ea\u8eab\u62bd\u8c61\u7684\u6a21\u578b\uff0c\u8f6c\u6362\u4e3a\u5bf9\u7ed9\u5b9a\u6587\u4ef6\u7cfb\u7edffilesystem\u3001\u7ed9\u5b9a\u8bbe\u5907\u7684\u64cd\u4f5c\uff0c\u8fd9\u4e00\u5173\u952e\u6027\u7684\u6b65\u9aa4\u662fVFS\u7684\u6838\u5fc3\uff0c\u9700\u8981\u6709\u7edf\u4e00\u7684\u6a21\u578b\uff0c\u4f7f\u5f97\u5bf9\u4efb\u610f\u652f\u6301\u7684\u6587\u4ef6\u7cfb\u7edf\u90fd\u80fd\u5b9e\u73b0\u7cfb\u7edf\u7684\u529f\u80fd\u3002\u8fd9\u5c31\u662fVFS\u63d0\u4f9b\u7684\u7edf\u4e00\u7684\u6587\u4ef6\u6a21\u578b\uff08common file model\uff09\uff0c\u5e95\u5c42\u5177\u4f53\u7684\u6587\u4ef6\u7cfb\u7edf\u8d1f\u8d23\u5177\u4f53\u5b9e\u73b0\u8fd9\u79cd\u6587\u4ef6\u6a21\u578b\uff0c\u8d1f\u8d23\u5b8c\u6210POSIX API\u7684\u529f\u80fd\uff0c\u5e76\u6700\u7ec8\u5b9e\u73b0\u5bf9\u7269\u7406\u5b58\u50a8\u8bbe\u5907\u7684\u64cd\u4f5c\u3002<br \/>\n<div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/egonlin.com\/wp-content\/uploads\/2022\/08\/image-1666414322861.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/egonlin.com\/wp-content\/uploads\/2022\/08\/image-1666414322861.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"file\" \/><\/div><br \/>\nVFS\u8fd9\u4e00\u5c42\u5efa\u6a21\u548c\u62bd\u8c61\u662f\u6709\u5fc5\u8981\u7684\uff0c\u5982\u679c\u653e\u5728SCI\u5c42\u4f1a\u5bfc\u81f4\u64cd\u4f5c\u7cfb\u7edf\u7684\u7cfb\u7edf\u8c03\u7528\u7684\u529f\u80fd\u8fc7\u4e8e\u590d\u6742\uff0c\u6613\u51fabug\u3002\u90a3\u4e48\u5c31\u53ea\u80fd\u8ba9\u5e95\u5c42\u6587\u4ef6\u7cfb\u7edf\u90fd\u9075\u5faa\u7edf\u4e00\u5b9e\u73b0\uff0c\u8fd9\u5bf9\u4e8e\u5df2\u7ecf\u51fa\u73b0\u7684\u5404\u79cd\u5b58\u50a8\u8bbe\u5907\u6765\u8bf4\u5929\u7136\u5c31\u6709\u4e0d\u540c\u7684\u7279\u6027\uff0c\u4e5f\u662f\u65e0\u6cd5\u5b9e\u73b0\u7684\u3002\u56e0\u6b64VFS\u8fd9\u6837\u4e00\u5c42\u62bd\u8c61\u662f\u6709\u5176\u5fc5\u8981\u6027\u7684\u3002<\/p>\n<h2>2.2 Bufferd IO\u4e0eDirect IO<\/h2>\n<p>\u901a\u5e38\u6765\u8bf4\uff0c\u6587\u4ef6I\/O\u53ef\u4ee5\u5206\u4e3a\u4e24\u79cd\uff1a<\/p>\n<p>Buffer I\/O\uff1a\u5148\u5199buffer\u540e\u7531\u5185\u6838\u5f02\u6b65\u628a\u810f\u6570\u636e\u5237\u5165\u78c1\u76d8<br \/>\nDirect I\/O\uff1a\u76f4\u63a5\u5199\u5165<br \/>\n<div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/egonlin.com\/wp-content\/uploads\/2022\/08\/image-1666405312328.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/egonlin.com\/wp-content\/uploads\/2022\/08\/image-1666405312328.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"file\" \/><\/div><br \/>\n<div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/egonlin.com\/wp-content\/uploads\/2022\/08\/image-1666405319600.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/egonlin.com\/wp-content\/uploads\/2022\/08\/image-1666405319600.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"file\" \/><\/div><\/p>\n<p>Buffer I\/O\u8be6\u89e3<\/p>\n<blockquote>\n<p>Buffer I\/O\u53c8\u79f0\u7f13\u5b58I\/O\u3001\u6807\u51c6 I\/O\uff0c\u5927\u591a\u6570\u6587\u4ef6\u7cfb\u7edf\u7684\u9ed8\u8ba4 I\/O \u64cd\u4f5c\u90fd\u662f\u7f13\u5b58 I\/O\u3002 <\/p>\n<p>\u5728 Linux \u7684\u7f13\u5b58 I\/O \u673a\u5236\u4e2d\uff0c\u8fd9\u79cd\u8bbf\u95ee\u6587\u4ef6\u7684\u65b9\u5f0f\u662f\u901a\u8fc7\u4e24\u4e2a\u7cfb\u7edf\u8c03\u7528\u5b9e\u73b0\u7684\uff1aread() \u548c write()\u3002<br \/>\n(1) \u8c03\u7528read()\u65f6\uff1a<br \/>\n\u5982\u679c \u64cd\u4f5c\u7cfb\u7edf\u5185\u6838\u5730\u5740\u7a7a\u95f4\u7684\u9875\u7f13\u5b58\uff08 page cache \uff09\u6709\u6570\u636e\u5c31\u8bfb\u53d6\u51fa\u8be5\u6570\u636e\u5e76\u76f4\u63a5\u8fd4\u56de\u7ed9\u5e94\u7528\u7a0b\u5e8f\uff1b<br \/>\n\u5982\u679c\u6ca1\u6709\u5c31\u4ece\u78c1\u76d8\u8bfb\u53d6\u6570\u636e\u5230\u9875\u7f13\u5b58\u3002\u7136\u540e\u518d\u4ece\u9875\u7f13\u5b58\u62f7\u8d1d\u5230\u5e94\u7528\u7a0b\u5e8f\u7684\u5730\u5740\u7a7a\u95f4\u3002<br \/>\n(2) \u8c03\u7528write\uff08\uff09\u65f6\uff1a<br \/>\n\u6570\u636e\u4f1a\u5148\u4ece\u5e94\u7528\u7a0b\u5e8f\u7684\u5730\u5740\u7a7a\u95f4\u62f7\u8d1d\u5230 \u64cd\u4f5c\u7cfb\u7edf\u5185\u6838\u5730\u5740\u7a7a\u95f4\u7684\u9875\u7f13\u5b58\uff0c\u7136\u540e\u518d\u5199\u5165\u78c1\u76d8\u3002<br \/>\n\u6839\u636eLinux\u7684\u5ef6\u8fdf\u5199\u673a\u5236\uff0c\u5f53\u6570\u636e\u5199\u5230\u64cd\u4f5c\u7cfb\u7edf\u5185\u6838\u5730\u5740\u7a7a\u95f4\u7684\u9875\u7f13\u5b58\u5c31\u610f\u5473write\uff08\uff09\u5b8c\u6210\u4e86\uff0c\u64cd\u4f5c\u7cfb\u7edf\u4f1a\u5b9a\u671f\u5730\u5c06\u9875\u7f13\u5b58\u7684\u6570\u636e\u5237\u5230\u78c1\u76d8\u4e0a\u3002\u6240\u4ee5\u7f13\u5b58 I\/O \u6709\u4ee5\u4e0b\u8fd9\u4e9b\u4f18\u70b9\uff1a<br \/>\n\u7f13\u5b58 I\/O \u4f7f\u7528\u4e86\u64cd\u4f5c\u7cfb\u7edf\u5185\u6838\u7684\u9875\u7f13\u5b58\uff0c\u4fdd\u62a4\u4e86\u78c1\u76d8<br \/>\n\u7f13\u5b58 I\/O \u51cf\u5c11\u8bfb\u76d8\u7684\u6b21\u6570\uff0c\u63d0\u9ad8\u4e86\u8bfb\u53d6\u901f\u5ea6<\/p>\n<p>\u603b\u7684\u6765\u8bf4\uff0cBuffer I\/O\u4e3a\u4e86\u63d0\u9ad8\u8bfb\u5199\u6548\u7387\u548c\u4fdd\u62a4\u78c1\u76d8\u800c\u4f7f\u7528\u4e86\u9875\u7f13\u5b58\u673a\u5236\u3002<br \/>\n\u4e0d\u8fc7\u7531\u4e8e\u9875\u7f13\u5b58\u5904\u4e8e\u5185\u6838\u7a7a\u95f4\uff0c\u4e0d\u80fd\u88ab\u5e94\u7528\u7a0b\u5e8f\uff08\u7528\u6237\u8fdb\u7a0b\uff09\u76f4\u63a5\u5bfb\u5740\uff0c\u6240\u4ee5\u8fd8\u9700\u8981\u5c06\u9875\u7f13\u5b58\u6570\u636e\u518d\u62f7\u8d1d\u5230\u5185\u5b58\u5bf9\u5e94\u7684\u7528\u6237\u7a7a\u95f4\u4e2d\u3002\u8fd9\u6837\uff0c\u9700\u8981\u4e24\u6b21\u6570\u636e\u62f7\u8d1d\u624d\u80fd\u5b8c\u6210\u7528\u6237\u8fdb\u7a0b\u5bf9\u6570\u636e\u7684\u8bfb\u53d6\u64cd\u4f5c\u3002\u5199\u64cd\u4f5c\u4e5f\u662f\u4e00\u6837\uff0c\u5c06\u9875\u7f13\u5b58\u7684\u6570\u636e\u5199\u5165\u78c1\u76d8\u7684\u65f6\u5019\uff0c\u5fc5\u987b\u5148\u62f7\u8d1d\u5230\u5185\u6838\u7a7a\u95f4\u5bf9\u5e94\u7684\u4e3b\u5b58\uff0c\u7136\u540e\u5728\u5199\u5165\u78c1\u76d8\u4e2d\u3002<\/p>\n<p>\u56e0\u6b64\uff0cBuffer I\/O \u4e2d\u5f15\u5165\u4e00\u7c7b\u7279\u522b\u7684\u64cd\u4f5c\u53eb\u505a\u5185\u5b58\u6620\u5c04\u6587\u4ef6\uff08mmap\uff09\uff0c\u5b83\u7684\u4e0d\u540c\u70b9\u5728\u4e8e\uff0c\u4e2d\u95f4\u4f1a\u51cf\u5c11\u4e00\u5c42\u6570\u636e\u4ece\u7528\u6237\u5730\u5740\u7a7a\u95f4\u5230\u64cd\u4f5c\u7cfb\u7edf\u5730\u5740\u7a7a\u95f4\u7684\u590d\u5236\u5f00\u9500 \u3002\u4f7f\u7528mmap\u51fd\u6570\u7684\u65f6\u5019\uff0c\u4f1a\u5728\u5f53\u524d\u8fdb\u7a0b\u7684\u7528\u6237\u5730\u5740\u7a7a\u95f4\u4e2d\u5f00\u8f9f\u4e00\u5757\u5185\u5b58\uff0c\u8fd9\u5757\u5185\u5b58\u4e0e\u7cfb\u7edf\u7684\u6587\u4ef6\u8fdb\u884c\u6620\u5c04\u3002\u5bf9\u5176\u7684\u8bfb\u53d6\u548c\u5199\u5165\uff0c\u4f1a\u8f6c\u5316\u4e3a\u5bf9\u76f8\u5e94\u6587\u4ef6\u7684\u64cd\u4f5c\u3002 \u5e76\u4e14\uff0c\u5728\u8fdb\u7a0b\u9000\u51fa\u7684\u65f6\u5019\uff0c\u4f1a\u5c06\u53d8\u5316\u7684\u5185\u5bb9\uff08\u810f\u9875\uff09\u81ea\u52a8\u56de\u5199\u5230\u5bf9\u5e94\u7684\u6587\u4ef6\u91cc\u9762\u3002<\/p>\n<\/blockquote>\n<p>Direct I\/O\u8be6\u89e3<\/p>\n<blockquote>\n<p>\u51e1\u662f\u901a\u8fc7\u76f4\u63a5 I\/O \u65b9\u5f0f\u8fdb\u884c\u6570\u636e\u4f20\u8f93\uff0c\u6570\u636e\u5747\u76f4\u63a5\u5728\u7528\u6237\u5730\u5740\u7a7a\u95f4\u7684\u7f13\u51b2\u533a\u548c\u78c1\u76d8\u4e4b\u95f4\u76f4\u63a5\u8fdb\u884c\u4f20\u8f93\uff0c\u4e2d\u95f4\u5c11\u4e86\u9875\u7f13\u5b58page Cache\u7684\u652f\u6301\u3002<br \/>\n\u867d\u7136\u8bf4\u64cd\u4f5c\u7cfb\u7edf\u5c42\u63d0\u4f9b\u7684page Cache\u7f13\u5b58\u5f80\u5f80\u4f1a\u4f7f\u5e94\u7528\u7a0b\u5e8f\u5728\u8bfb\u5199\u6570\u636e\u7684\u65f6\u5019\u83b7\u5f97\u66f4\u597d\u7684\u6027\u80fd\uff0c\u4f46\u662f\u5bf9\u4e8e\u67d0\u4e9b\u7279\u6b8a\u7684\u5e94\u7528\u7a0b\u5e8f\uff0c\u6bd4\u5982\u8bf4\u6570\u636e\u5e93\u7ba1\u7406\u7cfb\u7edf\u8fd9\u7c7b\u5e94\u7528\uff0c\u4ed6\u4eec\u66f4\u503e\u5411\u4e8e\u9009\u62e9\u4ed6\u4eec\u81ea\u5df1\u7684\u7f13\u5b58\u673a\u5236\uff0c\u56e0\u4e3a\u6570\u636e\u5e93\u7ba1\u7406\u7cfb\u7edf\u5f80\u5f80\u6bd4\u64cd\u4f5c\u7cfb\u7edf\u66f4\u4e86\u89e3\u6570\u636e\u5e93\u4e2d\u5b58\u653e\u7684\u6570\u636e\uff0c\u6570\u636e\u5e93\u7ba1\u7406\u7cfb\u7edf\u53ef\u4ee5\u63d0\u4f9b\u4e00\u79cd\u66f4\u52a0\u6709\u6548\u7684\u7f13\u5b58\u673a\u5236\u6765\u63d0\u9ad8\u6570\u636e\u5e93\u4e2d\u6570\u636e\u7684\u5b58\u53d6\u6027\u80fd\u3002<\/p>\n<p>\u4f8b\u5982\uff1aJava \u4e2d\u76ee\u524d\u662f\u6ca1\u6709\u76f4\u63a5\u652f\u6301 Direct I\/O\u7684\uff0c\u53ea\u652f\u6301Buffer I\/O\u3002\u6211\u4eec\u53ef\u4ee5\u901a\u8fc7JNA \u6765\u5b9e\u73b0\u5176\u652f\u6301\uff0clinux\u901a\u8fc7\u5c06O_DIRECT\u6807\u5fd7\u4f20\u9012\u7ed9 open\uff08\uff09\u7cfb\u7edf\u8c03\u7528\u6765\u5b9e\u73b0\u5bf9Direct I\/O \u7684\u652f\u6301\uff0c\u4e0d\u8fc7\u76f4\u63a5\u64cd\u4f5c\u78c1\u76d8\uff0c\u6240\u6709\u5199\u5165\u5185\u5b58\u5757\u6570\u91cf\u5fc5\u987b\u662f\u6587\u4ef6\u7cfb\u7edf\u5757\u5927\u5c0f\u7684\u500d\u6570\uff0c\u800c\u4e14\u8981\u4e0e\u5185\u5b58\u9875\u5927\u5c0f\u5bf9\u9f50\u3002\u8fd9\u4e9b\u5bf9\u9f50\u89c4\u5219\u53c2\u6570\u64cd\u4f5c\u6211\u4eec\u53ef\u4ee5\u4f7f\u7528JNA\u6765\u5b8c\u6210\u3002 JNA \u662f Java \u4e2d\u4e00\u79cd\u7528\u6765\u4e0e\u672c\u5730\u5171\u4eab\u5e93\u8fdb\u884c\u4e92\u64cd\u4f5c\u7684\u4fbf\u6377\u65b9\u5f0f\uff0c\u4f7f\u7528\u5b83\u53ef\u4ee5\u76f4\u63a5\u8c03\u7528\u64cd\u4f5c\u7cfb\u7edf\u672c\u5730\u5e93\u3002<\/p>\n<\/blockquote>\n<p>\u4ec0\u4e48\u662f\u810f\u6570\u636e\uff1f<\/p>\n<pre><code class=\"language-bash\">\u9488\u5bf9bufferd I\/O\uff0c\u5199\u6570\u636e\u662f\u5148\u5199\u5165\u4e86page cache\uff0c\u8fd8\u6ca1\u6765\u5f97\u53ca\u5199\u5165\u78c1\u76d8\uff0c\u8fd9\u90e8\u5206\u6570\u636e\u79f0\u4e4b\u4e3a\u810f\u6570\u636e\uff0c\u5373dirty pages\uff0c<\/code><\/pre>\n<p>\u810f\u6570\u636e\u810f\u6570\u636e\u4f55\u65f6\u4f1a\u843d\u76d8\uff1f\uff1f\uff1f<\/p>\n<pre><code class=\"language-bash\">\u5728linux\u5185\u6838\u4e2d\u4f1a\u6709\u4e13\u95e8\u7684\u5185\u6838\u7ebf\u7a0b\uff08\u6bcf\u4e2a\u78c1\u76d8\u8bbe\u5907\u5bf9\u5e94\u7684kworker\/flush\u7ebf\u7a0b\uff09\u4f1a\u5b9a\u671f\u8d1f\u8d23\u628a\u810f\u6570\u636e\u843d\u5230\u78c1\u76d8\u4e2d\u3002<\/code><\/pre>\n<p>\u56e0\u4e3abufferd IO\u7684\u8bfb\u5199\u6548\u7387\u66f4\u9ad8\uff0c\u6240\u4ee5\u5927\u591a\u6570\u573a\u666f\u4f7f\u7528\u7684\u90fd\u662f\u8be5\u6a21\u5f0f\u3002<\/p>\n<p>\u4f46\u8be5\u6a21\u5f0f\u4e0b\uff0c\u5173\u4e8e\u8bfb\u548c\u5199\u9700\u8981\u8003\u8651\u7684\u5185\u5bb9\u8fd8\u662f\u6709\u533a\u522b\u7684<\/p>\n<ul>\n<li>\n<p>1\u3001\u8bfb\u7f13\u5b58\u5728\u7edd\u5927\u591a\u6570\u60c5\u51b5\u4e0b\u662f\u6709\u76ca\u65e0\u5bb3\u7684\uff08\u7a0b\u5e8f\u53ef\u4ee5\u76f4\u63a5\u4ece<code>RAM<\/code>\u4e2d\u8bfb\u53d6\u6570\u636e\uff09\u3002<\/p>\n<\/li>\n<li>\n<p>2\u3001\u5199\u7f13\u5b58\u6bd4\u8f83\u590d\u6742<\/p>\n<ul>\n<li>\n<p>\uff081\uff09<code>Linux<\/code>\u5185\u6838\u5c06\u78c1\u76d8\u5199\u5165\u7f13\u5b58\uff0c\u8fc7\u6bb5\u65f6\u95f4\u518d\u5f02\u6b65\u5c06\u5b83\u4eec\u5237\u65b0\u5230\u78c1\u76d8\u3002\u8fd9\u5bf9\u52a0\u901f\u78c1\u76d8I\/O\u6709\u5f88\u597d\u7684\u6548\u679c\uff0c\u4f46\u662f\u5f53\u6570\u636e\u672a\u5199\u5165\u78c1\u76d8\u65f6\uff0c\u4e22\u5931\u6570\u636e\u7684\u53ef\u80fd\u6027\u4f1a\u589e\u52a0\u3002<\/p>\n<\/li>\n<li>\n<p>\uff082\uff09\u4e5f\u5b58\u5728\u7f13\u5b58\u88ab\u5199\u7206\u7684\u60c5\u51b5\u3002<\/p>\n<\/li>\n<li>\n<p>\uff083\uff09\u8fd8\u53ef\u80fd\u51fa\u73b0\u4e00\u6b21\u6027\u5f80\u78c1\u76d8\u5199\u5165\u8fc7\u591a\u6570\u636e\uff0c\u4ee5\u81f4\u4f7f\u7cfb\u7edf\u5361\u987f\u3002\u8fd9\u4e9b\u5361\u987f\u662f\u56e0\u4e3a\u7cfb\u7edf\u8ba4\u4e3a\uff0c\u7f13\u5b58\u592a\u5927\u7528\u5f02\u6b65\u7684\u65b9\u5f0f\u6765\u4e0d\u53ca\u628a\u5b83\u4eec\u90fd\u5199\u8fdb\u78c1\u76d8\uff0c\u4e8e\u662f\u5207\u6362\u5230\u540c\u6b65\u7684\u65b9\u5f0f\u5199\u5165\u3002<\/p>\n<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p>\u9488\u5bf9\u5199\u7f13\u5b58\u7684\u8fd9\u4e9b\u8bf8\u591a\u95ee\u9898\uff0c\u5982\u4f55\u89e3\u51b3\u5462\uff1f\u6211\u4eec\u6765\u770b\u51e0\u4e2a\u91cd\u8981\u7684\u5185\u5b58\u53c2\u6570<\/p>\n<h2>2.3 \u51e0\u4e2a\u91cd\u8981\u7684\u5185\u6838\u53c2\u6570<\/h2>\n<pre><code class=\"language-bash\">$ sysctl -a | grep dirty\nvm.dirty_background_bytes = 0  # \u914d\u7f6e\u8def\u5f84\uff1a\/proc\/sys\/vm\/dirty_background_bytes\nvm.dirty_background_ratio = 10 # \u914d\u7f6e\u8def\u5f84\uff1a\/proc\/sys\/vm\/dirty_background_ratio\n\nvm.dirty_bytes = 0             # \u914d\u7f6e\u8def\u5f84\uff1a\/proc\/sys\/vm\/dirty_bytes\nvm.dirty_ratio = 20            # \u914d\u7f6e\u8def\u5f84\uff1a\/proc\/sys\/vm\/dirty_ratio\n\nvm.dirty_writeback_centisecs = 500 # \u914d\u7f6e\u8def\u5f84\uff1a \/proc\/sys\/vm\/dirty_writeback_centisecs\nvm.dirty_expire_centisecs = 3000   # \u914d\u7f6e\u8def\u5f84\uff1a \/proc\/sys\/vm\/dirty_expire_centisecs \n\nvm.dirtytime_expire_seconds = 43200 # \u914d\u7f6e\u8def\u5f84\uff1a \/proc\/sys\/vm\/dirtytime_expire_seconds\n\n\u8865\u5145\uff1a\n\/proc\/sys\/vm\/dirty_*, \u5728\u5bb9\u5668\u548c\u5bbf\u4e3b\u673a\u4e0a\u662f\u4e00\u6837\u7684\uff0c\u8fd9\u4e9b\u503c\u6ca1\u6709namespace.<\/code><\/pre>\n<p>\u4e0b\u9762\u51e0\u4e2a\u5185\u6838\u53c2\u6570\uff0c\u539f\u7406\u5927\u81f4\u76f8\u540c\uff0c\u90fd\u662f\u63a7\u5236\u4ec0\u4e48\u65f6\u5019\u5c31\u5237\u4e00\u6ce2dirty page\uff0c\u9632\u6b62\u5b83\u4e00\u76f4\u589e\u957f\u628aavailable\u5185\u5b58\u5403\u6ee1<\/p>\n<ul>\n<li><code>vm.dirty_background_ratio<\/code> \u662f\u5185\u5b58\u53ef\u4ee5\u586b\u5145\u810f\u6570\u636e\u7684\u767e\u5206\u6bd4\u3002\u8fd9\u4e9b\u810f\u6570\u636e\u7a0d\u540e\u4f1a\u5199\u5165\u78c1\u76d8\uff0c<code>pdflush\/flush\/kdmflush<\/code>\u8fd9\u4e9b\u540e\u53f0\u8fdb\u7a0b\u4f1a\u7a0d\u540e\u6e05\u7406\u810f\u6570\u636e\u3002\u6bd4\u5982\uff0c\u8be5\u503c\u8bbe\u4e3a10\uff0c\u90a3\u4e48\u6211\u670932G\u5185\u5b58\uff0c\u5219\u5141\u8bb8\u67093.2G\u7684\u810f\u6570\u636e\u5f85\u5728\u5185\u5b58\u91cc\uff0c\u8d85\u8fc73.2G\u7684\u8bdd\u5c31\u4f1a\u6709\u540e\u53f0\u8fdb\u7a0b\u6765\u6e05\u7406\u3002<\/li>\n<li><code>vm.dirty_ratio<\/code>\u662f\u53ef\u4ee5\u7528\u810f\u6570\u636e\u586b\u5145\u7684\u7edd\u5bf9\u6700\u5927\u7cfb\u7edf\u5185\u5b58\u91cf\uff0c\u5f53\u5185\u5b58\u810f\u6570\u636e\u91cf\u5230\u8fbe\u6b64\u70b9\u65f6\uff0c\u5fc5\u987b\u5c06\u6240\u6709\u810f\u6570\u636e\u63d0\u4ea4\u5230\u78c1\u76d8\uff0c\u540c\u65f6\u6240\u6709\u65b0\u7684buffered<code>I\/O<\/code>\u5757\u90fd\u4f1a\u88ab\u963b\u585e\uff0c\u76f4\u5230\u810f\u6570\u636e\u88ab\u5199\u5165\u78c1\u76d8\u3002\u8fd9\u901a\u5e38\u662f\u957f<code>I\/O<\/code>\u5361\u987f\u7684\u539f\u56e0\uff0c\u4f46\u8fd9\u4e5f\u662f\u4fdd\u8bc1\u5185\u5b58\u4e2d\u4e0d\u4f1a\u5b58\u5728\u8fc7\u91cf\u810f\u6570\u636e\u7684\u4fdd\u62a4\u673a\u5236\u3002<\/li>\n<li>\u53c2\u6570\u4e00\u4e0e\u4e8c\u7684\u53e6\u5916\u4e00\u79cd\u5199\u6cd5\uff1a<code>vm.dirty_background_bytes<\/code>\u548c<code>vm.dirty_bytes<\/code>\u662f\u53e6\u4e00\u79cd\u6307\u5b9a\u8fd9\u4e9b\u53c2\u6570\u7684\u65b9\u6cd5\u3002\u5982\u679c\u8bbe\u7f6e<code>_bytes<\/code>\u7248\u672c\uff0c\u5219<code>_ratio<\/code>\u7248\u672c\u5c06\u53d8\u4e3a0\uff0c\u53cd\u4e4b\u4ea6\u7136\u3002<\/li>\n<li><code>vm.dirty_writeback_centisecs<\/code> \u6307\u5b9a\u9ed8\u8ba4\u591a\u957f\u65f6\u95f4 <code>pdflush\/flush\/kdmflush<\/code> \u8fd9\u4e9b\u8fdb\u7a0b\u4f1a\u5524\u9192\u4e00\u6b21\uff0c\u7136\u540e\u6765\u68c0\u67e5\u662f\u5426\u6709\u7f13\u5b58\u9700\u8981\u6e05\u7406\u3002<\/li>\n<li><code>vm.dirty_expire_centisecs<\/code> \u6307\u5b9a\u810f\u6570\u636e\u80fd\u5b58\u6d3b\u7684\u65f6\u95f4\u3002\u5728\u8fd9\u91cc\u5b83\u7684\u503c\u662f30\u79d2\u3002\u5f53 <code>pdflush\/flush\/kdmflush<\/code> \u5728\u8fd0\u884c\u7684\u65f6\u5019\uff0c\u4ed6\u4eec\u4f1a\u68c0\u67e5\u662f\u5426\u6709\u6570\u636e\u8d85\u8fc7\u8fd9\u4e2a\u65f6\u9650\uff0c\u5982\u679c\u8d85\u8fc7\u5219\u4f1a\u628a\u5b83\u5f02\u6b65\u5730\u5199\u5230\u78c1\u76d8\u4e2d\u3002\u6bd5\u7adf\u6570\u636e\u5728\u5185\u5b58\u91cc\u5f85\u592a\u4e45\u4e5f\u4f1a\u6709\u4e22\u5931\u98ce\u9669\u3002<\/li>\n<li>dirtytime_expire_seconds\uff1a\u9ed8\u8ba4\u503c12 <em> 60 <\/em> 60\uff0c\u537312\u5c0f\u65f6\u3002\u4e00\u4e2ainode\u572812\u5c0f\u65f6\u5185\u672a\u5b58\u5728\u4efb\u4f55\u66f4\u65b0\uff0c\u5219\u5f88\u53ef\u80fd\u5176\u65f6\u95f4\u6233\u5728\u8fc7\u53bb\u768412\u5c0f\u65f6\u5185\u5b58\u5728\u8fc7\u53d8\u66f4\uff0c\u6bd4\u5982lazy\u65b9\u5f0f\u66f4\u65b0\u3002\u56e0\u6b64\u7cfb\u7edf\u9ed8\u8ba4\u4ee512\u5c0f\u65f6\u4e3a\u5468\u671f\u7684\u5f3a\u5236\u67e5\u770binode\u662f\u5426\u5b58\u5728\u65f6\u95f4\u6233\u53d8\u66f4\uff0c\u907f\u514d\u6587\u4ef6\u65f6\u95f4\u6233\u66f4\u65b0\u8fc7\u4e8e\u8fdf\u6ede\u3002<\/li>\n<\/ul>\n<p>\u5982\u4f55\u7406\u89e3\u4e0a\u8ff0\u53c2\u6570\u5462\uff1f\uff1f\uff1f<\/p>\n<p>\u810f\u6570\u636e\u5360\u7528\u6bd4\u4f8b=\u7b49\u4e8e dirty pages \u7684\u5185\u5b58 \/ \u8282\u70b9\u53ef\u7528\u5185\u5b58 *100%\uff0c\u4e0b\u9762\u7b80\u79f0A<\/p>\n<pre><code class=\"language-bash\">ps:\n\u53ef\u7528\u5185\u5b58\u53ef\u4ee5\u7406\u89e3\u4e3a\u6267\u884cfree\u547d\u4ee4\u8f93\u51fa\u7684&quot;available&quot; \u5185\u5b58\u3002<\/code><\/pre>\n<p>\u6211\u4eec\u53ef\u4ee5\u628a\u6574\u4e2abuffer\u7a7a\u95f4\u5f53\u6210\u4e00\u4e2a\u6c34\u6876<br \/>\n\/proc\/sys\/vm\/dirty_background_ratio\u5982\u679c\u4e3a50\uff0c\u4ee3\u8868\u6c34\u76db\u653e\u5230\u4e00\u4e2a\u534a\uff0c\u5c31\u7acb\u523b\u5f00\u95f8\u653e\u6c34\uff0c\u4f46\u662f\u4f46\u662f\u4f46\u662f\uff0c\u9700\u8981\u6ce8\u610f\u7684\u662f<br \/>\n\u4f60\u5728\u653e\u6c34\u7684\u65f6\u5019\uff0c\u540c\u65f6\u53ef\u80fd\u6709\u6c34\u8fdb\u5165\uff0c\u800c\u6ce8\u6c34\u7684\u901f\u5ea6\u662f\u6709\u53ef\u80fd\u8d85\u8fc7\u653e\u6c34\u7684\u901f\u5ea6<br \/>\n\u6240\u4ee5\u6709\u53ef\u80fd\u51fa\u73b0\u7684\u4e00\u4e2a\u73b0\u8c61\u5c31\u662f\uff0cA\u503c\u8d85\u8fc7\u4e86dirty_background_ratio\u503c\uff0clinux\u5185\u6838\u5f00\u59cb\u4e0d\u505c\u5730\u653e\u6c34\uff0c\u653e\u6c34\u7684\u76ee\u7684\u662f\u4e3a\u4e86\u8ba9A\u964d\u4e0b\u6765\uff0c\u4f46\u662f\u56e0\u4e3a<br \/>\n\u6ce8\u6c34\u901f\u5ea6\u5927\u4e8e\u653e\u6c34\u901f\u5ea6\uff0c\u800c\u51fa\u73b0\uff0cA\u4e0d\u964d\u53cd\u589e<\/p>\n<p>\u80fd\u8ba9\u5b83\u589e\u6ee1\u5417\uff1f\uff1f\uff1f\u80af\u5b9a\u4e0d\u80fd\uff0c\u8fd9\u5c31\u9700\u8981\u6709\u53e6\u5916\u4e00\u4e2a\u53c2\u6570\u6765\u9650\u5236\uff0c\u5982\u679c\u6ce8\u6c34\u7684\u901f\u5ea6\u5b9e\u5728\u592a\u79bb\u8c31\u4e86\uff0c\u90a3\u4f60\u5c31\u522b\u6ce8\uff0c\u4f60\u539f\u5730\u505c\u6b62\uff0c\u53ef\u522b\u771f\u522b\u628a\u5185\u5b58\u5403\u6ee1\u4e86<br \/>\n\u7b49\u653e\u6c34\u653e\u5230\u5b89\u5168\u7ebf\u4f60\u518d\u7ee7\u7eed\u6ce8\u6c34<\/p>\n<p>\u8fd9\u5c31\u662fdirty_radio\uff0c\u63a7\u5236\u6700\u5927\u6c34\u4f4d\uff0c\u4e00\u65e6\u8fbe\u5230\u8fd9\u4e2a\u6700\u5927\u6c34\u4f4d\uff0c\u6240\u6709\u7684buffer I\/O\u5199\u6587\u4ef6\u64cd\u4f5c\u90fd\u4f1a\u88ab\u963b\u585e\u4f4f\uff0c\u76f4\u5230\u5b83\u5199\u7684\u6570\u636e\u9875\u90fd\u5199\u5165\u78c1\u76d8\u4e3a\u6b62<br \/>\n\u6bd4\u5982dirty_background_ratio\u8bbe\u4e3a50\uff0c\u800cdirty_radio\u8bbe\u4e3a60\uff0cA\u503c\u8d85\u8fc7\u4e8650\u5219\u5f00\u59cb\u6cc4\u6d2a\uff0c\u4f46\u6cc4\u7684\u540c\u65f6\u53ef\u80fd\u4e5f\u5728\u6ce8\u6c34\uff0c\u6cc4\u7684\u6ca1\u6709\u6ce8\u7684\u5feb\uff0c\u4ee5\u81f3\u4e8e\u6c34\u4f4d\u6da8\u5230\u4e8660\uff0c\u5373\u8fbe\u5230\u4e86dirty_radio\u7684\u503c\uff0c\u90a3\u4e48\u5c31\u4f1a\u7981\u6b62\u6ce8\u6c34\uff0c\u963b\u585e\u4f4f\uff0c\u76f4\u5230\u810f\u6570\u636e\u88ab\u5199\u5165\u78c1\u76d8\u3002\u8fd9\u901a\u5e38\u662f\u957f<code>I\/O<\/code>\u5361\u987f\u7684\u539f\u56e0\uff0c\u4f46\u8fd9\u4e5f\u662f\u4fdd\u8bc1\u5185\u5b58\u4e2d\u4e0d\u4f1a\u5b58\u5728\u8fc7\u91cf\u810f\u6570\u636e\u7684\u4fdd\u62a4\u673a\u5236\u3002<\/p>\n<p>\u6709\u6ca1\u6709\u53ef\u80fdA\u6c38\u8fdc\u6ca1\u6709\u8d85\u8fc7dirty_background_ratio \uff0c\u4e5f\u6ca1\u6709\u8d85\u8fc7dirty_ratio\uff0c\u90a3\u4e48\u810f\u6570\u636e\u5c31\u4e0d\u5f80\u786c\u76d8\u5237\u4e86\u5417\uff0c\u80af\u5b9a\u4e0d\u884c\uff0c\u65ad\u7535\u6570\u636e\u5c31\u6ca1\u4e86\u554a\uff0c\u800c\u4e14\u957f\u671f\u4e0d\u5237\u662f\u8981\u95f9\u54ea\u6837\uff0c\u5199\u5b8c\u4e86\u4e4b\u540e\u5f88\u957f\u4e00\u6bb5\u65f6\u95f4\u7528\u6237\u5374\u53d1\u73b0\u78c1\u76d8\u6ca1\u6709\u8fd9\u53ef\u4e0d\u884c<br \/>\n\u8fd9\u5c31\u9700\u8981\u7528\u5230\u4e0b\u9762\u7684\u5185\u6838\u53c2\u6570\uff0c\u56fa\u5b9a\u65f6\u95f4\u6765\u5237\u65b0<\/p>\n<p>\u8fd9\u5c31\u9700\u8981\u7528\u5230\u53c2\u6570dirty_writeback_centisecs\uff1a\u9ed8\u8ba4\u503c\u4e3a500\uff0c\u5355\u4f4d\u4e3a1\/100\u79d2\uff0c\u6240\u4ee5\u9ed8\u8ba4\u4ee3\u88685\u79d2\u5524\u9192\u5185\u6838\u7684flush\u7ebf\u7a0b\u6765\u5904\u7406dirty pages<\/p>\n<p>\u53e6\u5916\uff0c\u4e3a\u4e86\u9632\u6b62\u4e00\u4e9b\u810f\u6570\u636e\u5728\u5185\u5b58\u4e2d\u505c\u7559\u65f6\u95f4\u8fc7\u4e45\uff0c\u5c31\u9700\u8981\u7528\u5230\u5185\u6838\u53c2\u6570dirty_expire_centisecs\uff1a\u4e0e\u4e0a\u9762\u4e00\u6837\u90fd\u662f\u4ee5\u767e\u5206\u4e4b\u4e00\u79d2\u4e3a\u5355\u4f4d\uff0c\u6240\u4ee5\u9ed8\u8ba4\u4e3a30s\uff0c\u6307\u7684\u662fdirty page \u5728\u5185\u5b58\u4e2d\u5b58\u653e\u7684\u6700\u957f\u65f6\u95f4\uff0c\u5982\u679c\u4e00\u4e2a dirty page \u8d85\u8fc7\u8fd9\u91cc\u5b9a\u4e49\u7684\u65f6\u95f4\uff0c\u90a3\u4e48\u5185\u6838\u7684 flush \u7ebf\u7a0b\u4e5f\u4f1a\u628a\u8fd9\u4e2a\u9875\u9762\u5199\u5165\u78c1\u76d8<\/p>\n<h2>2.4 \u67e5\u770b\u810f\u6570\u636e<\/h2>\n<p><\/p><div id=\"rml_readmorelogin_placeholder\" style=\"position:relative;\"><div id=\"rml_fade_content\" style=\"position: absolute;\r\ntop:-10em;\r\nwidth:100%;\r\nheight:10em;\r\nbackground: -webkit-linear-gradient(rgba(255, 255, 255, 0) 0%,#ffffff 100%);\r\nbackground-image: -moz-linear-gradient(rgba(255, 255, 255, 0) 0%,#ffffff 100%);\r\nbackground-image: -o-linear-gradient(rgba(255, 255, 255, 0) 0%,#ffffff 100%);\r\nbackground-image: linear-gradient(rgba(255, 255, 255, 0) 0%,#ffffff 100%);\r\nbackground-image: -ms-linear-gradient(rgba(255, 255, 255, 0) 0%,#ffffff 100%);\"><\/div><div class=\"wpf-controller aru_rml_from_in_post\" style=\"background-color:#eeeeee;border:5px solid #cce6ff;\" id=\"ARU_ReadMoreLogin_ReadMoreLoginController\"><h2 id=\"Header\">\u67e5\u770b\u66f4\u591a<\/h2><div id=\"Message\"><p>\u8054\u7cfb\u7ba1\u7406\u5458\u5fae\u4fe1tutu19192010\uff0c\u6ce8\u518c\u8d26\u53f7<\/p>\n<\/div><div id=\"StatusBarHeader\"><\/div><form id=\"ARU_ReadMoreLogin_ReadMoreLoginController\"><input name=\"post_id\" value=\"7424\" type=\"hidden\"\/><input name=\"_init_callback\" value=\"InitLogin\" type=\"hidden\"\/><input name=\"post_id\" value=\"7424\" type=\"hidden\"\/><input name=\"rt_ype\" value=\"1\" type=\"hidden\"\/><input name=\"nonce\" value=\"9ffff92025\" type=\"hidden\"\/><input name=\"_wpnonce\" value=\"7755f0f36d\" type=\"hidden\"\/><input name=\"_controller\" value=\"ARU_ReadMoreLogin\\ReadMoreLoginController\" type=\"hidden\"\/><input name=\"_proxy_controller\" value=\"ARU_ReadMoreLogin\\ReadMoreLoginController\" type=\"hidden\"\/><input name=\"_view\" value=\"ARU_ReadMoreLogin\\ReadMoreLoginView\" type=\"hidden\"\/><table class=\"wpf-table-placeholder\"><tbody class=\"wpf-table-placeholder\"><tr class=\"wpf-table-placeholder\"><td class=\"wpf-table-placeholder-input\" width=\"400px\"><table class=\"wpf-table-placeholder\"><tbody class=\"wpf-table-placeholder\"><tr class=\"wpf-table-placeholder\"><th class=\"wpf-table-placeholder-input\"><label class=\"wpf-label\">Username:<\/label><\/th><\/tr><tr class=\"wpf-table-placeholder\"><td class=\"wpf-table-placeholder-input\"><input class=\"regular-text text_input\" name=\"username\" value=\"\" type=\"text\"\/><\/td><\/tr><tr class=\"wpf-table-placeholder\"><th class=\"wpf-table-placeholder-input\"><label class=\"wpf-label\">Password:<\/label><\/th><\/tr><tr class=\"wpf-table-placeholder\"><td class=\"wpf-table-placeholder-input\"><input class=\"regular-text text_input\" name=\"password\" value=\"\" type=\"password\"\/><\/td><\/tr><\/tbody><\/table><p class=\"wpf-table-placeholder submit\"><button class=\"wp_plugin_framework_ajax_button\" type=\"button\" style=\"background-color:#4D90FE;;color:#ffffff;;border:1px solid #3079ed;\" name=\"_event\" value=\"ButtonLogin\">Log in<\/button><\/p><\/td><td class=\"wpf-table-placeholder-input\"><\/td><\/tr><\/tbody><\/table><\/form><div id=\"ButtonStartRegister\"><a href=\"https:\/\/egonlin.com\/wp-login.php?action=register\">Register<\/a><\/div><div id=\"Link1\"><a href=\"https:\/\/egonlin.com\/wp-login.php?action=lostpassword\">Forgotten username or password?<\/a><\/div><div id=\"StatusBarFooter\"><\/div><\/div><\/div><div id=aru_remaining_content><\/div>","protected":false},"excerpt":{"rendered":"<p>\u4e00 \u5f15\u5165\u95ee\u9898 1\u3001\u601d\u8003\u4e00\u4e2a\u95ee\u9898 \u6709\u4e00\u4e2a\u5bb9\u5668\uff0c\u91cc\u9762\u8fd0\u884c\u7684\u8fdb\u7a0b\u9700\u8981\u5199\u4e00\u4e2a10G\u7684\u6587\u4ef6\uff0c\u5177\u4f53\u662f\u5982\u4f55\u5199\u7684\u5462? \u4ece\u6e90\u6587\u4ef6 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