{"id":52215,"date":"2024-12-03T15:18:16","date_gmt":"2024-12-03T07:18:16","guid":{"rendered":"https:\/\/fwq.ai\/blog\/52215\/"},"modified":"2024-12-03T15:18:16","modified_gmt":"2024-12-03T07:18:16","slug":"linux%e9%a9%b1%e5%8a%a8%e7%a8%8b%e5%ba%8f%e8%bf%90%e8%a1%8c%e7%a9%ba%e9%97%b4%e6%98%af%e4%bb%80%e4%b9%88","status":"publish","type":"post","link":"https:\/\/fwq.ai\/blog\/52215\/","title":{"rendered":"linux\u9a71\u52a8\u7a0b\u5e8f\u8fd0\u884c\u7a7a\u95f4\u662f\u4ec0\u4e48"},"content":{"rendered":"

<\/b> <\/p>\n

linux\u9a71\u52a8\u7a0b\u5e8f\u8fd0\u884c\u7a7a\u95f4\u662f\u4ec0\u4e48<\/h1>\n

\u6587\u7ae0\u5c0f\u767d\u4e00\u679a\uff0c\u6b63\u5728\u4e0d\u65ad\u5b66\u4e60\u79ef\u7d2f\u77e5\u8bc6\uff0c\u73b0\u5c06\u5b66\u4e60\u5230\u7684\u77e5\u8bc6\u8bb0\u5f55\u4e00\u4e0b\uff0c\u4e5f\u662f\u5c06\u6211\u7684\u6240\u5f97\u5206\u4eab\u7ed9\u5927\u5bb6\uff01\u800c\u4eca\u5929\u8fd9\u7bc7\u6587\u7ae0\u300alinux\u9a71\u52a8\u7a0b\u5e8f\u8fd0\u884c\u7a7a\u95f4\u662f\u4ec0\u4e48\u300b\u5e26\u5927\u5bb6\u6765\u4e86\u89e3\u4e00\u4e0b##content_title##\uff0c\u5e0c\u671b\u5bf9\u5927\u5bb6\u7684\u77e5\u8bc6\u79ef\u7d2f\u6709\u6240\u5e2e\u52a9\uff0c\u4ece\u800c\u5f25\u8865\u81ea\u5df1\u7684\u4e0d\u8db3\uff0c\u52a9\u529b\u5b9e\u6218\u5f00\u53d1\uff01<\/p>\n

<\/p>\n<\/p>\n

\n

linux\u9a71\u52a8\u7a0b\u5e8f\u8fd0\u884c\u5728\u201c\u5185\u6838\u201d\u7a7a\u95f4\u3002\u4e00\u822c\u60c5\u51b5\u4e0b\u9a71\u52a8\u7a0b\u5e8f\u4e2d\u90fd\u662f\u8c03\u7528kmalloc()\u6765\u7ed9\u6570\u636e\u7ed3\u6784\u5206\u914d\u5185\u5b58\uff0c\u8c03\u7528vmalloc()\u4e3a\u6d3b\u52a8\u7684\u4ea4\u6362\u533a\u5206\u914d\u6570\u636e\u7ed3\u6784\uff0c\u4e3a\u67d0\u4e9bI\/O\u9a71\u52a8\u7a0b\u5e8f\u5206\u914d\u7f13\u51b2\u533a\uff0c\u6216\u4e3a\u6a21\u5757\u5206\u914d\u7a7a\u95f4\uff1bkmalloc\u548cvmalloc\u5206\u914d\u7684\u662f\u5185\u6838\u7684\u5185\u5b58\u3002<\/p>\n<\/blockquote>\n

linux\u9a71\u52a8\u7a0b\u5e8f\u8fd0\u884c\u5728\u201c\u5185\u6838\u201d\u7a7a\u95f4\u3002<\/strong><\/p>\n

\u5bf9\u4e8e\u4e00\u822c\u7f16\u5199\u7684\u5355\u7247\u673a\u7a0b\u5e8f\u6765\u8bf4\u5e94\u7528\u7a0b\u5e8f\u548c\u9a71\u52a8\u7a0b\u5e8f\u5f80\u5f80\u662f\u6742\u7cc5\u7684\uff0c\u62e5\u6709\u4e00\u5b9a\u80fd\u529b\u6c34\u5e73\u7684\u5355\u7247\u673a\u7a0b\u5e8f\u7f16\u7a0b\u4eba\u5458\u53ef\u4ee5\u5b9e\u73b0\u5e94\u7528\u548c\u9a71\u52a8\u7684\u5206\u5c42\u3002\u800c\u5728Linux\u7cfb\u7edf\u4e2d\u5df2\u7ecf\u5f3a\u5236\u5c06\u5e94\u7528\u548c\u9a71\u52a8\u8fdb\u884c\u4e86\u5206\u5c42\u3002<\/p>\n

\u5728\u5355\u7247\u673a\u7a0b\u5e8f\u4e2d\uff0c\u5e94\u7528\u53ef\u4ee5\u76f4\u63a5\u64cd\u4f5c\u5e95\u5c42\u7684\u5bc4\u5b58\u5668\u3002\u800c\u5728Linux\u7cfb\u7edf\u4e2d\u5374\u7981\u6b62\u8fd9\u6837\u7684\u884c\u4e3a\uff0c\u4e3e\u4e2a\u4f8b\u5b50\uff1aLinux\u5e94\u7528\u7684\u7f16\u5199\u4eba\u5458\u6545\u610f\u5728\u5e94\u7528\u4e2d\u8c03\u7528\u4e86\u9a71\u52a8\u4e2d\u5173\u4e8e\u7535\u6e90\u7ba1\u7406\u7684\u9a71\u52a8\uff0c\u5173\u95ed\u4e86\u7cfb\u7edf\uff0c\u90a3\u4e0d\u5c31\u5f97\u4e0d\u507f\u5931\u4e86\uff1f<\/p>\n

\u5177\u4f53\u7684Linux\u5e94\u7528\u7a0b\u5e8f\u5bf9\u9a71\u52a8\u7684\u8c03\u7528\u5982\u56fe\u6240\u793a\uff1a<\/p>\n

\"linux\u9a71\u52a8\u7a0b\u5e8f\u8fd0\u884c\u7a7a\u95f4\u662f\u4ec0\u4e48\u63d2\u56fe\"<\/p>\n

\u5e94\u7528\u7a0b\u5e8f\u8fd0\u884c\u5728\u7528\u6237\u7a7a\u95f4\uff0c\u9a71\u52a8\u7a0b\u5e8f\u8fd0\u884c\u5728\u5185\u6838\u7a7a\u95f4\u3002\u5904\u4e8e\u7528\u6237\u7a7a\u95f4\u5e94\u7528\u7a0b\u5e8f\u5982\u679c\u60f3\u8981\u5b9e\u73b0\u5bf9\u5185\u6838\u7684\u64cd\u4f5c\uff0c\u5fc5\u987b\u7ecf\u8fc7\u4e00\u79cd”\u7cfb\u7edf\u8c03\u7528”\u7684\u65b9\u6cd5\uff0c\u5b9e\u73b0\u4ece\u7528\u6237\u7a7a\u95f4\u8fdb\u5165\u5185\u6838\u7a7a\u95f4\uff0c\u5b9e\u73b0\u5bf9\u5e95\u5c42\u7684\u64cd\u4f5c\u3002<\/p>\n

Linux\u4e2d\u7684\u5185\u6838\u7a7a\u95f4<\/strong><\/h3>\n

\u5185\u6838\u4e5f\u662f\u7a0b\u5e8f\uff0c\u4e5f\u5e94\u8be5\u5177\u6709\u81ea\u5df1\u7684\u865a\u5b58\u7a7a\u95f4\uff0c\u4f46\u662f\u4f5c\u4e3a\u4e00\u79cd\u4e3a\u7528\u6237\u7a0b\u5e8f\u670d\u52a1\u7684\u7a0b\u5e8f\uff0c\u5185\u6838\u7a7a\u95f4\u6709\u5b83\u81ea\u5df1\u7684\u7279\u70b9\u3002<\/p>\n

\u5185\u6838\u7a7a\u95f4\u4e0e\u7528\u6237\u7a7a\u95f4\u7684\u5173\u7cfb<\/strong><\/p>\n

\u5728\u4e00\u4e2a32\u4f4d\u7cfb\u7edf\u4e2d\uff0c\u4e00\u4e2a\u7a0b\u5e8f\u7684\u865a\u62df\u7a7a\u95f4\u6700\u5927\u53ef\u4ee5\u662f4GB\uff0c\u90a3\u4e48\u6700\u76f4\u63a5\u7684\u505a\u6cd5\u5c31\u662f\uff0c\u628a\u5185\u6838\u4e5f\u770b\u4f5c\u662f\u4e00\u4e2a\u7a0b\u5e8f\uff0c\u4f7f\u5b83\u548c\u5176\u4ed6\u7a0b\u5e8f\u4e00\u6837\u4e5f\u5177\u67094GB\u7a7a\u95f4\u3002\u4f46\u662f\u8fd9\u79cd\u505a\u6cd5\u4f1a\u4f7f\u7cfb\u7edf\u4e0d\u65ad\u7684\u5207\u6362\u7528\u6237\u7a0b\u5e8f\u7684\u9875\u8868\u548c\u5185\u6838\u9875\u8868\uff0c\u4ee5\u81f4\u5f71\u54cd\u8ba1\u7b97\u673a\u7684\u6548\u7387\u3002\u89e3\u51b3\u8fd9\u4e2a\u95ee\u9898\u7684\u6700\u597d\u505a\u6cd5\u5c31\u662f\u628a4GB\u7a7a\u95f4\u5206\u6210\u4e24\u4e2a\u90e8\u5206\uff1a\u4e00\u90e8\u5206\u4e3a\u7528\u6237\u7a7a\u95f4\uff0c\u53e6\u4e00\u90e8\u5206\u4e3a\u5185\u6838\u7a7a\u95f4\uff0c\u8fd9\u6837\u5c31\u53ef\u4ee5\u4fdd\u8bc1\u5185\u6838\u7a7a\u95f4\u56fa\u5b9a\u4e0d\u53d8\uff0c\u800c\u5f53\u7a0b\u5e8f\u5207\u6362\u65f6\uff0c\u6539\u53d8\u7684\u4ec5\u662f\u7a0b\u5e8f\u7684\u9875\u8868\u3002\u8fd9\u79cd\u505a\u6cd5\u7684\u552f\u4e00\u7f3a\u70b9\u4fbf\u662f\u5185\u6838\u7a7a\u95f4\u548c\u7528\u6237\u7a7a\u95f4\u5747\u53d8\u5c0f\u4e86\u3002<\/strong><\/p>\n

\u4f8b\u5982\uff1a\u5728i386\u8fd9\u79cd32\u4f4d\u7684\u786c\u4ef6\u5e73\u53f0\u4e0a\uff0cLinux\u5728\u6587\u4ef6page.h\u4e2d\u5b9a\u4e49\u4e86\u4e00\u4e2a\u5e38\u91cfPAGE_OFFSET\uff1a<\/p>\n

#ifdef CONFIG_MMU\n#define __PAGE_OFFSET  (0xC0000000)        \/\/0xC0000000\u4e3a3GB\n#else\n#define __PAGE_OFFSET  (0x00000000)\n#endif\n\n#define PAGE_OFFSET\t\t((unsigned long)__PAGE_OFFSET)<\/pre>\n
Linux\u4ee5PAGE_OFFSET\u4e3a\u754c\u5c064GB\u7684\u865a\u62df\u5185\u5b58\u7a7a\u95f4\u5206\u6210\u4e86\u4e24\u90e8\u5206\uff1a\u5730\u57400~3G-1\u8fd9\u6bb5\u4f4e\u5730\u5740\u7a7a\u95f4\u4e3a\u7528\u6237\u7a7a\u95f4\uff0c\u5927\u5c0f\u4e3a3GB\uff1b\u5730\u57403GB~4GB-1\u8fd9\u6bb5\u9ad8\u5730\u5740\u7a7a\u95f4\u4e3a\u5185\u6838\u7a7a\u95f4\uff0c\u5927\u5c0f\u4e3a1GB\u3002<\/strong><\/p>\n
\u5f53\u7cfb\u7edf\u4e2d\u8fd0\u884c\u591a\u4e2a\u7a0b\u5e8f\u65f6\uff0c\u591a\u4e2a\u7528\u6237\u7a7a\u95f4\u4e0e\u5185\u6838\u7a7a\u95f4\u7684\u5173\u7cfb\u53ef\u4ee5\u8868\u793a\u5982\u4e0b\u56fe\uff1a<\/p>\n
\"linux\u9a71\u52a8\u7a0b\u5e8f\u8fd0\u884c\u7a7a\u95f4\u662f\u4ec0\u4e48\u63d2\u56fe1\"<\/p>\n
\u5982\u56fe\u4e2d\u6240\u793a\uff0c\u7a0b\u5e8f1\u30012\u2026\u2026n\u5171\u4eab\u5185\u6838\u7a7a\u95f4\u3002\u5f53\u7136\uff0c\u8fd9\u91cc\u7684\u5171\u4eab\u6307\u5f97\u662f\u5206\u65f6\u5171\u4eab\uff0c\u56e0\u4e3a\u5728\u4efb\u4f55\u65f6\u523b\uff0c\u5bf9\u4e8e\u5355\u6838\u5904\u7406\u5668\u7cfb\u7edf\u6765\u8bf4\uff0c\u53ea\u80fd\u6709\u4e00\u4e2a\u7a0b\u5e8f\u5728\u8fd0\u884c\u3002<\/p>\n
\u5185\u6838\u7a7a\u95f4\u7684\u603b\u4f53\u5e03\u5c40<\/strong><\/p>\n
Linux\u5728\u53d1\u5c55\u8fc7\u7a0b\u4e2d\uff0c\u968f\u7740\u786c\u4ef6\u8bbe\u5907\u7684\u66f4\u65b0\u548c\u6280\u672f\u6c34\u5e73\u7684\u63d0\u9ad8\uff0c\u5176\u5185\u6838\u7a7a\u95f4\u5e03\u5c40\u7684\u53d1\u5c55\u4e5f\u662f\u4e00\u79cd\u4e0d\u65ad\u6253\u8865\u4e01\u7684\u65b9\u5f0f\u3002\u8fd9\u6837\u7684\u540e\u679c\u5c31\u662f\u4f7f\u5f97\u5185\u6838\u7a7a\u95f4\u88ab\u5206\u6210\u4e0d\u540c\u7684\u51e0\u4e2a\u533a\u57df\uff0c\u800c\u4e14\u5728\u4e0d\u540c\u7684\u533a\u57df\u5177\u6709\u4e0d\u540c\u7684\u6620\u5c04\u65b9\u5f0f\u3002\u901a\u5e38\uff0c\u4eba\u4eec\u8ba4\u4e3aLinux\u5185\u6838\u7a7a\u95f4\u6709\u4e09\u4e2a\u533a\u57df\uff0c\u5373DMA\u533a\uff08ZONE_DMA\uff09\u3001\u666e\u901a\u533a\uff08ZONE_NORMAL\uff09\u548c\u9ad8\u7aef\u5185\u5b58\u533a\uff08ZONE_HIGHMEM\uff09\u3002<\/strong><\/p>\n
\u5b9e\u9645\u7269\u7406\u5185\u5b58\u8f83\u5c0f\u65f6\u5185\u6838\u7a7a\u95f4\u7684\u76f4\u63a5\u6620\u5c04<\/strong><\/h4>\n
\u65e9\u671f\u8ba1\u7b97\u673a\u5b9e\u9645\u914d\u7f6e\u7684\u7269\u7406\u5185\u5b58\u901a\u5e38\u53ea\u6709\u51e0MB\uff0c\u6240\u4ee5\u4e3a\u4e86\u63d0\u9ad8\u5185\u6838\u901a\u8fc7\u865a\u62df\u5730\u5740\u8bbf\u95ee\u7269\u7406\u5730\u5740\u5185\u5b58\u7684\u901f\u5ea6\uff0c\u5185\u6838\u7a7a\u95f4\u7684\u865a\u62df\u5730\u5740\u4e0e\u7269\u7406\u5185\u5b58\u5730\u5740\u91c7\u7528\u4e86\u4e00\u79cd\u4ece\u4f4e\u5730\u5740\u5411\u9ad8\u5730\u5740\u4f9d\u6b21\u4e00\u4e00\u5bf9\u5e94\u7684\u56fa\u5b9a\u6620\u5c04\u65b9\u5f0f\uff0c<\/strong>\u5982\u4e0b\u56fe\u6240\u793a\uff1a<\/p>\n
\"linux\u9a71\u52a8\u7a0b\u5e8f\u8fd0\u884c\u7a7a\u95f4\u662f\u4ec0\u4e48\u63d2\u56fe2\"<\/p>\n
\u53ef\u4ee5\u770b\u5230\uff0c\u8fd9\u79cd\u56fa\u5b9a\u6620\u5c04\u65b9\u5f0f\u4f7f\u5f97\u865a\u62df\u5730\u5740\u4e0e\u7269\u7406\u5730\u5740\u7684\u5173\u7cfb\u53d8\u5f97\u5f88\u7b80\u5355\uff0c\u5373\u5185\u6838\u865a\u62df\u5730\u5740\u4e0e\u5b9e\u9645\u7269\u7406\u5730\u5740\u53ea\u5728\u6570\u503c\u4e0a\u76f8\u5dee\u4e00\u4e2a\u56fa\u5b9a\u7684\u504f\u79fb\u91cfPAGE_OFFSET\uff0c\u6240\u4ee5\u5f53\u5185\u6838\u4f7f\u7528\u865a\u62df\u5730\u5740\u8bbf\u95ee\u7269\u7406\u9875\u6846\u65f6\uff0c\u53ea\u9700\u5728\u865a\u62df\u5730\u5740\u4e0a\u51cf\u53bbPAGE_OFFSET\u5373\u53ef\u5f97\u5230\u5b9e\u9645\u7269\u7406\u5730\u5740\uff0c\u6bd4\u4f7f\u7528\u9875\u8868\u7684\u65b9\u5f0f\u8981\u5feb\u5f97\u591a\uff01<\/strong><\/p>\n
\u7531\u4e8e\u8fd9\u79cd\u505a\u6cd5\u51e0\u4e4e\u5c31\u662f\u76f4\u63a5\u4f7f\u7528\u7269\u7406\u5730\u5740\uff0c\u6240\u4ee5\u8fd9\u79cd\u6309\u56fa\u5b9a\u6620\u5c04\u65b9\u5f0f\u7684\u5185\u6838\u7a7a\u95f4\u4e5f\u5c31\u53eb\u505a\u201c\u7269\u7406\u5185\u5b58\u7a7a\u95f4\u201d\uff0c\u7b80\u79f0\u7269\u7406\u5185\u5b58\u3002\u53e6\u5916\uff0c\u7531\u4e8e\u56fa\u5b9a\u6620\u5c04\u65b9\u5f0f\u662f\u4e00\u79cd\u7ebf\u6027\u6620\u5c04\uff0c\u6240\u4ee5\u8fd9\u4e2a\u533a\u57df\u4e5f\u53eb\u505a\u7ebf\u6027\u6620\u5c04\u533a\u3002<\/strong><\/p>\n
\u5f53\u7136\uff0c\u8fd9\u79cd\u60c5\u51b5\u4e0b\uff08\u8ba1\u7b97\u673a\u5b9e\u9645\u7269\u7406\u5185\u5b58\u8f83\u5c0f\u65f6\uff09\uff0c\u5185\u6838\u56fa\u5b9a\u6620\u5c04\u7a7a\u95f4\u4ec5\u5360\u6574\u4e2a1GB\u5185\u6838\u7a7a\u95f4\u7684\u4e00\u90e8\u5206\u3002\u4f8b\u5982\uff1a\u5728\u914d\u7f6e32MB\u5b9e\u9645\u7269\u7406\u5185\u5b58\u7684x86\u8ba1\u7b97\u673a\u7cfb\u7edf\u65f6\uff0c\u5185\u6838\u7684\u56fa\u5b9a\u6620\u5c04\u533a\u4fbf\u662fPAGE_OFFSET~\uff08PAGE_OFFSET+0x02000000\uff09\u8fd9\u4e2a32MB\u7a7a\u95f4\u3002\u90a3\u4e48\u5185\u6838\u7a7a\u95f4\u5269\u4f59\u7684\u5185\u6838\u865a\u62df\u7a7a\u95f4\u600e\u4e48\u529e\u5462\uff1f<\/p>\n
\u5f53\u7136\u8fd8\u662f\u6309\u7167\u666e\u901a\u865a\u62df\u7a7a\u95f4\u7684\u7ba1\u7406\u65b9\u5f0f\uff0c\u4ee5\u9875\u8868\u7684\u975e\u7ebf\u6027\u6620\u5c04\u65b9\u5f0f\u4f7f\u7528\u7269\u7406\u5185\u5b58\u3002\u5177\u4f53\u6765\u8bf4\uff0c\u5728\u6574\u4e2a1GB\u5185\u6838\u7a7a\u95f4\u4e2d\u53bb\u9664\u56fa\u5b9a\u6620\u5c04\u533a\uff0c\u7136\u540e\u5728\u5269\u4f59\u90e8\u5206\u4e2d\u518d\u53bb\u9664\u5176\u5f00\u5934\u90e8\u5206\u7684\u4e00\u4e2a8MB\u9694\u79bb\u533a\uff0c\u4f59\u4e0b\u7684\u5c31\u662f\u6620\u5c04\u65b9\u5f0f\u4e0e\u7528\u6237\u7a7a\u95f4\u76f8\u540c\u7684\u666e\u901a\u865a\u62df\u5185\u5b58\u6620\u5c04\u533a\u3002\u5728\u8fd9\u4e2a\u533a\uff0c\u865a\u62df\u5730\u5740\u548c\u7269\u7406\u5730\u5740\u4e0d\u4ec5\u4e0d\u5b58\u5728\u56fa\u5b9a\u6620\u5c04\u5173\u7cfb\uff0c\u800c\u4e14\u901a\u8fc7\u8c03\u7528\u5185\u6838\u51fd\u6570vmalloc()\u83b7\u5f97\u52a8\u6001\u5185\u5b58\uff0c\u6545\u8fd9\u4e2a\u533a\u5c31\u88ab\u79f0\u4e3avmalloc\u5206\u914d\u533a\uff0c<\/strong>\u5982\u4e0b\u56fe\u6240\u793a\uff1a<\/p>\n
\"linux\u9a71\u52a8\u7a0b\u5e8f\u8fd0\u884c\u7a7a\u95f4\u662f\u4ec0\u4e48\u63d2\u56fe3\"<\/p>\n
\u5bf9\u4e8e\u914d\u7f6e32MB\u5b9e\u9645\u7269\u7406\u5185\u5b58\u7684x86\u8ba1\u7b97\u673a\u7cfb\u7edf\u6765\u8bf4\uff0cvmalloc\u5206\u914d\u533a\u7684\u8d77\u59cb\u4f4d\u7f6e\u4e3aPAGE_OFFSET+0x02000000+0x00800000\u3002<\/p>\n
\u8fd9\u91cc\u8bf4\u660e\u4e00\u4e0b\uff1a\u8fd9\u91cc\u8bf4\u7684\u5185\u6838\u7a7a\u95f4\u4e0e\u7269\u7406\u9875\u6846\u7684\u56fa\u5b9a\u6620\u5c04\uff0c\u5b9e\u8d28\u4e0a\u662f\u5185\u6838\u9875\u5bf9\u7269\u7406\u9875\u6846\u7684\u4e00\u79cd\u201c\u9884\u5b9a\u201d\uff0c\u5e76\u4e0d\u662f\u8bf4\u8fd9\u4e9b\u9875\u5c31\u201c\u9738\u5360\u201d\u4e86\u8fd9\u4e9b\u7269\u7406\u9875\u6846\u3002\u5373\u53ea\u6709\u5f53\u865a\u62df\u9875\u771f\u6b63\u9700\u8981\u8bbf\u95ee\u7269\u7406\u9875\u6846\u65f6\uff0c\u865a\u62df\u9875\u624d\u4e0e\u7269\u7406\u9875\u6846\u7ed1\u5b9a\u3002\u800c\u5e73\u65f6\uff0c\u5f53\u67d0\u4e2a\u7269\u7406\u9875\u6846\u4e0d\u88ab\u4e0e\u5b83\u5bf9\u5e94\u7684\u865a\u62df\u9875\u6240\u4f7f\u7528\u65f6\uff0c\u8be5\u9875\u6846\u5b8c\u5168\u53ef\u4ee5\u88ab\u7528\u6237\u7a7a\u95f4\u4ee5\u53ca\u540e\u9762\u6240\u4ecb\u7ecd\u7684\u5185\u6838kmalloc\u5206\u914d\u533a\u4f7f\u7528\u3002<\/strong><\/p>\n
\u603b\u4e4b\uff0c\u5728\u5b9e\u9645\u7269\u7406\u5185\u5b58\u8f83\u5c0f\u7684\u7cfb\u7edf\u4e2d\uff0c\u5b9e\u9645\u5185\u5b58\u7684\u5927\u5c0f\u5c31\u662f\u5185\u6838\u7a7a\u95f4\u7684\u7269\u7406\u5185\u5b58\u533a\u4e0evmalloc\u5206\u914d\u533a\u7684\u8fb9\u754c\u3002<\/p>\n
ZONE_DMA\u533a\u4e0eZONE_NORMAL\u533a<\/strong><\/h4>\n
\u5bf9\u4e8e\u6574\u4e2a1GB\u7684\u5185\u6838\u7a7a\u95f4\uff0c\u4eba\u4eec\u8fd8\u628a\u8be5\u7a7a\u95f4\u5934\u90e8\u768416MB\u53eb\u505aDMA\u533a\uff0c\u5373ZONE_DMA\u533a\uff0c\u56e0\u4e3a\u4ee5\u5f80\u786c\u4ef6\u5c06DMA\u7a7a\u95f4\u56fa\u5b9a\u5728\u4e86\u7269\u7406\u5185\u5b58\u7684\u4f4e16MB\u7a7a\u95f4\uff1b\u5176\u4f59\u533a\u5219\u53eb\u505a\u666e\u901a\u533a\uff0c\u5373ZONE_NORMAL\u3002<\/strong><\/p>\n
\u5185\u6838\u7a7a\u95f4\u7684\u9ad8\u7aef\u5185\u5b58<\/strong><\/p>\n
\u968f\u7740\u8ba1\u7b97\u673a\u6280\u672f\u7684\u53d1\u5c55\uff0c\u8ba1\u7b97\u673a\u7684\u5b9e\u9645\u7269\u7406\u5185\u5b58\u8d8a\u6765\u8d8a\u5927\uff0c\u4ece\u800c\u4f7f\u5f97\u5185\u6838\u56fa\u5b9a\u6620\u5c04\u533a\uff08\u7ebf\u6027\u533a\uff09\u4e5f\u8d8a\u6765\u8d8a\u5927\u3002<\/strong>\u663e\u7136\uff0c\u5982\u679c\u4e0d\u52a0\u4ee5\u9650\u5236\uff0c\u5f53\u5b9e\u9645\u7269\u7406\u5185\u5b58\u8fbe\u52301GB\u65f6\uff0cvmalloc\u5206\u914d\u533a\uff08\u975e\u7ebf\u6027\u533a\uff09\u5c06\u4e0d\u590d\u5b58\u5728\u3002\u4e8e\u662f\u4ee5\u524d\u5f00\u53d1\u7684\u3001\u8c03\u7528\u4e86vmalloc()\u7684\u5185\u6838\u4ee3\u7801\u4e5f\u5c31\u4e0d\u518d\u53ef\u7528\uff0c\u663e\u7136\u4e3a\u4e86\u517c\u5bb9\u65e9\u671f\u7684\u5185\u6838\u4ee3\u7801\uff0c\u8fd9\u662f\u4e0d\u80fd\u5141\u8bb8\u7684\u3002<\/p>\n
\u4e0b\u56fe\u5c31\u8868\u793a\u4e86\u8fd9\u79cd\u5185\u6838\u7a7a\u95f4\u6240\u9762\u4e34\u7684\u5c40\u9762\uff1a<\/p>\n
\"linux\u9a71\u52a8\u7a0b\u5e8f\u8fd0\u884c\u7a7a\u95f4\u662f\u4ec0\u4e48\u63d2\u56fe4\"<\/p>\n
\u663e\u7136\uff0c\u51fa\u73b0\u4e0a\u8ff0\u95ee\u9898\u7684\u539f\u56e0\u5c31\u662f\u6ca1\u6709\u9884\u6599\u5230\u5b9e\u9645\u7269\u7406\u5185\u5b58\u53ef\u4ee5\u8d85\u8fc71GB\uff0c\u56e0\u800c\u6ca1\u6709\u4e3a\u5185\u6838\u56fa\u5b9a\u6620\u5c04\u533a\u7684\u8fb9\u754c\u8bbe\u5b9a\u9650\u5236\uff0c\u800c\u4efb\u7531\u5176\u968f\u7740\u5b9e\u9645\u7269\u7406\u5185\u5b58\u7684\u589e\u5927\u800c\u589e\u5927\u3002<\/strong><\/p>\n
\u89e3\u51b3\u4e0a\u8ff0\u95ee\u9898\u7684\u65b9\u6cd5\u5c31\u662f\uff1a\u5bf9\u5185\u6838\u7a7a\u95f4\u56fa\u5b9a\u6620\u5c04\u533a\u7684\u4e0a\u9650\u52a0\u4ee5\u9650\u5236\uff0c\u4f7f\u4e4b\u4e0d\u80fd\u968f\u7740\u7269\u7406\u5185\u5b58\u7684\u589e\u52a0\u800c\u4efb\u610f\u589e\u52a0\u3002Linux\u89c4\u5b9a\uff0c\u5185\u6838\u6620\u5c04\u533a\u7684\u4e0a\u8fb9\u754c\u7684\u503c\u6700\u5927\u4e0d\u80fd\u5927\u4e8e\u4e00\u4e2a\u5c0f\u4e8e1G\u7684\u5e38\u6570high_menory\uff0c\u5f53\u5b9e\u9645\u7269\u7406\u5185\u5b58\u8f83\u5927\u65f6\uff0c\u4ee53G+high_memory\u4e3a\u8fb9\u754c\u6765\u786e\u5b9a\u7269\u7406\u5185\u5b58\u533a\u3002<\/strong><\/p>\n
\u4f8b\u5982\uff1a\u5bf9\u4e8ex86\u7cfb\u7edf\uff0chigh_memory\u7684\u503c\u4e3a896M\uff0c\u4e8e\u662f1GB\u5185\u6838\u7a7a\u95f4\u4f59\u4e0b\u7684128MB\u4e3a\u975e\u7ebf\u6027\u6620\u5c04\u533a\u3002\u8fd9\u6837\u5c31\u786e\u4fdd\u5728\u4efb\u4f55\u60c5\u51b5\u4e0b\uff0c\u5185\u6838\u90fd\u6709\u8db3\u591f\u7684\u975e\u7ebf\u6027\u6620\u5c04\u533a\u4ee5\u517c\u5bb9\u65e9\u671f\u4ee3\u7801\u5e76\u53ef\u4ee5\u6309\u666e\u901a\u865a\u5b58\u65b9\u5f0f\u8bbf\u95ee\u5b9e\u9645\u7269\u7406\u5185\u5b58\u76841GB\u4ee5\u4e0a\u7684\u7a7a\u95f4\u3002<\/p>\n
\u4e5f\u5c31\u662f\u8bf4\uff0c\u9ad8\u7aef\u5185\u5b58\u7684\u6700\u57fa\u672c\u601d\u60f3\uff1a\u501f\u4e00\u6bb5\u5730\u5740\u7a7a\u95f4\uff0c\u5efa\u7acb\u4e34\u65f6\u5730\u5740\u6620\u5c04\uff0c\u7528\u5b8c\u540e\u91ca\u653e\uff0c\u8fbe\u5230\u8fd9\u6bb5\u5730\u5740\u7a7a\u95f4\u53ef\u4ee5\u5faa\u73af\u4f7f\u7528\uff0c\u8bbf\u95ee\u6240\u6709\u7269\u7406\u5185\u5b58\u3002<\/strong>\u5f53\u8ba1\u7b97\u673a\u662f\u7269\u7406\u5185\u5b58\u8f83\u5927\u65f6\uff0c\u5185\u6838\u7a7a\u95f4\u7684\u793a\u610f\u56fe\u5982\u4e0b\uff1a<\/p>\n
\"linux\u9a71\u52a8\u7a0b\u5e8f\u8fd0\u884c\u7a7a\u95f4\u662f\u4ec0\u4e48\u63d2\u56fe5\"<\/p>\n
\u4e60\u60ef\u4e0a\uff0cLinux\u628a\u5185\u6838\u7a7a\u95f43G+high_memory~4G-1\u7684\u8fd9\u4e2a\u90e8\u5206\u53eb\u505a\u9ad8\u7aef\u5185\u5b58\u533a\uff08ZONE_HIGHMEM\uff09\u3002<\/p>\n
\u603b\u7ed3\u4e00\u4e0b\uff1a\u5728x86\u7ed3\u6784\u7684\u5185\u6838\u7a7a\u95f4\uff0c\u4e09\u79cd\u7c7b\u578b\u7684\u533a\u57df\uff08\u4ece3G\u5f00\u59cb\u8ba1\u7b97\uff09\u5982\u4e0b\uff1a<\/p>\n
    \n
  • \n
    ZONE_DMA\uff1a\u5185\u6838\u7a7a\u95f4\u5f00\u59cb\u768416MB<\/strong><\/p>\n<\/li>\n
  • \n
    ZONE_NORMAL\uff1a\u5185\u6838\u7a7a\u95f416MB~896MB\uff08\u56fa\u5b9a\u6620\u5c04\uff09<\/strong><\/p>\n<\/li>\n
  • \n
    ZONE_HIGHMEM \uff1a\u5185\u6838\u7a7a\u95f4896MB ~ \u7ed3\u675f\uff081G\uff09<\/strong><\/p>\n<\/li>\n<\/ul>\n
    \u6839\u636e\u5e94\u7528\u76ee\u6807\u4e0d\u540c\uff0c\u9ad8\u7aef\u5185\u5b58\u533a\u5206vmalloc\u533a\u3001\u53ef\u6301\u4e45\u6620\u5c04\u533a\u548c\u4e34\u65f6\u6620\u5c04\u533a\u3002<\/strong>\u5185\u6838\u7a7a\u95f4\u4e2d\u9ad8\u7aef\u5185\u5b58\u7684\u5e03\u5c40\u5982\u4e0b\u56fe\u6240\u793a\uff1a<\/p>\n
    \"linux\u9a71\u52a8\u7a0b\u5e8f\u8fd0\u884c\u7a7a\u95f4\u662f\u4ec0\u4e48\u63d2\u56fe6\"<\/p>\n
    vmalloc\u6620\u5c04\u533a<\/strong><\/h4>\n
    vmalloc\u6620\u5c04\u533a\u65f6\u9ad8\u7aef\u5185\u5b58\u7684\u4e3b\u8981\u90e8\u5206\uff0c\u8be5\u533a\u95f4\u7684\u5934\u90e8\u4e0e\u5185\u6838\u7ebf\u6027\u6620\u5c04\u7a7a\u95f4\u4e4b\u95f4\u6709\u4e00\u4e2a8MB\u7684\u9694\u79bb\u533a\uff0c\u5c3e\u90e8\u4e0e\u540e\u7eed\u7684\u53ef\u6301\u4e45\u6620\u5c04\u533a\u6709\u4e00\u4e2a4KB\u7684\u9694\u79bb\u533a\u3002<\/p>\n
    vmalloc\u6620\u5c04\u533a\u7684\u6620\u5c04\u65b9\u5f0f\u4e0e\u7528\u6237\u7a7a\u95f4\u5b8c\u5168\u76f8\u540c\uff0c\u5185\u6838\u53ef\u4ee5\u901a\u8fc7\u8c03\u7528\u51fd\u6570vmalloc()\u5728\u8fd9\u4e2a\u533a\u57df\u83b7\u5f97\u5185\u5b58\u3002\u8fd9\u4e2a\u51fd\u6570\u7684\u529f\u80fd\u76f8\u5f53\u4e8e\u7528\u6237\u7a7a\u95f4\u7684malloc()\uff0c\u6240\u63d0\u4f9b\u7684\u5185\u5b58\u7a7a\u95f4\u5728\u865a\u62df\u5730\u5740\u4e0a\u8fde\u7eed\uff08\u6ce8\u610f\uff0c\u4e0d\u4fdd\u8bc1\u7269\u7406\u5730\u5740\u8fde\u7eed\uff09\u3002<\/strong><\/p>\n
    \u53ef\u6301\u4e45\u5185\u6838\u6620\u5c04\u533a<\/strong><\/h4>\n
    \u5982\u679c\u662f\u901a\u8fc7 alloc_page() \u83b7\u5f97\u4e86\u9ad8\u7aef\u5185\u5b58\u5bf9\u5e94\u7684 page\uff0c\u5982\u4f55\u7ed9\u5b83\u627e\u4e2a\u7ebf\u6027\u7a7a\u95f4\uff1f<\/p>\n
    \u5185\u6838\u4e13\u95e8\u4e3a\u6b64\u7559\u51fa\u4e00\u5757\u7ebf\u6027\u7a7a\u95f4\uff0c\u4ecePKMAP_BASE\u5f00\u59cb\uff0c\u7528\u4e8e\u6620\u5c04\u9ad8\u7aef\u5185\u5b58\uff0c\u5c31\u662f\u53ef\u6301\u4e45\u5185\u6838\u6620\u5c04\u533a\u3002<\/p>\n
    \u5728\u53ef\u6301\u4e45\u5185\u6838\u6620\u5c04\u533a\uff0c\u53ef\u901a\u8fc7\u8c03\u7528\u51fd\u6570kmap()\u5728\u7269\u7406\u9875\u6846\u4e0e\u5185\u6838\u865a\u62df\u9875\u4e4b\u95f4\u5efa\u7acb\u957f\u671f\u6620\u5c04\u3002\u8fd9\u4e2a\u7a7a\u95f4\u901a\u5e38\u4e3a4MB\uff0c\u6700\u591a\u80fd\u6620\u5c041024\u4e2a\u9875\u6846\uff0c\u6570\u91cf\u8f83\u4e3a\u7a00\u5c11\uff0c\u6240\u4ee5\u4e3a\u4e86\u52a0\u5f3a\u9875\u6846\u7684\u5468\u8f6c\uff0c\u5e94\u53ca\u65f6\u8c03\u7528\u51fd\u6570kunmap()\u5c06\u4e0d\u518d\u4f7f\u7528\u7684\u7269\u7406\u9875\u6846\u91ca\u653e\u3002<\/strong><\/p>\n
    \u4e34\u65f6\u6620\u5c04\u533a<\/strong><\/h4>\n
    \u4e34\u65f6\u6620\u5c04\u533a\u4e5f\u53eb\u56fa\u5b9a\u6620\u5c04\u533a\u548c\u4fdd\u7559\u533a\u3002\u8be5\u533a\u4e3b\u8981\u5e94\u7528\u5728\u591a\u5904\u7406\u5668\u7cfb\u7edf\u4e2d\uff0c\u56e0\u4e3a\u5728\u8fd9\u4e2a\u533a\u57df\u6240\u83b7\u5f97\u7684\u5185\u5b58\u7a7a\u95f4\u6ca1\u6709\u6240\u4fdd\u62a4\uff0c\u6545\u6240\u83b7\u5f97\u7684\u5185\u5b58\u5fc5\u987b\u53ca\u65f6\u4f7f\u7528\uff1b\u5426\u5219\u4e00\u65e6\u6709\u65b0\u7684\u8bf7\u6c42\uff0c\u8be5\u9875\u6846\u4e0a\u7684\u5185\u5bb9\u5c31\u4f1a\u88ab\u8986\u76d6\uff0c\u6240\u4ee5\u8fd9\u4e2a\u533a\u57df\u53eb\u505a\u4e34\u65f6\u6620\u5c04\u533a\u3002<\/p>\n
    \u5173\u4e8e\u9ad8\u7aef\u5185\u5b58\u533a\u4e00\u7bc7\u5f88\u4e0d\u9519\u7684\u6587\u7ae0\uff1alinux \u7528\u6237\u7a7a\u95f4\u4e0e\u5185\u6838\u7a7a\u95f4\u2014\u2014\u9ad8\u7aef\u5185\u5b58\u8be6\u89e3\u3002<\/p>\n
    \u5185\u6838\u5185\u5b58\u5206\u914d\u4fee\u9970\u7b26gfp<\/strong><\/p>\n
    \u4e3a\u4e86\u5728\u5185\u6838\u5185\u5b58\u8bf7\u6c42\u51fd\u6570\u5bf9\u8bf7\u6c42\u8fdb\u884c\u5fc5\u8981\u7684\u8bf4\u660e\uff0cLinux\u5b9a\u4e49\u4e86\u591a\u79cd\u5185\u5b58\u5206\u914d\u4fee\u9970\u7b26gfp\u3002\u5b83\u4eec\u662f\u884c\u4e3a\u4fee\u9970\u7b26\u3001\u533a\u4fee\u9970\u7b26\u3001\u7c7b\u578b\u4fee\u9970\u7b26\u3002<\/strong><\/p>\n
    \u884c\u4e3a\u4fee\u9970\u7b26<\/strong><\/h4>\n
    \u5728\u5185\u5b58\u5206\u914d\u51fd\u6570\u4e2d\u7684\u884c\u4e3a\u4fee\u9970\u7b26\u8bf4\u660e\u5185\u6838\u5e94\u5f53\u5982\u4f55\u5206\u914d\u5185\u5b58\u3002\u4e3b\u8981\u884c\u4e3a\u4fee\u9970\u7b26\u5982\u4e0b\uff1a<\/p>\n  Linux\u7684\u4e3b\u8981\u5185\u6838\u5185\u5b58\u5206\u914d\u884c\u4e3a\u4fee\u9970\u7b26  <\/p>\n\n\n\n\n\n\n\n\n\n\n\n
    \u4fee\u9970\u7b26<\/td>\n\u8bf4\u660e<\/td>\n<\/tr>\n
    __GFP_WAIT<\/td>\n\u5206\u914d\u5668\u53ef\u4ee5\u4f11\u7720<\/td>\n<\/tr>\n
    __GFP_HIGH<\/td>\n\u5206\u914d\u5668\u53ef\u4ee5\u8bbf\u95ee\u7d27\u6025\u4e8b\u4ef6\u7f13\u51b2\u6c60<\/td>\n<\/tr>\n
    __GFP_IO<\/td>\n\u5206\u914d\u5668\u53ef\u4ee5\u542f\u52a8\u78c1\u76d8IO<\/td>\n<\/tr>\n
    __GFP_FS<\/td>\n\u5206\u914d\u5668\u53ef\u4ee5\u542f\u52a8\u6587\u4ef6\u7cfb\u7edfIO<\/td>\n<\/tr>\n
    __GFP_COLD<\/td>\n\u5206\u914d\u5668\u5e94\u8be5\u4f7f\u7528\u9ad8\u901f\u7f13\u51b2\u4e2d\u5feb\u8981\u6dd8\u6c70\u7684\u9875\u6846<\/td>\n<\/tr>\n
    __GFP_NOWARN<\/td>\n\u5206\u914d\u5668\u4e0d\u53d1\u51fa\u8b66\u544a<\/td>\n<\/tr>\n
    __GFP_REPEAT<\/td>\n\u5206\u914d\u5931\u8d25\u65f6\u91cd\u65b0\u5206\u914d<\/td>\n<\/tr>\n
    __GFP_NOFAILT<\/td>\n\u5206\u914d\u5931\u8d25\u65f6\u91cd\u65b0\u5206\u914d\uff0c\u76f4\u81f3\u6210\u529f<\/td>\n<\/tr>\n
    __GFP_NORETRY<\/td>\n\u5206\u914d\u5931\u8d25\u65f6\u4e0d\u518d\u91cd\u65b0\u5206\u914d<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
    \u533a\u4fee\u9970\u7b26<\/strong><\/h4>\n
    \u533a\u4fee\u9970\u7b26\u8bf4\u660e\u9700\u8981\u4ece\u5185\u6838\u7a7a\u95f4\u7684\u54ea\u4e2a\u533a\u57df\u4e2d\u5206\u914d\u5185\u5b58\u3002\u5185\u5b58\u5206\u914d\u5668\u9ed8\u8ba4\u4ece\u5185\u6838\u7a7a\u95f4\u7684ZONE_NORMAL\u5f00\u59cb\u9010\u6e10\u5411\u9ad8\u7aef\u83b7\u53d6\u4e3a\u5185\u5b58\u8bf7\u6c42\u8005\u5206\u914d\u5185\u5b58\u533a\uff0c<\/strong>\u5982\u679c\u7528\u6237\u7279\u610f\u9700\u8981\u4eceZONE_DMA\u6216ZONE_HOGNMEM\u83b7\u5f97\u5185\u5b58\uff0c\u90a3\u4e48\u5c31\u9700\u8981\u5185\u5b58\u8bf7\u6c42\u8005\u5728\u5185\u5b58\u8bf7\u6c42\u51fd\u6570\u4e2d\u4f7f\u7528\u4ee5\u4e0b\u4e24\u4e2a\u533a\u4fee\u9970\u7b26\u8bf4\u660e\uff1a<\/p>\n  Linux\u7684\u4e3b\u8981\u5185\u6838\u5185\u5b58\u5206\u914d\u533a\u4fee\u9970\u7b26  <\/p>\n\n\n\n\n
    \u4fee\u9970\u7b26<\/td>\n\u8bf4\u660e<\/td>\n<\/tr>\n
    __GFP_DMA<\/td>\n\u4eceZONE_DMA\u533a\u5206\u914d\u5185\u5b58<\/td>\n<\/tr>\n
    __GFP_HIGHMEM<\/td>\n\u4eceZONE_HIGHMEM\u533a\u5206\u914d\u5185\u5b58<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
    \u7c7b\u578b\u4fee\u9970\u7b26<\/strong><\/h4>\n
    \u7c7b\u578b\u4fee\u9970\u7b26\u5b9e\u8d28\u4e0a\u662f\u4e0a\u8ff0\u6240\u8ff0\u4fee\u9970\u7b26\u7684\u8054\u5408\u5e94\u7528\u3002\u4e5f\u5c31\u662f\uff1a\u5c06\u4e0a\u8ff0\u7684\u67d0\u4e9b\u884c\u4e3a\u4fee\u9970\u7b26\u548c\u533a\u4fee\u9970\u7b26\uff0c\u7528\u201c|\u201d\u8fdb\u884c\u8fde\u63a5\u5e76\u53e6\u5916\u53d6\u540d\u7684\u4fee\u9970\u7b26\u3002\u8fd9\u91cc\u5c31\u4e0d\u591a\u4ecb\u7ecd\u4e86\u3002<\/p>\n
    \u5185\u6838\u5e38\u7528\u5185\u5b58\u5206\u914d\u53ca\u5730\u5740\u6620\u5c04\u51fd\u6570<\/strong><\/p>\n
    \u51fd\u6570vmalloc()<\/strong><\/h4>\n
    \u51fd\u6570vmalloc()\u5728vmalloc\u5206\u914d\u533a\u5206\u914d\u5185\u5b58\uff0c\u53ef\u83b7\u5f97\u865a\u62df\u5730\u5740\u8fde\u7eed\uff0c\u4f46\u5e76\u4e0d\u4fdd\u8bc1\u5176\u7269\u7406\u9875\u6846\u8fde\u7eed\u7684\u8f83\u5927\u5185\u5b58\u3002<\/strong>\u4e0e\u7269\u7406\u7a7a\u95f4\u7684\u5185\u5b58\u5206\u914d\u51fd\u6570malloc()\u6709\u6240\u533a\u522b\uff0cvmalloc()\u5206\u914d\u7684\u7269\u7406\u9875\u4e0d\u4f1a\u88ab\u4ea4\u6362\u51fa\u53bb\u3002\u51fd\u6570vmalloc()\u7684\u539f\u578b\u5982\u4e0b\uff1a<\/p>\n
    void *vmalloc(unsigned long size)\n{\n       return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL);\n}<\/pre>\n
    <\/p>\n
    void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot)\n{\n\treturn kmalloc(size, (gfp_mask | __GFP_COMP) & ~__GFP_HIGHMEM);\n}<\/pre>\n
    \u5176\u4e2d\uff0c\u53c2\u6570size\u4e3a\u6240\u8bf7\u6c42\u5185\u5b58\u7684\u5927\u5c0f\uff0c\u8fd4\u56de\u503c\u4e3a\u6240\u83b7\u5f97\u5185\u5b58\u865a\u62df\u5730\u5740\u6307\u9488\u3002<\/p>\n
    \u4e0evmalloc()\u914d\u5957\u7684\u91ca\u653e\u51fd\u6570\u5982\u4e0b\uff1a<\/p>\n
    void vfree(const void *addr)\n{\n\tkfree(addr);\n}<\/pre>\n
    \u5176\u4e2d\uff0c\u53c2\u6570addr\u4e3a\u5f85\u91ca\u653e\u5185\u5b58\u6307\u9488\u3002<\/p>\n
    \u51fd\u6570kmalloc()<\/strong><\/h4>\n
    kmalloc()\u662f\u5185\u6838\u53e6\u4e00\u4e2a\u5e38\u7528\u7684\u5185\u6838\u5206\u914d\u51fd\u6570\uff0c\u5b83\u53ef\u4ee5\u5206\u914d\u4e00\u6bb5\u672a\u6e05\u96f6\u7684\u8fde\u7eed\u7269\u7406\u5185\u5b58\u9875\uff0c\u8fd4\u56de\u503c\u4e3a\u76f4\u63a5\u6620\u5c04\u5730\u5740\u3002\u7531kmalloc()\u53ef\u5206\u914d\u7684\u5185\u5b58\u6700\u5927\u4e0d\u80fd\u8d85\u8fc732\u9875\u3002\u5176\u4f18\u70b9\u662f\u5206\u914d\u901f\u5ea6\u5feb\uff0c\u7f3a\u70b9\u662f\u4e0d\u80fd\u5206\u914d\u5927\u4e8e128KB\u7684\u5185\u5b58\u9875\uff08\u51fa\u4e8e\u8de8\u5e73\u53f0\u8003\u8651\uff09\u3002<\/strong><\/p>\n
    \u5728linux\/slab.h\u6587\u4ef6\u4e2d\uff0c\u8be5\u51fd\u6570\u7684\u539f\u578b\u58f0\u660e\u5982\u4e0b\uff1a<\/p>\n
    static __always_inline void *kmalloc(size_t size, gfp_t flags)\n{\n\tstruct kmem_cache *cachep;\n\tvoid *ret;\n\n\tif (__builtin_constant_p(size)) {\n\t\tint i = 0;\n\n\t\tif (!size)\n\t\t\treturn ZERO_SIZE_PTR;\n\n#define CACHE(x) \\\n\t\tif (size <= x) \\\n\t\t\tgoto found; \\\n\t\telse \\\n\t\t\ti++;\n#include <linux\/kmalloc_sizes.h>\n#undef CACHE\n\t\treturn NULL;\nfound:\n#ifdef CONFIG_ZONE_DMA\n\t\tif (flags & GFP_DMA)\n\t\t\tcachep = malloc_sizes[i].cs_dmacachep;\n\t\telse\n#endif\n\t\t\tcachep = malloc_sizes[i].cs_cachep;\n\n\t\tret = kmem_cache_alloc_notrace(cachep, flags);\n\n\t\ttrace_kmalloc(_THIS_IP_, ret,\n\t\t\t      size, slab_buffer_size(cachep), flags);\n\n\t\treturn ret;\n\t}\n\treturn __kmalloc(size, flags);\n}<\/pre>\n
    \u5176\u4e2d\uff0c\u53c2\u6570size\u4e3a\u4ee5\u5b57\u8282\u4e3a\u5355\u4f4d\u8868\u793a\u7684\u6240\u7533\u8bf7\u7a7a\u95f4\u7684\u5927\u5c0f\uff1b\u53c2\u6570flags\u51b3\u5b9a\u4e86\u6240\u5206\u914d\u7684\u5185\u5b58\u9002\u5408\u4ec0\u4e48\u573a\u5408\u3002<\/p>\n
    \u4e0e\u51fd\u6570kmalloc()\u5bf9\u5e94\u7684\u91ca\u653e\u51fd\u6570\u5982\u4e0b\uff1a<\/p>\n
    void kfree(const void *objp)\n{\n\tstruct kmem_cache *c;\n\tunsigned long flags;\n\n\ttrace_kfree(_RET_IP_, objp);\n\n\tif (unlikely(ZERO_OR_NULL_PTR(objp)))\n\t\treturn;\n\tlocal_irq_save(flags);\n\tkfree_debugcheck(objp);\n\tc = virt_to_cache(objp);\n\tdebug_check_no_locks_freed(objp, obj_size(c));\n\tdebug_check_no_obj_freed(objp, obj_size(c));\n\t__cache_free(c, (void *)objp);\n\tlocal_irq_restore(flags);\n}<\/pre>\n
    \u5c0f\u7ed3\u4e00\u4e0b\uff0ckmalloc\u3001vmalloc\u3001malloc\u7684\u533a\u522b\uff1a<\/p>\n
      \n
    • \n
      kmalloc\u548cvmalloc\u662f\u5206\u914d\u7684\u662f\u5185\u6838\u7684\u5185\u5b58\uff0cmalloc\u5206\u914d\u7684\u662f\u7528\u6237\u7684\u5185\u5b58\uff1b<\/strong><\/p>\n<\/li>\n
    • \n
      kmalloc\u4fdd\u8bc1\u5206\u914d\u7684\u5185\u5b58\u5728\u7269\u7406\u4e0a\u662f\u8fde\u7eed\u7684\uff0cvmalloc\u4fdd\u8bc1\u7684\u662f\u5728\u865a\u62df\u5730\u5740\u7a7a\u95f4\u4e0a\u7684\u8fde\u7eed\uff0cmalloc\u4e0d\u4fdd\u8bc1\u4efb\u4f55\u4e1c\u897f\uff1b<\/strong><\/p>\n<\/li>\n
    • \n
      kmalloc\u80fd\u5206\u914d\u7684\u5927\u5c0f\u6709\u9650\uff0cvmalloc\u548cmalloc\u80fd\u5206\u914d\u7684\u5927\u5c0f\u76f8\u5bf9\u8f83\u5927\uff1b<\/strong><\/p>\n<\/li>\n
    • \n
      vmalloc\u6bd4kmalloc\u8981\u6162\u3002<\/strong><\/p>\n<\/li>\n<\/ul>\n
      \u4e5f\u5c31\u662f\u8bf4\uff1akmalloc\u3001vmalloc\u8fd9\u4e24\u4e2a\u51fd\u6570\u6240\u5206\u914d\u7684\u5185\u5b58\u90fd\u5904\u4e8e\u5185\u6838\u7a7a\u95f4\uff0c\u5373\u4ece3GB\uff5e4GB\uff1b\u4f46\u4f4d\u7f6e\u4e0d\u540c\uff0ckmalloc()\u5206\u914d\u7684\u5185\u5b58\u5904\u4e8e3GB\uff5ehigh_memory\uff08ZONE_DMA\u3001ZONE_NORMAL\uff09\u4e4b\u95f4\uff0c\u800cvmalloc()\u5206\u914d\u7684\u5185\u5b58\u5728VMALLOC_START\uff5e4GB\uff08ZONE_HIGHMEM\uff09\u4e4b\u95f4\uff0c\u4e5f\u5c31\u662f\u975e\u8fde\u7eed\u5185\u5b58\u533a\u3002\u4e00\u822c\u60c5\u51b5\u4e0b\u5728\u9a71\u52a8\u7a0b\u5e8f\u4e2d\u90fd\u662f\u8c03\u7528kmalloc()\u6765\u7ed9\u6570\u636e\u7ed3\u6784\u5206\u914d\u5185\u5b58\uff0c\u800cvmalloc()\u7528\u5728\u4e3a\u6d3b\u52a8\u7684\u4ea4\u6362\u533a\u5206\u914d\u6570\u636e\u7ed3\u6784\uff0c\u4e3a\u67d0\u4e9bI\/O\u9a71\u52a8\u7a0b\u5e8f\u5206\u914d\u7f13\u51b2\u533a\uff0c\u6216\u4e3a\u6a21\u5757\u5206\u914d\u7a7a\u95f4\u3002<\/strong><\/p>\n
      \"linux\u9a71\u52a8\u7a0b\u5e8f\u8fd0\u884c\u7a7a\u95f4\u662f\u4ec0\u4e48\u63d2\u56fe7\"<\/p>\n
      \u51fd\u6570alloc_pages()<\/strong><\/h4>\n
      \u4e0e\u4e0a\u8ff0\u5728\u865a\u62df\u7a7a\u95f4\u5206\u914d\u5185\u5b58\u7684\u51fd\u6570\u4e0d\u540c\uff0calloc_pages()\u662f\u5728\u7269\u7406\u5185\u5b58\u7a7a\u95f4\u5206\u914d\u7269\u7406\u9875\u6846\u7684\u51fd\u6570<\/strong>\uff0c\u5176\u539f\u578b\u5982\u4e0b\uff1a<\/p>\n
      static inline struct page * alloc_pages(gfp_t gfp_mask, unsigned int order)\n{\n\tif (unlikely(order >= MAX_ORDER))\n\t\treturn NULL;\n\n\treturn alloc_pages_current(gfp_mask, order);\n}<\/pre>\n
      \u5176\u4e2d\uff0c\u53c2\u6570order\u8868\u793a\u6240\u5206\u914d\u9875\u6846\u7684\u6570\u76ee\uff0c\u8be5\u6570\u76ee\u4e3a2^order\u3002order\u7684\u6700\u5927\u503c\u7531include\/Linux\/Mmzone.h\u6587\u4ef6\u4e2d\u7684\u5b8fMAX_ORDER\u51b3\u5b9a\u3002\u53c2\u6570gfp_mask\u4e3a\u8bf4\u660e\u5185\u5b58\u9875\u6846\u5206\u914d\u65b9\u5f0f\u53ca\u4f7f\u7528\u573a\u5408\u3002<\/p>\n
      <\/code> <\/p>\n
      \u51fd\u6570\u8fd4\u56de\u503c\u4e3a\u9875\u6846\u5757\u7684\u7b2c\u4e00\u4e2a\u9875\u6846page\u7ed3\u6784\u7684\u5730\u5740\u3002<\/p>\n
      \u8c03\u7528\u4e0b\u5217\u51fd\u6570\u53ef\u4ee5\u83b7\u5f97\u9875\u6846\u7684\u865a\u62df\u5730\u5740\uff1a<\/p>\n
      <\/code><\/p>\n
      void *page_address(struct page *page)\n{\n\tunsigned long flags;\n\tvoid *ret;\n\tstruct page_address_slot *pas;\n \n\tif (!PageHighMem(page))\n\t\treturn lowmem_page_address(page);\n \n\tpas = page_slot(page);\n\tret = NULL;\n\tspin_lock_irqsave(&pas->lock, flags);\n\tif (!list_empty(&pas->lh)) {\n\t\tstruct page_address_map *pam;\n \n\t\tlist_for_each_entry(pam, &pas->lh, list) {\n\t\t\tif (pam->page == page) {\n\t\t\t\tret = pam->virtual;\n\t\t\t\tgoto done;\n\t\t\t}\n\t\t}\n\t}\ndone:\n\tspin_unlock_irqrestore(&pas->lock, flags);\n\treturn ret;\n}<\/code><\/pre>\n
      \u4f7f\u7528\u51fd\u6570alloc_pages()\u83b7\u5f97\u7684\u5185\u5b58\u5e94\u8be5\u4f7f\u7528\u4e0b\u9762\u7684\u51fd\u6570\u91ca\u653e\uff1a<\/code><\/p>\n
      void __free_pages(struct page *page, unsigned int order)\n{\n\tif (put_page_testzero(page)) {\n\t\tif (order == 0)\n\t\t\tfree_hot_page(page);\n\t\telse\n\t\t\t__free_pages_ok(page, order);\n\t}\n}<\/code><\/pre>\n
      \u51fd\u6570kmap()<\/strong><\/code><\/p>\n<\/p>\n
      kmap()\u662f\u4e00\u4e2a\u6620\u5c04\u51fd\u6570\uff0c\u5b83\u53ef\u4ee5\u5c06\u4e00\u4e2a\u7269\u7406\u9875\u6846\u6620\u5c04\u5230\u5185\u6838\u7a7a\u95f4\u7684\u53ef\u6301\u4e45\u6620\u5c04\u533a\u3002\u8fd9\u79cd\u6620\u5c04\u7c7b\u4f3c\u4e8e\u5185\u6838ZONE_NORMAL\u7684\u56fa\u5b9a\u6620\u5c04\uff0c\u4f46\u865a\u62df\u5730\u5740\u4e0e\u7269\u7406\u5730\u5740\u7684\u504f\u79fb\u4e0d\u4e00\u5b9a\u662fPAGE_OFFSET\u3002\u7531\u4e8e\u5185\u6838\u53ef\u6301\u4e45\u6620\u5c04\u533a\u7684\u5bb9\u91cf\u6709\u9650\uff08\u603b\u5171\u53ea\u67094MB\uff09\uff0c\u56e0\u6b64\u5f53\u5185\u5b58\u4f7f\u7528\u5b8c\u6bd5\u540e\uff0c\u5e94\u8be5\u7acb\u5373\u91ca\u653e\u3002<\/strong><\/p>\n
      \u51fd\u6570kmap()\u7684\u51fd\u6570\u539f\u578b\u5982\u4e0b\uff1a<\/p>\n
      <\/code><\/p>\n
      void *kmap(struct page *page)\n{\n\tmight_sleep();\n\tif (!PageHighMem(page))\n\t\treturn page_address(page);\n\treturn kmap_high(page);\n}<\/code><\/pre>\n
      \u5c0f\u7ed3<\/strong><\/code><\/p>\n
      \u7531\u4e8eCPU\u7684\u5730\u5740\u603b\u7ebf\u53ea\u670932\u4f4d\uff0c 32\u7684\u5730\u5740\u603b\u7ebf\u65e0\u8bba\u662f\u4ece\u903b\u8f91\u4e0a\u8fd8\u662f\u4ece\u7269\u7406\u4e0a\u90fd\u53ea\u80fd\u63cf\u8ff04G\u7684\u5730\u5740\u7a7a\u95f4\uff08232=4Gbit\uff09\uff0c\u5728\u7269\u7406\u4e0a\u7406\u8bba\u4e0a\u6700\u591a\u62e5\u67094G\u5185\u5b58\uff08\u9664\u4e86IO\u5730\u5740\u7a7a\u95f4\uff0c\u5b9e\u9645\u5185\u5b58\u5bb9\u91cf\u5c0f\u4e8e4G\uff09\uff0c\u903b\u8f91\u7a7a\u95f4\u4e5f\u53ea\u80fd\u63cf\u8ff04G\u7684\u7ebf\u6027\u5730\u5740\u7a7a\u95f4\u3002<\/code><\/p>\n
      \u4e3a\u4e86\u5408\u7406\u7684\u5229\u7528\u903b\u8f914G\u7a7a\u95f4\uff0cLinux\u91c7\u7528\u4e863\uff1a1\u7684\u7b56\u7565\uff0c\u5373\u5185\u6838\u5360\u75281G\u7684\u7ebf\u6027\u5730\u5740\u7a7a\u95f4\uff0c\u7528\u6237\u5360\u75283G\u7684\u7ebf\u6027\u5730\u5740\u7a7a\u95f4\u3002\u6240\u4ee5\u7528\u6237\u8fdb\u7a0b\u7684\u5730\u5740\u8303\u56f4\u4ece0~3G\uff0c\u5185\u6838\u5730\u5740\u8303\u56f4\u4ece3G~4G\uff0c\u4e5f\u5c31\u662f\u8bf4\uff0c\u5185\u6838\u7a7a\u95f4\u53ea\u67091G\u7684\u903b\u8f91\u7ebf\u6027\u5730\u5740\u7a7a\u95f4\u3002<\/code><\/p>\n
      \u5982\u679cLinux\u7269\u7406\u5185\u5b58\u5c0f\u4e8e1G\u7684\u7a7a\u95f4\uff0c\u901a\u5e38\u5185\u6838\u628a\u7269\u7406\u5185\u5b58\u4e0e\u5176\u5730\u5740\u7a7a\u95f4\u505a\u4e86\u7ebf\u6027\u6620\u5c04\uff0c\u4e5f\u5c31\u662f\u4e00\u4e00\u6620\u5c04\uff0c\u8fd9\u6837\u53ef\u4ee5\u63d0\u9ad8\u8bbf\u95ee\u901f\u5ea6\u3002\u4f46\u662f\uff0c\u5f53Linux\u7269\u7406\u5185\u5b58\u8d85\u8fc71G\u65f6\uff0c\u7ebf\u6027\u8bbf\u95ee\u673a\u5236\u5c31\u4e0d\u591f\u7528\u4e86\uff0c\u56e0\u4e3a\u53ea\u80fd\u67091G\u7684\u5185\u5b58\u53ef\u4ee5\u88ab\u6620\u5c04\uff0c\u5269\u4f59\u7684\u7269\u7406\u5185\u5b58\u65e0\u6cd5\u88ab\u5185\u6838\u7ba1\u7406\uff0c\u6240\u4ee5\uff0c\u4e3a\u4e86\u89e3\u51b3\u8fd9\u4e00\u95ee\u9898\uff0cLinux\u628a\u5185\u6838\u5730\u5740\u5206\u4e3a\u7ebf\u6027\u533a\u548c\u975e\u7ebf\u6027\u533a\u4e24\u90e8\u5206\uff0c\u7ebf\u6027\u533a\u89c4\u5b9a\u6700\u5927\u4e3a896M\uff0c\u5269\u4e0b\u7684128M\u4e3a\u975e\u7ebf\u6027\u533a\u3002\u4ece\u800c\uff0c\u7ebf\u6027\u533a\u6620\u5c04\u7684\u7269\u7406\u5185\u5b58\u6210\u4e3a\u4f4e\u7aef\u5185\u5b58\uff0c\u5269\u4e0b\u7684\u7269\u7406\u5185\u5b58\u88ab\u6210\u4e3a\u9ad8\u7aef\u5185\u5b58\u3002\u4e0e\u7ebf\u6027\u533a\u4e0d\u540c\uff0c\u975e\u7ebf\u6027\u533a\u4e0d\u4f1a\u63d0\u524d\u8fdb\u884c\u5185\u5b58\u6620\u5c04\uff0c\u800c\u662f\u5728\u4f7f\u7528\u65f6\u52a8\u6001\u6620\u5c04\u3002<\/strong><\/code><\/p>\n
      \u4f4e\u7aef\u5185\u5b58\u53c8\u5206\u6210\u4e24\u90e8\u5206\uff1aZONE_DMA\uff1a\u5185\u6838\u7a7a\u95f4\u5f00\u59cb\u768416MB\u3001ZONE_NORMAL\uff1a\u5185\u6838\u7a7a\u95f416MB~896MB\uff08\u56fa\u5b9a\u6620\u5c04\uff09\u3002\u5269\u4e0b\u7684\u5c31\u662f\u9ad8\u7aef\u5185\u5b58\uff1aZONE_HIGHMEM \uff1a\u5185\u6838\u7a7a\u95f4896MB ~ \u7ed3\u675f\uff081G\uff09\u3002<\/strong><\/code><\/p>\n
      \u6839\u636e\u5e94\u7528\u76ee\u6807\u4e0d\u540c\uff0c\u9ad8\u7aef\u5185\u5b58\u533a\u5206vmalloc\u533a\u3001\u53ef\u6301\u4e45\u6620\u5c04\u533a\u548c\u4e34\u65f6\u6620\u5c04\u533a\u4e09\u90e8\u5206\u3002vmalloc\u533a\u4f7f\u7528vmalloc()\u51fd\u6570\u8fdb\u884c\u5206\u914d\uff1b\u53ef\u6301\u4e45\u6620\u5c04\u533a\u4f7f\u7528allc_pages()\u83b7\u5f97\u5bf9\u5e94\u7684 page\uff0c\u5728\u5229\u7528kmap()\u51fd\u6570\u76f4\u63a5\u6620\u5c04\uff1b\u4e34\u65f6\u6620\u5c04\u533a\u4e00\u822c\u7528\u4e8e\u7279\u6b8a\u9700\u6c42\u3002<\/strong><\/code><\/p>\n  \u7528\u6237\u7a7a\u95f4\u548c\u5185\u6838\u7a7a\u95f4  <\/p>\n\n\n\n\n\n\n\n
      \u5185\u6838\u7a7a\u95f4\uff083G~4G\uff09<\/td>\n\n
      \u9ad8\u7aef\u5185\u5b58\uff083G+high_memory~4G\uff09ZONE_HIGHMEM<\/p>\n
      \u975e\u7ebf\u6027\u6620\u5c04\u533a<\/p>\n<\/td>\n
      		\u4e34\u65f6\u6620\u5c04\u533a<\/td>\n<\/tr>\n
      \u53ef\u6301\u4e45\u6620\u5c04\u533a<\/td>\n<\/tr>\n
      vmalloc\u533a<\/td>\n<\/tr>\n
      \n
      \u4f4e\u7aef\u5185\u5b58\uff083G~3G+high_memory-1\uff09<\/p>\n
      \u7ebf\u6027\u6620\u5c04\u533a\uff08\u56fa\u5b9a\u6620\u5c04\u533a\uff09<\/p>\n<\/td>\n
      		ZONE_NORMAL<\/td>\n<\/tr>\n
      ZONE_DMA<\/td>\n<\/tr>\n
      \u7528\u6237\u7a7a\u95f4\uff080~3G-1\uff09<\/td>\n\u9875\u76ee\u5f55–>\u4e2d\u95f4\u9875\u76ee\u5f55–>\u9875\u8868<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
      \u4eca\u5929\u5e26\u5927\u5bb6\u4e86\u89e3\u4e86\u7684\u76f8\u5173\u77e5\u8bc6\uff0c\u5e0c\u671b\u5bf9\u4f60\u6709\u6240\u5e2e\u52a9\uff1b\u5173\u4e8e\u6587\u7ae0\u7684\u6280\u672f\u77e5\u8bc6\u6211\u4eec\u4f1a\u4e00\u70b9\u70b9\u6df1\u5165\u4ecb\u7ecd\uff0c\u6b22\u8fce\u5927\u5bb6\u5173\u6ce8\u7c73\u4e91\u516c\u4f17\u53f7\uff0c\u4e00\u8d77\u5b66\u4e60\u7f16\u7a0b~<\/code><\/p><\/p>\n","protected":false},"excerpt":{"rendered":"
      linux\u9a71\u52a8\u7a0b\u5e8f\u8fd0\u884c\u7a7a\u95f4\u662f\u4ec0\u4e48 \u6587\u7ae0\u5c0f\u767d\u4e00\u679a\uff0c\u6b63\u5728\u4e0d\u65ad\u5b66\u4e60\u79ef\u7d2f\u77e5\u8bc6\uff0c\u73b0\u5c06\u5b66\u4e60\u5230\u7684\u77e5\u8bc6\u8bb0\u5f55\u4e00\u4e0b\uff0c\u4e5f\u662f\u5c06\u6211\u7684\u6240\u5f97\u5206\u4eab\u7ed9\u5927\u5bb6\uff01\u800c\u4eca\u5929\u8fd9\u7bc7\u6587\u7ae0\u300alinux\u9a71\u52a8\u7a0b\u5e8f\u8fd0\u884c\u7a7a\u95f4\u662f\u4ec0\u4e48\u300b\u5e26\u5927\u5bb6\u6765\u4e86\u89e3\u4e00\u4e0b##content_title##\uff0c\u5e0c\u671b\u5bf9\u5927\u5bb6\u7684\u77e5\u8bc6\u79ef\u7d2f\u6709\u6240\u5e2e\u52a9\uff0c\u4ece\u800c\u5f25\u8865\u81ea\u5df1\u7684\u4e0d\u8db3\uff0c\u52a9\u529b\u5b9e\u6218\u5f00\u53d1\uff01 linux\u9a71\u52a8\u7a0b\u5e8f\u8fd0\u884c\u5728\u201c\u5185\u6838\u201d\u7a7a\u95f4\u3002\u4e00\u822c\u60c5\u51b5\u4e0b\u9a71\u52a8\u7a0b\u5e8f\u4e2d\u90fd\u662f\u8c03\u7528kmalloc()\u6765\u7ed9\u6570\u636e\u7ed3\u6784\u5206\u914d\u5185\u5b58\uff0c\u8c03\u7528vmalloc()\u4e3a\u6d3b\u52a8\u7684\u4ea4\u6362\u533a\u5206\u914d\u6570\u636e\u7ed3\u6784\uff0c\u4e3a\u67d0\u4e9bI\/O\u9a71\u52a8\u7a0b\u5e8f\u5206\u914d\u7f13\u51b2\u533a\uff0c\u6216\u4e3a\u6a21\u5757\u5206\u914d\u7a7a\u95f4\uff1bkmalloc\u548cvmalloc\u5206\u914d\u7684\u662f\u5185\u6838\u7684\u5185\u5b58\u3002 linux\u9a71\u52a8\u7a0b\u5e8f\u8fd0\u884c\u5728\u201c\u5185\u6838\u201d\u7a7a\u95f4\u3002 \u5bf9\u4e8e\u4e00\u822c\u7f16\u5199\u7684\u5355\u7247\u673a\u7a0b\u5e8f\u6765\u8bf4\u5e94\u7528\u7a0b\u5e8f\u548c\u9a71\u52a8\u7a0b\u5e8f\u5f80\u5f80\u662f\u6742\u7cc5\u7684\uff0c\u62e5\u6709\u4e00\u5b9a\u80fd\u529b\u6c34\u5e73\u7684\u5355\u7247\u673a\u7a0b\u5e8f\u7f16\u7a0b\u4eba\u5458\u53ef\u4ee5\u5b9e\u73b0\u5e94\u7528\u548c\u9a71\u52a8\u7684\u5206\u5c42\u3002\u800c\u5728Linux\u7cfb\u7edf\u4e2d\u5df2\u7ecf\u5f3a\u5236\u5c06\u5e94\u7528\u548c\u9a71\u52a8\u8fdb\u884c\u4e86\u5206\u5c42\u3002 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\u5e94\u7528\u7a0b\u5e8f\u8fd0\u884c\u5728\u7528\u6237\u7a7a\u95f4\uff0c\u9a71\u52a8\u7a0b\u5e8f\u8fd0\u884c\u5728\u5185\u6838\u7a7a\u95f4\u3002\u5904\u4e8e\u7528\u6237\u7a7a\u95f4\u5e94\u7528\u7a0b\u5e8f\u5982\u679c\u60f3\u8981\u5b9e\u73b0\u5bf9\u5185\u6838\u7684\u64cd\u4f5c\uff0c\u5fc5\u987b\u7ecf\u8fc7\u4e00\u79cd”\u7cfb\u7edf\u8c03\u7528”\u7684\u65b9\u6cd5\uff0c\u5b9e\u73b0\u4ece\u7528\u6237\u7a7a\u95f4\u8fdb\u5165\u5185\u6838\u7a7a\u95f4\uff0c\u5b9e\u73b0\u5bf9\u5e95\u5c42\u7684\u64cd\u4f5c\u3002 Linux\u4e2d\u7684\u5185\u6838\u7a7a\u95f4 \u5185\u6838\u4e5f\u662f\u7a0b\u5e8f\uff0c\u4e5f\u5e94\u8be5\u5177\u6709\u81ea\u5df1\u7684\u865a\u5b58\u7a7a\u95f4\uff0c\u4f46\u662f\u4f5c\u4e3a\u4e00\u79cd\u4e3a\u7528\u6237\u7a0b\u5e8f\u670d\u52a1\u7684\u7a0b\u5e8f\uff0c\u5185\u6838\u7a7a\u95f4\u6709\u5b83\u81ea\u5df1\u7684\u7279\u70b9\u3002 \u5185\u6838\u7a7a\u95f4\u4e0e\u7528\u6237\u7a7a\u95f4\u7684\u5173\u7cfb 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\u4f8b\u5982\uff1a\u5728i386\u8fd9\u79cd32\u4f4d\u7684\u786c\u4ef6\u5e73\u53f0\u4e0a\uff0cLinux\u5728\u6587\u4ef6page.h\u4e2d\u5b9a\u4e49\u4e86\u4e00\u4e2a\u5e38\u91cfPAGE_OFFSET\uff1a #ifdef CONFIG_MMU #define __PAGE_OFFSET  (0xC0000000)        \/\/0xC0000000\u4e3a3GB #else #define __PAGE_OFFSET  (0x00000000) #endif #define PAGE_OFFSET ((unsigned long)__PAGE_OFFSET) Linux\u4ee5PAGE_OFFSET\u4e3a\u754c\u5c064GB\u7684\u865a\u62df\u5185\u5b58\u7a7a\u95f4\u5206\u6210\u4e86\u4e24\u90e8\u5206\uff1a\u5730\u57400~3G-1\u8fd9\u6bb5\u4f4e\u5730\u5740\u7a7a\u95f4\u4e3a\u7528\u6237\u7a7a\u95f4\uff0c\u5927\u5c0f\u4e3a3GB\uff1b\u5730\u57403GB~4GB-1\u8fd9\u6bb5\u9ad8\u5730\u5740\u7a7a\u95f4\u4e3a\u5185\u6838\u7a7a\u95f4\uff0c\u5927\u5c0f\u4e3a1GB\u3002 \u5f53\u7cfb\u7edf\u4e2d\u8fd0\u884c\u591a\u4e2a\u7a0b\u5e8f\u65f6\uff0c\u591a\u4e2a\u7528\u6237\u7a7a\u95f4\u4e0e\u5185\u6838\u7a7a\u95f4\u7684\u5173\u7cfb\u53ef\u4ee5\u8868\u793a\u5982\u4e0b\u56fe\uff1a 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