目录
前言检查托管内存使用p collect -p 4807Writing minidump with heap to ./core_20190430_185145Complete分析 core dump
接下来可以使用 dotnet-dump analyze 对已生成的dump文件进行分析。
dotnet-dump analyze core_20190430_185145
这里的 core_20190430_185145 就是你想要分析的dump名，值得一提的是：如果你遇到了 libdl.so cannot be found 错误，建议以安装一下 libc6-dev package 包。
首先我们通过 sos 命令查看 托管堆 上的所有对象统计清单。
> dumpheap -statStatistics: MT Count TotalSize Class Name...00007f6c1eeefba8 576 59904 System.Reflection.RuntimeMethodInfo00007f6c1dc021c8 1749 95696 System.SByte[]00000000008c9db0 3847 116080 Free00007f6c1e784a18 175 128640 System.Char[]00007f6c1dbf5510 217 133504 System.Object[]00007f6c1dc014c0 467 416464 System.Byte[]00007f6c21625038 6 4063376 testwebapi.Controllers.Customer[]00007f6c20a67498 200000 4800000 testwebapi.Controllers.Customer00007f6c1dc00f90 206770 19494060 System.StringTotal 428516 objects
从输出看，大头都是些 String 和 Customer 对象,然后可以通过 mt 参数来获取该方法表下所有的实例对象。
> dumpheap -mt 00007faddaa50f90 Address MT Size...00007f6ad09421f8 00007faddaa50f90 94...00007f6ad0965b20 00007f6c1dc00f90 8000007f6ad0965c10 00007f6c1dc00f90 8000007f6ad0965d00 00007f6c1dc00f90 http://www.easck.com 8000007f6ad0965df0 00007f6c1dc00f90 8000007f6ad0965ee0 00007f6c1dc00f90 80Statistics: MT Count TotalSize Class Name00007f6c1dc00f90 206770 19494060 System.StringTotal 206770 objects
接下来可以用 !gcroot 查看某一个string到底被谁持有着？
> gcroot -all 00007f6ad09421f8Thread 3f68: 00007F6795BB58A0 00007F6C1D7D0745 System.Diagnostics.Tracing.CounterGroup.PollForValues() [/_/src/System.Private.CoreLib/shared/System/Diagnostics/Tracing/CounterGroup.cs @ 260] rbx: (interior) -> 00007F6BDFFFF038 System.Object[] -> 00007F69D0033570 testwebapi.Controllers.Processor -> 00007F69D0033588 testwebapi.Controllers.CustomerCache -> 00007F69D00335A0 System.Collections.Generic.List`1[[testwebapi.Controllers.Customer, DiagnosticScenarios]] -> 00007F6C000148A0 testwebapi.Controllers.Customer[] -> 00007F6AD0942258 testwebapi.Controllers.Customer -> 00007F6AD09421F8 System.StringHandleTable: 00007F6C98BB15F8 (pinned handle) qckIEZRP -> 00007F6BDFFFF038 System.Object[] -> 00007F69D0033570 testwebapi.Controllers.Processor -> 00007F69D0033588 testwebapi.Controllers.CustomerCache -> 00007F69D00335A0 System.Collections.Generic.List`1[[testwebapi.Controllers.Customer, DiagnosticScenarios]] -> 00007F6C000148A0 testwebapi.Controllers.Customer[] -> 00007F6AD0942258 testwebapi.Controllers.Customer -> 00007F6AD09421F8 System.StringFound 2 roots.
从string的引用链看，它是被 CustomerCache 所持有，然后就可以到代码中寻找问题啦。
原文链接：https://docs.microsoft.com/en-us/dotnet/core/diagnostics/debug-memory-leak
