专业的建设网站服务,手机app怎么开发的,网站建设与管理好处,网站建设项目管理基本要求一#xff1a;背景 1. 讲故事上个月中旬#xff0c;星球里的一位朋友在微信找我#xff0c;说他的程序跑着跑着内存会不断的缓慢增长并无法释放#xff0c;寻求如何解决 #xff1f;得#xff0c;看样子星球还得好好弄#xff01;#xff01;#xff01;#x1f602;… 一背景 1. 讲故事上个月中旬星球里的一位朋友在微信找我说他的程序跑着跑着内存会不断的缓慢增长并无法释放寻求如何解决 得看样子星球还得好好弄 不管怎么说先上 windbg 说话。二Windbg 分析 1. 经验推理从朋友的截图看有大量的 8216 字节的 byte[]这表示什么呢追随本系列的朋友应该知道有一篇 某三甲医院 的内存暴涨的dump中也同样有此 size (8216-248192) 的 byte[] 数组 他的问题是 Oracle 中读取某大字段时sdk里的 OraBuf 出了问题换句话说这肯定又是底层或者第三方库中的池对象搞出来的东西接下来从 托管堆 看起。2. 查看托管堆0:000 !dumpheap -stat
Statistics:
00007ffe107248f0 483707 15478624 System.Threading.PreAllocatedOverlapped
00007ffe1079c160 483744 15479808 System.Threading.ThreadPoolBoundHandle
00007ffe1079cff8 483701 23217648 System.Threading._IOCompletionCallback
00007ffe106e7a90 483704 23217792 Microsoft.Win32.SafeHandles.SafeFileHandle
00007ffe1079b088 483703 30956992 System.IO.FileSystemWatcherAsyncReadState
00007ffe1079ceb0 483707 34826904 System.Threading.OverlappedData
00007ffe1079ccb0 483707 34826904 System.Threading.ThreadPoolBoundHandleOverlapped
0000016c64651080 245652 1473128080 Free
00007ffe105abf30 488172 3977571092 System.Byte[]扫完托管堆卧槽 byte[] 没吸引到我反而被 System.IO.FileSystemWatcherAsyncReadState 吸引到了毕竟被 System.IO.FileSystemWatcher 折腾多次了它已经深深打入了我的脑海。。。毕竟让程序卡死让句柄爆高的都是它。。。这一回八成又是它惹的祸看样子还是有很多程序员栽在这里哈。为做到严谨我还是从最大的 System.Byte[] 入手按size对它进行分组再按totalsize降序丑陋的脚本我就不发了直接上脚本的输出结果。!dumpheap -mt 00007ffe105abf30
size8216,count483703,totalsize3790M
size8232,count302,totalsize2M
size65560,count6,totalsize0M
size131096,count2,totalsize0M
size4120,count11,totalsize0M
size56,count301,totalsize0M
size88,count186,totalsize0M
size848,count16,totalsize0M
size152,count85,totalsize0M
size46,count242,totalsize0M
size279,count38,totalsize0M!dumpheap -mt 00007ffe105abf30 -min 0n8216 -max 0n8216 -short0000016c664277f0
0000016c66432a48
0000016c6648ef88
0000016c6649daa8
0000016c6649fb00
0000016c664a8b90
...从输出结果看size8216 的 byte[] 有 48w 个然后脚本也列出了一些 8216 大小的 address 地址接下来用 !gcroot 看下这些地址的引用。0:000 !gcroot 0000016c664277f0
HandleTable:0000016C65FC28C0 (async pinned handle)- 0000016C6628DEB0 System.Threading.OverlappedData- 0000016C664277F0 System.Byte[]Found 1 unique roots (run !gcroot -all to see all roots).
0:000 !gcroot 0000016c667c80d0
HandleTable:0000016C65FB7920 (async pinned handle)- 0000016C663260F8 System.Threading.OverlappedData- 0000016C667C80D0 System.Byte[]从输出中可以看到这些 byte[] 都是 async pinned也就是当异步IO回来的时候需要给 byte[] 填充的存储空间接下来我们看看如何通过 OverlappedData 找到源码中定义为 8192 大小的 byte[] 地方。如果你了解 FileSystemWatcher 反向查找链大概是这样的 OverlappedData - ThreadPoolBoundHandleOverlapped - System.IO.FileSystemWatcherAsyncReadState - Buffer[] 这中间涉及到 ThreadPool 和 SafeHandle 的绑定。0:000 !do 0000016C663260F8
Name: System.Threading.OverlappedData
MethodTable: 00007ffe1079ceb0
EEClass: 00007ffe107ac8d0
Size: 72(0x48) bytes
File: C:\Program Files\dotnet\shared\Microsoft.NETCore.App\5.0.10\System.Private.CoreLib.dll
Fields:MT Field Offset Type VT Attr Value Name
00007ffe106e3c08 40009ce 8 System.IAsyncResult 0 instance 0000000000000000 _asyncResult
00007ffe104a0c68 40009cf 10 System.Object 0 instance 0000016c66326140 _callback
00007ffe1079cb60 40009d0 18 ...eading.Overlapped 0 instance 0000016c663260b0 _overlapped
00007ffe104a0c68 40009d1 20 System.Object 0 instance 0000016c667c80d0 _userObject
00007ffe104af508 40009d2 28 PTR 0 instance 00000171728f66e0 _pNativeOverlapped
00007ffe104aee60 40009d3 30 System.IntPtr 1 instance 0000000000000000 _eventHandle
00007ffe104ab258 40009d4 38 System.Int32 1 instance 0 _offsetLow
00007ffe104ab258 40009d5 3c System.Int32 1 instance 0 _offsetHigh
0:000 !do 0000016c663260b0
Name: System.Threading.ThreadPoolBoundHandleOverlapped
MethodTable: 00007ffe1079ccb0
EEClass: 00007ffe107ac858
Size: 72(0x48) bytes
File: C:\Program Files\dotnet\shared\Microsoft.NETCore.App\5.0.10\System.Private.CoreLib.dll
Fields:MT Field Offset Type VT Attr Value Name
00007ffe1079ceb0 40009d6 8 ...ng.OverlappedData 0 instance 0000016c663260f8 _overlappedData
00007ffe1079b818 40009c0 10 ...ompletionCallback 0 instance 0000016f661ab8a0 _userCallback
00007ffe104a0c68 40009c1 18 System.Object 0 instance 0000016c667ca0e8 _userState
00007ffe107248f0 40009c2 20 ...locatedOverlapped 0 instance 0000016c66326090 _preAllocated
00007ffe104af508 40009c3 30 PTR 0 instance 00000171728f66e0 _nativeOverlapped
00007ffe1079c160 40009c4 28 ...adPoolBoundHandle 0 instance 0000000000000000 _boundHandle
00007ffe104a7238 40009c5 38 System.Boolean 1 instance 0 _completed
00007ffe1079b818 40009bf 738 ...ompletionCallback 0 static 0000016f661ab990 s_completionCallback
0:000 !do 0000016c667ca0e8
Name: System.IO.FileSystemWatcherAsyncReadState
MethodTable: 00007ffe1079b088
EEClass: 00007ffe107a9dc0
Size: 64(0x40) bytes
File: C:\Program Files\dotnet\shared\Microsoft.NETCore.App\5.0.10\System.IO.FileSystem.Watcher.dll
Fields:MT Field Offset Type VT Attr Value Name
00007ffe104ab258 400002b 30 System.Int32 1 instance 1 Sessionk__BackingField
00007ffe105abf30 400002c 8 System.Byte[] 0 instance 0000016c667c80d0 Bufferk__BackingField
00007ffe106e7a90 400002d 10 ...es.SafeFileHandle 0 instance 0000016c66326028 DirectoryHandlek__BackingField
00007ffe1079c160 400002e 18 ...adPoolBoundHandle 0 instance 0000016c66326058 ThreadPoolBindingk__BackingField
00007ffe107248f0 400002f 20 ...locatedOverlapped 0 instance 0000016c66326090 PreAllocatedOverlappedk__BackingField
00007ffe1079b8c8 4000030 28 ...eSystem.Watcher]] 0 instance 0000016c66326078 WeakWatcherk__BackingField上面的 Bufferk__BackingField 就是当初丢给 OverlappedData 作为 异步IO 读写的缓冲然后看下 System.IO.FileSystemWatcherAsyncReadState 的源码。有了这些原理之后接下来就可以问朋友是否有对 appsettings 设置了 reloadonchangetrue 的情况朋友找了下代码写法大概如下public object GetxxxFlag()
{string value AppConfig.GetConfig(appsettings.json).GetValue(xxxx, 0);return new{state 200,data value};
}public class AppConfig
{public static AppConfig GetConfig(string settingfile appsettings.json){return new AppConfig(settingfile);}
}public class AppConfig
{private AppConfig(string settingfile){_config new ConfigurationBuilder().AddJsonFile(settingfile, optional: true, reloadOnChange: true).Build();_settingfile settingfile;}
}从源码逻辑看我猜测朋友将 GetConfig 方法标记成 static 后就以为是单例化了再次调用不会重复 new AppConfig(settingfile)所以问题就出在这里。不过有意思的是前面二篇的 FileSystemWatcher 都会造成程序卡死那这一篇为啥没有呢恰好他没有在程序根目录中放日志文件不然的话。。。可万万没想到逃过了卡死却没逃过一个 watcher 默认 8byte 空间的灵魂拷问。。。三总结 总的来说设置 reloadOnChange: true 一定要慎重 可能它会造成你的程序卡死句柄泄漏内存泄漏 等等改进方案我就不说了参考我前面的系列文章吧。END工作中的你是否已遇到 ... 1. CPU爆高2. 内存暴涨3. 资源泄漏4. 崩溃死锁5. 程序呆滞等紧急事件全公司都指望着你能解决... 危难时刻才能展现你的技术价值作为专注于.NET高级调试的技术博主欢迎微信搜索: 一线码农聊技术免费协助你分析Dump文件希望我能将你的踩坑经验分享给更多的人。
