memory-leaks - Ninject 中的内存泄漏

Question

我正在通过使用 Windbg 分析内存转储来调查运行高达 10GB 内存的 Web 应用。

这是 !dumpheap -stat 输出的底部:

00007ff9545df5d0   166523     13321840 System.Runtime.Caching.MemoryCache
00007ff9545df4a0   166523     14654024 System.Runtime.Caching.CacheMemoryMonitor
00007ff9545de990   166523     14654024 System.Runtime.Caching.SRef[]
00007ff9545dcef0   166523     14654024 System.Runtime.Caching.GCHandleRef`1[[System.Runtime.Caching.MemoryCacheStore, System.Runtime.Caching]][]
00007ff9545dfb28   166523     19982760 System.Runtime.Caching.MemoryCacheStatistics
00007ff956778510   333059     21315680 System.Int64[]
00007ff95679c988    41597     31250111 System.Byte[]
00007ff9545e08c8  1332184     31972416 System.Runtime.Caching.MemoryCacheEqualityComparer
00007ff9545dfe48  1332184     31972416 System.Runtime.Caching.SRef
00007ff956780ff0  1332200     31972800 System.SizedReference
00007ff956724620  1498777     35970648 System.Threading.TimerHolder
00007ff95677fb30  1536170     36868080 System.Runtime.Remoting.Messaging.CallContextSecurityData
00007ff956796f28  1606960     38567040 System.Object
00007ff9545df810  1332184     42629888 System.Runtime.Caching.GCHandleRef`1[[System.Runtime.Caching.MemoryCacheStore, System.Runtime.Caching]]
00007ff9545dda38  1332184     42629888 System.Runtime.Caching.UsageBucket[]
00007ff9567ae930  1332268     42632576 Microsoft.Win32.SafeHandles.SafeWaitHandle
00007ff9545df968  1498707     47958624 System.Runtime.Caching.GCHandleRef`1[[System.Threading.Timer, mscorlib]]
00007ff9567adbf8  1498777     47960864 System.Threading.Timer
00007ff9545dff50  1332184     53287360 System.Runtime.Caching.CacheUsage
00007ff94986ead8  1536137     61445480 System.Web.Hosting.AspNetHostExecutionContextManager+AspNetHostExecutionContext
00007ff9567a2838  1332210     63946080 System.Threading.ManualResetEvent
00007ff956796948   293525     66384986 System.String
00007ff9545dfef0  1332184     74602304 System.Runtime.Caching.CacheExpires
00007ff9567add20  1498760     95920640 System.Threading.TimerCallback
00007ff9545dfa90  1332184    106574720 System.Runtime.Caching.MemoryCacheStore
00007ff95679b3b0  1333289    106663120 System.Collections.Hashtable
00007ff95678f138  1536171    110604312 System.Runtime.Remoting.Messaging.LogicalCallContext
00007ff9545dffb0  1332184    127889664 System.Runtime.Caching.UsageBucket
00007ff95679d1e0  1333292    128664768 System.Collections.Hashtable+bucket[]
00007ff9567245c0  1498777    131892376 System.Threading.TimerQueueTimer
00007ff9567aec48  1536255    135190440 System.Threading.ExecutionContext
00007ff9545dcf78  1332184    351696576 System.Runtime.Caching.ExpiresBucket[]
000000f82c79d9f0   473339    385303992      Free
00007ff956799220 40309535   1617342672 System.Int32[]
00007ff9545e0468 39965520   3836689920 System.Runtime.Caching.ExpiresBucket

所以 System.Runtime.Caching.ExpiresBucket 有将近 4000 万个实例，总共使用了将近 4gb 的内存。 System.Runtime.Caching 类在最常见的违规者中出现了很多。

我取了一个 System.Runtime.Caching.ExpiresBucket 类的随机实例，并对其执行了 !gcroot。生成 1 个线程需要很长时间(可能需要 30 分钟)……可能还有更多线程，但此时我中断了操作。

引用链超过 150 万行!但我可以在这里展示重要的部分:

0:000> !gcroot 000000f82dd4bc28
Thread 1964:
    000000fcbdbce6a0 00007ff8f9bbe388 Microsoft.AspNet.SignalR.SqlServer.ObservableDbOperation.ExecuteReaderWithUpdates(System.Action`2<System.Data.IDataRecord,Microsoft.AspNet.SignalR.SqlServer.DbOperation>)
        rbp-58: 000000fcbdbce6e8
            ->  000000fa2d1f26a0 Microsoft.AspNet.SignalR.SqlServer.ObservableDbOperation+<>c__DisplayClass1e
            ->  000000fa2d1f2110 Microsoft.AspNet.SignalR.SqlServer.ObservableDbOperation
            ->  000000fa2d1f24d0 System.Action
            ->  000000fa2d1f24a8 System.Object[]
            ->  000000fa2d1f2468 System.Action
            ->  000000fa2d1f1008 Microsoft.AspNet.SignalR.SqlServer.SqlReceiver
            ->  000000fa2d1f1330 System.Action
            ->  000000fa2d1f1308 System.Object[]
            ->  000000fa2d1f12c8 System.Action
            ->  000000fa2d1efb70 Microsoft.AspNet.SignalR.SqlServer.SqlStream
            ->  000000fa2d1f1528 System.Action
            ->  000000fa2d1f1500 System.Object[]
            ->  000000fa2d1f14c0 System.Action
            ->  000000fa2d1efb20 Microsoft.AspNet.SignalR.SqlServer.SqlMessageBus+<>c__DisplayClass3
            ->  000000f92d0b84e0 Microsoft.AspNet.SignalR.SqlServer.SqlMessageBus
            ->  000000f92d0b9568 System.Threading.Timer
            ->  000000f92d0b96d8 System.Threading.TimerHolder
            ->  000000f92d0b95a0 System.Threading.TimerQueueTimer
[... about 100 lines of the same TimerQueueTimer line above, but different memory addresses each time]
           ->  000000f92cf1be68 System.Threading.TimerQueueTimer
            ->  000000f92cf1be08 System.Threading.TimerCallback
            ->  000000f92cf1bb48 System.Web.RequestTimeoutManager
            ->  000000f92cf1bb80 System.Web.Util.DoubleLinkList[]
            ->  000000f92cf1bc00 System.Web.Util.DoubleLinkList
            ->  000000fb61323860 System.Web.RequestTimeoutManager+RequestTimeoutEntry
            ->  000000fb6131fd38 System.Web.HttpContext
            ->  000000fbe682a480 ASP.global_asax
            ->  000000fbe682ac00 System.Web.HttpModuleCollection
            ->  000000fbe682ac60 System.Collections.ArrayList
            ->  000000fbe682b598 System.Object[]
            ->  000000fbe682b018 System.Collections.Specialized.NameObjectCollectionBase+NameObjectEntry
            ->  000000fbe682b000 System.Web.Routing.UrlRoutingModule
            ->  000000faacec1f40 System.Web.Routing.RouteCollection
            ->  000000faacec2030 System.Collections.Generic.List`1[[System.Web.Routing.RouteBase, System.Web]]
            ->  000000fa2cfe4d80 System.Web.Routing.RouteBase[]
            ->  000000f9acf14cd8 System.Web.Http.WebHost.Routing.HttpWebRoute
            ->  000000f9acf149f8 System.Web.Http.Routing.RouteCollectionRoute
            ->  000000f9acf1f4f0 System.Web.Http.Routing.SubRouteCollection
            ->  000000f9acf1f510 System.Collections.Generic.List`1[[System.Web.Http.Routing.IHttpRoute, System.Web.Http]]
            ->  000000fa2cf8f310 System.Web.Http.Routing.IHttpRoute[]
            ->  000000fa2ceff770 System.Web.Http.Routing.HttpRoute
            ->  000000fa2ceff678 System.Web.Http.Routing.HttpRouteValueDictionary
            ->  000000fa2ceff6f0 System.Collections.Generic.Dictionary`2+Entry[[System.String, mscorlib],[System.Object, mscorlib]][]
            ->  000000fa2cef9e78 System.Web.Http.Controllers.HttpActionDescriptor[]
            ->  000000fa2cef7898 System.Web.Http.Controllers.ReflectedHttpActionDescriptor
            ->  000000f9aced4608 System.Web.Http.HttpConfiguration
            ->  000000f9aced4db0 System.Net.Http.Formatting.MediaTypeFormatterCollection
            ->  000000f9aced6f40 System.Collections.Generic.List`1[[System.Net.Http.Formatting.MediaTypeFormatter, System.Net.Http.Formatting]]
            ->  000000f9aced6f80 System.Net.Http.Formatting.MediaTypeFormatter[]
            ->  000000f9aced4df8 System.Net.Http.Formatting.JsonMediaTypeFormatter
            ->  000000f9acf1f448 System.Web.Http.Validation.ModelValidationRequiredMemberSelector
            ->  000000f9acf1f468 System.Collections.Generic.List`1[[System.Web.Http.Validation.ModelValidatorProvider, System.Web.Http]]
            ->  000000f9acf1f490 System.Web.Http.Validation.ModelValidatorProvider[]
            ->  000000f9acf1db40 Ninject.Web.WebApi.Validation.NinjectDefaultModelValidatorProvider
            ->  000000faaceca438 Ninject.StandardKernel
            ->  000000faaceca498 Ninject.Components.ComponentContainer
            ->  000000faaceca538 System.Collections.Generic.Dictionary`2[[System.Type, mscorlib],[Ninject.Components.INinjectComponent, Ninject]]
            ->  000000f9acece000 System.Collections.Generic.Dictionary`2+Entry[[System.Type, mscorlib],[Ninject.Components.INinjectComponent, Ninject]][]
            ->  000000f9acecdac8 Ninject.Activation.Caching.GarbageCollectionCachePruner
            ->  000000f9acecdcb8 System.Threading.Timer
            ->  000000f9acecdd30 System.Threading.TimerHolder
            ->  000000f9acecdcd8 System.Threading.TimerQueueTimer
[... just under 1.5 million lines of the same TimerQueueTimer line above, but different memory addresses each time]
            ->  000000f82dd4c028 System.Threading.TimerQueueTimer
            ->  000000f82dd4bfc8 System.Threading.TimerCallback
            ->  000000f82dd4ada0 System.Runtime.Caching.CacheExpires
            ->  000000f82dd4add8 System.Runtime.Caching.ExpiresBucket[]
            ->  000000f82dd4bc28 System.Runtime.Caching.ExpiresBucket

在 000000faaceca438 Ninject.StandardKernel 上运行 !objsize 似乎要花很长时间，这意味着它引用了非常多的对象，可能所有 4000 万个 System.Runtime.Caching.ExpiresBucket 对象...

是什么导致泄漏？我应该如何识别有问题的类或代码？在 gcroot 输出中没有引用我们自己的任何代码，这是由于我们正在使用的已安装库之一中的错误吗？它在 Ninject 中吗？我们使用的是 v3.2.2(我知道不是最新的)

Answer 1

作为答案发布，因为评论太长了:

在我看来，Ninject 正在跟踪大量范围对象。 AFAIR 这就是 GarbageCollectionPruner 的用途。作用域对象是用 .InScope(...this object here...) 或一些重载如 InRequestScope() 定义的对象。GarbageCollectionPruner 有一个计时器，它会定期检查范围是否仍然“有效”。如果它不再存在(收集垃圾)，它将处理并忘记与该范围关联的所有对象。

除非 ninject 中没有错误，否则这意味着您的应用程序会在短时间内创建大量作用域或者它们没有被正确清理(意思是:您或其他第 3 层的问题党代码)。

顺便说一句，如果作用域对象实现了INotifyWhenDisposed(ninject 接口(interface))，那么周期性的IsAlive 检查就没有必要了，而且还提供了“确定性”处置的好处，即就在范围结束时，范围内的对象也会被释放。否则这取决于 Ninject 中的 GC 和计时器......