网络应用记忆消耗

Question

我的应用程序是用netty编写的，最近被oom killer杀死。我不确定是否存在内存泄漏。

我的Linux服务具有4 cpu和8G内存。我正在运行tomcat和netty程序。 netty APP有我的JVM标志：

VM Flags: Non-default VM flags: -XX:CICompilerCount=3 -XX:GCLogFileSize=10485760 -XX:InitialHeapSize=3221225472 -XX:MaxHeapSize=3221225472 -XX:MaxNewSize=1073741824 -XX:MinHeapDeltaBytes=524288 -XX:NativeMemoryTracking=null -XX:NewSize=1073741824 -XX:NumberOfGCLogFiles=10 -XX:OldSize=2147483648 -XX:+PrintGC -XX:+PrintGCDateStamps -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -XX:+UseCompressedClassPointers -XX:+UseCompressedOops -XX:+UseGCLogFileRotation -XX:+UseParallelGC

如您所见，我使用NMT跟踪内部内存使用情况，并且每分钟记录摘要数据。

Sat Dec 22 17:48:01 CST 2018
11568:
Native Memory Tracking:
Total:  reserved=4748707KB,  committed=3474051KB
             Java Heap (reserved=3145728KB, committed=3145728KB)
                        (mmap: reserved=3145728KB, committed=3145728KB)

                 Class (reserved=1076807KB, committed=31047KB)
                        (classes #3973)
                        (malloc=5703KB, #7662)
                        (mmap: reserved=1071104KB, committed=25344KB)

                Thread (reserved=53715KB, committed=53715KB)
                        (thread #52)
                        (stack: reserved=53456KB, committed=53456KB)
                        (malloc=166KB, #266)
                        (arena=93KB, #104)

                  Code (reserved=253349KB, committed=24485KB)
                        (malloc=3749KB, #5611)
                        (mmap: reserved=249600KB, committed=20736KB)

                    GC (reserved=120705KB, committed=120705KB)
                        (malloc=5773KB, #165)
                        (mmap: reserved=114932KB, committed=114932KB)

              Compiler (reserved=231KB, committed=231KB)
                        (malloc=132KB, #259)
                        (arena=99KB, #3)

              Internal (reserved=72938KB, committed=72906KB)
                        (malloc=72906KB, #5771)
                        (mmap: reserved=32KB, committed=0KB)

                Symbol (reserved=5690KB, committed=5690KB)
                        (malloc=4020KB, #30930)
                        (arena=1670KB, #1)

       Memory Tracking (reserved=4962KB, committed=4962KB)
                        (malloc=4962KB, #232)

    Pooled Free Chunks (reserved=14581KB, committed=14581KB)
                        (malloc=14581KB)

我在12月22日启动该应用程序，Internal memory只有72906KB。但是，当我在12月24日获得最新数据时，Internal memory的大小为2041923KB，几乎是12月22日数据的30倍。

Mon Dec 24 14:55:01 CST 2018
11568:

Native Memory Tracking:

Total:  reserved=6707204KB,  committed=5432760KB

             Java Heap (reserved=3145728KB, committed=3145728KB)
                        (mmap: reserved=3145728KB, committed=3145728KB)

                 Class (reserved=1078933KB, committed=32149KB)
                        (classes #4035)
                        (malloc=5781KB, #9741)
                        (mmap: reserved=1073152KB, committed=26368KB)

                Thread (reserved=54779KB, committed=54779KB)
                        (thread #53)
                        (stack: reserved=54484KB, committed=54484KB)
                        (malloc=169KB, #271)
                        (arena=126KB, #106)

                  Code (reserved=253940KB, committed=26312KB)
                        (malloc=4340KB, #6484)
                        (mmap: reserved=249600KB, committed=21972KB)

                    GC (reserved=120704KB, committed=120704KB)
                        (malloc=5772KB, #149)
                        (mmap: reserved=114932KB, committed=114932KB)

              Compiler (reserved=277KB, committed=277KB)
                        (malloc=178KB, #281)
                        (arena=99KB, #3)

              Internal (reserved=2041955KB, committed=2041923KB)
                        (malloc=2041923KB, #6058)
                        (mmap: reserved=32KB, committed=0KB)

                Symbol (reserved=5771KB, committed=5771KB)
                        (malloc=4069KB, #31110)
                        (arena=1702KB, #1)

       Memory Tracking (reserved=4962KB, committed=4962KB)
                        (malloc=4962KB, #222)

    Pooled Free Chunks (reserved=156KB, committed=156KB)
                        (malloc=156KB)

因此，netty应用程序占用的内存超过5G（堆3G +内部2G）。服务器的内存即将用完

top - 15:42:37 up 384 days, 22:55,  1 user,  load average: 0.84, 0.90, 0.94
Tasks: 108 total,   1 running, 107 sleeping,   0 stopped,   0 zombie  
%Cpu(s): 15.7 us,  4.9 sy,  0.0 ni, 76.7 id,  0.0 wa,  0.0 hi,  2.7 si,0.0 st
KiB Mem :  8010424 total,   123472 free,  7481940 used,   405012 buff/cache
KiB Swap:        0 total,        0 free,        0 used.   155052 avail Mem