JVM_FindSignal 函数连续分配本机内存
JVM_FindSignal function continuously allocates native memory
我的 java Web 应用程序部署在 linux 机器上的 tomcat8 中，一直在泄漏本机内存，我试图通过使用 jemalloc 分析来检测泄漏源，如下所述：https://github.com/jeffgriffith/native-jvm-leaks
分析工具在服务器 运行 上超过 24 小时的堆转储输出：
Total: 794708494 B
789734456 99.4% 99.4% 789987533 99.4% JVM_FindSignal
3421211 0.4% 99.8% 3421211 0.4% Java_java_util_zip_ZipFile_getZipMessage
1036965 0.1% 99.9% 1036965 0.1% inflateBackEnd
262784 0.0% 100.0% 262784 0.0% __GI__dl_allocate_tls
253077 0.0% 100.0% 598675182 75.3% SUNWprivate_1.1
0 0.0% 100.0% 938397 0.1% 0x00007fb133688ef8
0 0.0% 100.0% 131136 0.0% 0x00007fb133696c2e
0 0.0% 100.0% 6146839 0.8% 0x00007fb13369b553
0 0.0% 100.0% 135210 0.0% 0x00007fb1336a63f5
0 0.0% 100.0% 131136 0.0% 0x00007fb1336a6403
0 0.0% 100.0% 266290 0.0% 0x00007fb1336a7819
0 0.0% 100.0% 296275 0.0% 0x00007fb1336a7827
0 0.0% 100.0% 139434 0.0% 0x00007fb1336a845a
0 0.0% 100.0% 1221269 0.2% 0x00007fb1336a87e9
0 0.0% 100.0% 663829 0.1% 0x00007fb1336a87f7
0 0.0% 100.0% 148137 0.0% 0x00007fb1336a89f7
0 0.0% 100.0% 143743 0.0% 0x00007fb1336a9068
0 0.0% 100.0% 270421 0.0% 0x00007fb1336ab23d
0 0.0% 100.0% 135210 0.0% 0x00007fb1336ab24b
0 0.0% 100.0% 135210 0.0% 0x00007fb1336ab38b
0 0.0% 100.0% 132613 0.0% 0x00007fb1336cb294
0 0.0% 100.0% 131232 0.0% 0x00007fb1336f04da
0 0.0% 100.0% 136258 0.0% 0x00007fb133925efe
0 0.0% 100.0% 135210 0.0% 0x00007fb133927cc6
0 0.0% 100.0% 2012412 0.3% 0x00007fb133929d07
0 0.0% 100.0% 159413372 20.1% 0x00007fb1339be9a5
0 0.0% 100.0% 279249 0.0% 0x00007fb1339e897b
0 0.0% 100.0% 148137 0.0% 0x00007fb133a94545
0 0.0% 100.0% 131232 0.0% 0x00007fb133a980d4
0 0.0% 100.0% 266346 0.0% 0x00007fb133ab523b
0 0.0% 100.0% 444413 0.1% 0x00007fb133ac8727
0 0.0% 100.0% 4622703 0.6% 0x00007fb133b4c74a
0 0.0% 100.0% 270666 0.0% 0x00007fb133b91ee7
0 0.0% 100.0% 28347870 3.6% 0x00007fb133c61c4a
0 0.0% 100.0% 135210 0.0% 0x00007fb133c94425
0 0.0% 100.0% 3064228 0.4% 0x00007fb133d7c611
0 0.0% 100.0% 131080 0.0% 0x00007fb133dfc067
0 0.0% 100.0% 270421 0.0% 0x00007fb133dfc9f3
0 0.0% 100.0% 136258 0.0% 0x00007fb1340590c9
0 0.0% 100.0% 136258 0.0% 0x00007fb1340f60fc
0 0.0% 100.0% 676053 0.1% 0x00007fb13447aba7
0 0.0% 100.0% 968594 0.1% 0x00007fb13467ff67
0 0.0% 100.0% 136258 0.0% 0x00007fb134b8eba6
0 0.0% 100.0% 431231 0.1% 0x00007fb134c861a7
0 0.0% 100.0% 136258 0.0% 0x00007fb135122400
0 0.0% 100.0% 136258 0.0% 0x00007fb1352166b4
0 0.0% 100.0% 136258 0.0% 0x00007fb135807a38
0 0.0% 100.0% 136258 0.0% 0x00007fb135807ed1
0 0.0% 100.0% 136258 0.0% 0x00007fb135822eaf
0 0.0% 100.0% 297823 0.0% 0x00007fb135f85154
0 0.0% 100.0% 136258 0.0% 0x00007fb1368a7c42
0 0.0% 100.0% 1313955 0.2% 0x00007fb136e464e5
0 0.0% 100.0% 922058 0.1% 0x00007fb137245e69
0 0.0% 100.0% 408775 0.1% 0x00007fb13734a4aa
0 0.0% 100.0% 1226327 0.2% 0x00007fb13734a4d3
0 0.0% 100.0% 272517 0.0% 0x00007fb137e0760f
0 0.0% 100.0% 681293 0.1% 0x00007fb137e07624
0 0.0% 100.0% 272517 0.0% 0x00007fb137ea88f5
0 0.0% 100.0% 136258 0.0% 0x00007fb137ea8aa4
0 0.0% 100.0% 136258 0.0% 0x00007fb13876c9e9
0 0.0% 100.0% 136258 0.0% 0x00007fb138c0e8f0
0 0.0% 100.0% 272517 0.0% 0x00007fb138dca6f7
0 0.0% 100.0% 272517 0.0% 0x00007fb138dca70c
0 0.0% 100.0% 272517 0.0% 0x00007fb138dcb5ca
0 0.0% 100.0% 136258 0.0% 0x00007fb138f0dba8
0 0.0% 100.0% 136258 0.0% 0x00007fb138fe8f2e
0 0.0% 100.0% 136258 0.0% 0x00007fb13948cd05
0 0.0% 100.0% 136258 0.0% 0x00007fb139ee2f9c
0 0.0% 100.0% 408775 0.1% 0x00007fb13a03f0be
0 0.0% 100.0% 545034 0.1% 0x00007fb13a04e468
0 0.0% 100.0% 272517 0.0% 0x00007fb13a04e64e
0 0.0% 100.0% 136258 0.0% 0x00007fb13a920fca
0 0.0% 100.0% 136258 0.0% 0x00007fb13a92130b
0 0.0% 100.0% 136258 0.0% 0x00007fb13af0b151
0 0.0% 100.0% 136258 0.0% 0x00007fb13b7609a2
0 0.0% 100.0% 136258 0.0% 0x00007fb13b770cb0
0 0.0% 100.0% 408775 0.1% 0x00007fb13bd55409
0 0.0% 100.0% 136258 0.0% 0x00007fb13c062aea
0 0.0% 100.0% 136258 0.0% 0x00007fb13c06419a
0 0.0% 100.0% 136258 0.0% 0x00007fb13d264f22
0 0.0% 100.0% 136258 0.0% 0x00007fb13d264f37
0 0.0% 100.0% 136258 0.0% 0x00007fb13d265fc4
0 0.0% 100.0% 408775 0.1% 0x00007fb13d3fb048
0 0.0% 100.0% 698085685 87.8% AsyncGetCallTrace
0 0.0% 100.0% 162799014 20.5% JNI_CreateJavaVM
0 0.0% 100.0% 35102689 4.4% JNI_GetCreatedJavaVMs
0 0.0% 100.0% 131296 0.0% JNU_NewObjectByName
0 0.0% 100.0% 4766447 0.6% JVM_DefineClass
0 0.0% 100.0% 29155153 3.7% JVM_DefineClassWithSource
0 0.0% 100.0% 1204712 0.2% JVM_DoPrivileged
0 0.0% 100.0% 444413 0.1% JVM_FillInStackTrace
0 0.0% 100.0% 266346 0.0% JVM_FindClassFromBootLoader
0 0.0% 100.0% 270421 0.0% JVM_FindClassFromCaller
0 0.0% 100.0% 279249 0.0% JVM_FindLoadedClass
0 0.0% 100.0% 131080 0.0% JVM_GetClassDeclaredConstructors
0 0.0% 100.0% 824436 0.1% JVM_GetClassDeclaredFields
0 0.0% 100.0% 942399 0.1% JVM_GetClassDeclaredMethods
0 0.0% 100.0% 135210 0.0% JVM_GetClassName
0 0.0% 100.0% 159413372 20.1% JVM_InternString
0 0.0% 100.0% 253077 0.0% JVM_LoadLibrary
0 0.0% 100.0% 431231 0.1% JVM_MonitorWait
0 0.0% 100.0% 409855 0.1% JVM_RawMonitorExit
0 0.0% 100.0% 1707451 0.2% JVM_StartThread
0 0.0% 100.0% 714622614 89.9% JVM_handle_linux_signal
0 0.0% 100.0% 253077 0.0% Java_java_lang_ClassLoader_00024NativeLibrary_load
0 0.0% 100.0% 29155153 3.7% Java_java_lang_ClassLoader_defineClass1
0 0.0% 100.0% 266346 0.0% Java_java_lang_ClassLoader_findBootstrapClass
0 0.0% 100.0% 270421 0.0% Java_java_lang_Class_forName0
0 0.0% 100.0% 444413 0.1% Java_java_lang_Throwable_fillInStackTrace
0 0.0% 100.0% 131136 0.0% Java_java_lang_reflect_Proxy_defineClass0
0 0.0% 100.0% 1036965 0.1% Java_java_util_zip_Inflater_inflateBytes
0 0.0% 100.0% 3064228 0.4% Java_java_util_zip_ZipFile_open
0 0.0% 100.0% 131296 0.0% Java_sun_management_Flag_getFlags
0 0.0% 100.0% 356982 0.0% ZIP_Open
0 0.0% 100.0% 3421211 0.4% ZIP_Unlock
0 0.0% 100.0% 569857981 71.7% __clone
0 0.0% 100.0% 253077 0.0% __dlopen_check
0 0.0% 100.0% 262784 0.0% __pthread_create_2_1
0 0.0% 100.0% 253077 0.0% _dl_catch_error
0 0.0% 100.0% 253077 0.0% _dl_init_internal
0 0.0% 100.0% 253077 0.0% _dl_open
0 0.0% 100.0% 253077 0.0% _dlerror_run
0 0.0% 100.0% 253077 0.0% dl_open_worker
0 0.0% 100.0% 253077 0.0% dlopen_doit
0 0.0% 100.0% 393920 0.0% fork1
0 0.0% 100.0% 1036965 0.1% inflate
0 0.0% 100.0% 569857981 71.7% start_thread
如图：
我也用过Java本机内存跟踪工具
查明泄漏 https://docs.oracle.com/javase/8/docs/technotes/guides/vm/nmt-8.html
NMT 报告 'Internal' 部分内存泄漏。
调用图表明调用 JVM_FindSignal 是由于
start_thread，但是，NMT diff 工具报告应用程序线程的数量几乎保持不变并保持在 ~300。
JVM 选项：
-Xms24920m -Xmx24920m -XX:MaxMetaspaceSize=512m -XX:+AlwaysPreTouch
-XX:+UseG1GC -XX:G1HeapWastePercent=10
-XX:+UseTLAB
-XX:+ScavengeBeforeFullGC -verbose:gc
-XX:+PrintGCDetails
-XX:+PrintGCDateStamps -XX:+PrintTenuringDistribution
-XX:+PrintGCApplicationConcurrentTime
-XX:+PrintGCApplicationStoppedTime
-Djava.rmi.server.hostname=XXXXX
-Dcom.sun.management.jmxremote.port=XXXXX
-Dcom.sun.management.jmxremote.ssl=false
所以，JVM_FindSignal 已经分配但未释放 789 兆字节的本机内存，有没有人知道 JVM_FindSignal 做了什么以及为什么它会不断分配内存？
JVM_FindSignal 根本不分配内存。而且此函数通常不会在应用程序 运行 时经常调用。
您的 JDK 安装似乎不包含调试符号，因此 jemalloc 探查器无法找到正确的函数名称，只能从 [=14= 中获取最近的 public 符号]. JVM_FindSignal 只是这些随机符号之一。配置文件中的其他条目看起来也不对。例如。占87.8%的AsyncGetCallTrace也什么都不分配
安装带有 JDK 调试符号的单独包可能会有所帮助。
在 Debian 上/Ubuntu:
apt install openjdk-8-dbg
在 RHEL/CentOS 上：
debuginfo-install java-1.8.0-openjdk
我的 java Web 应用程序部署在 linux 机器上的 tomcat8 中，一直在泄漏本机内存，我试图通过使用 jemalloc 分析来检测泄漏源，如下所述：https://github.com/jeffgriffith/native-jvm-leaks 分析工具在服务器 运行 上超过 24 小时的堆转储输出：
Total: 794708494 B
789734456 99.4% 99.4% 789987533 99.4% JVM_FindSignal
3421211 0.4% 99.8% 3421211 0.4% Java_java_util_zip_ZipFile_getZipMessage
1036965 0.1% 99.9% 1036965 0.1% inflateBackEnd
262784 0.0% 100.0% 262784 0.0% __GI__dl_allocate_tls
253077 0.0% 100.0% 598675182 75.3% SUNWprivate_1.1
0 0.0% 100.0% 938397 0.1% 0x00007fb133688ef8
0 0.0% 100.0% 131136 0.0% 0x00007fb133696c2e
0 0.0% 100.0% 6146839 0.8% 0x00007fb13369b553
0 0.0% 100.0% 135210 0.0% 0x00007fb1336a63f5
0 0.0% 100.0% 131136 0.0% 0x00007fb1336a6403
0 0.0% 100.0% 266290 0.0% 0x00007fb1336a7819
0 0.0% 100.0% 296275 0.0% 0x00007fb1336a7827
0 0.0% 100.0% 139434 0.0% 0x00007fb1336a845a
0 0.0% 100.0% 1221269 0.2% 0x00007fb1336a87e9
0 0.0% 100.0% 663829 0.1% 0x00007fb1336a87f7
0 0.0% 100.0% 148137 0.0% 0x00007fb1336a89f7
0 0.0% 100.0% 143743 0.0% 0x00007fb1336a9068
0 0.0% 100.0% 270421 0.0% 0x00007fb1336ab23d
0 0.0% 100.0% 135210 0.0% 0x00007fb1336ab24b
0 0.0% 100.0% 135210 0.0% 0x00007fb1336ab38b
0 0.0% 100.0% 132613 0.0% 0x00007fb1336cb294
0 0.0% 100.0% 131232 0.0% 0x00007fb1336f04da
0 0.0% 100.0% 136258 0.0% 0x00007fb133925efe
0 0.0% 100.0% 135210 0.0% 0x00007fb133927cc6
0 0.0% 100.0% 2012412 0.3% 0x00007fb133929d07
0 0.0% 100.0% 159413372 20.1% 0x00007fb1339be9a5
0 0.0% 100.0% 279249 0.0% 0x00007fb1339e897b
0 0.0% 100.0% 148137 0.0% 0x00007fb133a94545
0 0.0% 100.0% 131232 0.0% 0x00007fb133a980d4
0 0.0% 100.0% 266346 0.0% 0x00007fb133ab523b
0 0.0% 100.0% 444413 0.1% 0x00007fb133ac8727
0 0.0% 100.0% 4622703 0.6% 0x00007fb133b4c74a
0 0.0% 100.0% 270666 0.0% 0x00007fb133b91ee7
0 0.0% 100.0% 28347870 3.6% 0x00007fb133c61c4a
0 0.0% 100.0% 135210 0.0% 0x00007fb133c94425
0 0.0% 100.0% 3064228 0.4% 0x00007fb133d7c611
0 0.0% 100.0% 131080 0.0% 0x00007fb133dfc067
0 0.0% 100.0% 270421 0.0% 0x00007fb133dfc9f3
0 0.0% 100.0% 136258 0.0% 0x00007fb1340590c9
0 0.0% 100.0% 136258 0.0% 0x00007fb1340f60fc
0 0.0% 100.0% 676053 0.1% 0x00007fb13447aba7
0 0.0% 100.0% 968594 0.1% 0x00007fb13467ff67
0 0.0% 100.0% 136258 0.0% 0x00007fb134b8eba6
0 0.0% 100.0% 431231 0.1% 0x00007fb134c861a7
0 0.0% 100.0% 136258 0.0% 0x00007fb135122400
0 0.0% 100.0% 136258 0.0% 0x00007fb1352166b4
0 0.0% 100.0% 136258 0.0% 0x00007fb135807a38
0 0.0% 100.0% 136258 0.0% 0x00007fb135807ed1
0 0.0% 100.0% 136258 0.0% 0x00007fb135822eaf
0 0.0% 100.0% 297823 0.0% 0x00007fb135f85154
0 0.0% 100.0% 136258 0.0% 0x00007fb1368a7c42
0 0.0% 100.0% 1313955 0.2% 0x00007fb136e464e5
0 0.0% 100.0% 922058 0.1% 0x00007fb137245e69
0 0.0% 100.0% 408775 0.1% 0x00007fb13734a4aa
0 0.0% 100.0% 1226327 0.2% 0x00007fb13734a4d3
0 0.0% 100.0% 272517 0.0% 0x00007fb137e0760f
0 0.0% 100.0% 681293 0.1% 0x00007fb137e07624
0 0.0% 100.0% 272517 0.0% 0x00007fb137ea88f5
0 0.0% 100.0% 136258 0.0% 0x00007fb137ea8aa4
0 0.0% 100.0% 136258 0.0% 0x00007fb13876c9e9
0 0.0% 100.0% 136258 0.0% 0x00007fb138c0e8f0
0 0.0% 100.0% 272517 0.0% 0x00007fb138dca6f7
0 0.0% 100.0% 272517 0.0% 0x00007fb138dca70c
0 0.0% 100.0% 272517 0.0% 0x00007fb138dcb5ca
0 0.0% 100.0% 136258 0.0% 0x00007fb138f0dba8
0 0.0% 100.0% 136258 0.0% 0x00007fb138fe8f2e
0 0.0% 100.0% 136258 0.0% 0x00007fb13948cd05
0 0.0% 100.0% 136258 0.0% 0x00007fb139ee2f9c
0 0.0% 100.0% 408775 0.1% 0x00007fb13a03f0be
0 0.0% 100.0% 545034 0.1% 0x00007fb13a04e468
0 0.0% 100.0% 272517 0.0% 0x00007fb13a04e64e
0 0.0% 100.0% 136258 0.0% 0x00007fb13a920fca
0 0.0% 100.0% 136258 0.0% 0x00007fb13a92130b
0 0.0% 100.0% 136258 0.0% 0x00007fb13af0b151
0 0.0% 100.0% 136258 0.0% 0x00007fb13b7609a2
0 0.0% 100.0% 136258 0.0% 0x00007fb13b770cb0
0 0.0% 100.0% 408775 0.1% 0x00007fb13bd55409
0 0.0% 100.0% 136258 0.0% 0x00007fb13c062aea
0 0.0% 100.0% 136258 0.0% 0x00007fb13c06419a
0 0.0% 100.0% 136258 0.0% 0x00007fb13d264f22
0 0.0% 100.0% 136258 0.0% 0x00007fb13d264f37
0 0.0% 100.0% 136258 0.0% 0x00007fb13d265fc4
0 0.0% 100.0% 408775 0.1% 0x00007fb13d3fb048
0 0.0% 100.0% 698085685 87.8% AsyncGetCallTrace
0 0.0% 100.0% 162799014 20.5% JNI_CreateJavaVM
0 0.0% 100.0% 35102689 4.4% JNI_GetCreatedJavaVMs
0 0.0% 100.0% 131296 0.0% JNU_NewObjectByName
0 0.0% 100.0% 4766447 0.6% JVM_DefineClass
0 0.0% 100.0% 29155153 3.7% JVM_DefineClassWithSource
0 0.0% 100.0% 1204712 0.2% JVM_DoPrivileged
0 0.0% 100.0% 444413 0.1% JVM_FillInStackTrace
0 0.0% 100.0% 266346 0.0% JVM_FindClassFromBootLoader
0 0.0% 100.0% 270421 0.0% JVM_FindClassFromCaller
0 0.0% 100.0% 279249 0.0% JVM_FindLoadedClass
0 0.0% 100.0% 131080 0.0% JVM_GetClassDeclaredConstructors
0 0.0% 100.0% 824436 0.1% JVM_GetClassDeclaredFields
0 0.0% 100.0% 942399 0.1% JVM_GetClassDeclaredMethods
0 0.0% 100.0% 135210 0.0% JVM_GetClassName
0 0.0% 100.0% 159413372 20.1% JVM_InternString
0 0.0% 100.0% 253077 0.0% JVM_LoadLibrary
0 0.0% 100.0% 431231 0.1% JVM_MonitorWait
0 0.0% 100.0% 409855 0.1% JVM_RawMonitorExit
0 0.0% 100.0% 1707451 0.2% JVM_StartThread
0 0.0% 100.0% 714622614 89.9% JVM_handle_linux_signal
0 0.0% 100.0% 253077 0.0% Java_java_lang_ClassLoader_00024NativeLibrary_load
0 0.0% 100.0% 29155153 3.7% Java_java_lang_ClassLoader_defineClass1
0 0.0% 100.0% 266346 0.0% Java_java_lang_ClassLoader_findBootstrapClass
0 0.0% 100.0% 270421 0.0% Java_java_lang_Class_forName0
0 0.0% 100.0% 444413 0.1% Java_java_lang_Throwable_fillInStackTrace
0 0.0% 100.0% 131136 0.0% Java_java_lang_reflect_Proxy_defineClass0
0 0.0% 100.0% 1036965 0.1% Java_java_util_zip_Inflater_inflateBytes
0 0.0% 100.0% 3064228 0.4% Java_java_util_zip_ZipFile_open
0 0.0% 100.0% 131296 0.0% Java_sun_management_Flag_getFlags
0 0.0% 100.0% 356982 0.0% ZIP_Open
0 0.0% 100.0% 3421211 0.4% ZIP_Unlock
0 0.0% 100.0% 569857981 71.7% __clone
0 0.0% 100.0% 253077 0.0% __dlopen_check
0 0.0% 100.0% 262784 0.0% __pthread_create_2_1
0 0.0% 100.0% 253077 0.0% _dl_catch_error
0 0.0% 100.0% 253077 0.0% _dl_init_internal
0 0.0% 100.0% 253077 0.0% _dl_open
0 0.0% 100.0% 253077 0.0% _dlerror_run
0 0.0% 100.0% 253077 0.0% dl_open_worker
0 0.0% 100.0% 253077 0.0% dlopen_doit
0 0.0% 100.0% 393920 0.0% fork1
0 0.0% 100.0% 1036965 0.1% inflate
0 0.0% 100.0% 569857981 71.7% start_thread
如图：
我也用过Java本机内存跟踪工具 查明泄漏 https://docs.oracle.com/javase/8/docs/technotes/guides/vm/nmt-8.html NMT 报告 'Internal' 部分内存泄漏。 调用图表明调用 JVM_FindSignal 是由于 start_thread，但是，NMT diff 工具报告应用程序线程的数量几乎保持不变并保持在 ~300。
JVM 选项：
-Xms24920m -Xmx24920m -XX:MaxMetaspaceSize=512m -XX:+AlwaysPreTouch
-XX:+UseG1GC -XX:G1HeapWastePercent=10
-XX:+UseTLAB
-XX:+ScavengeBeforeFullGC -verbose:gc
-XX:+PrintGCDetails
-XX:+PrintGCDateStamps -XX:+PrintTenuringDistribution
-XX:+PrintGCApplicationConcurrentTime
-XX:+PrintGCApplicationStoppedTime
-Djava.rmi.server.hostname=XXXXX
-Dcom.sun.management.jmxremote.port=XXXXX
-Dcom.sun.management.jmxremote.ssl=false
所以，JVM_FindSignal 已经分配但未释放 789 兆字节的本机内存，有没有人知道 JVM_FindSignal 做了什么以及为什么它会不断分配内存？
JVM_FindSignal 根本不分配内存。而且此函数通常不会在应用程序 运行 时经常调用。
您的 JDK 安装似乎不包含调试符号，因此 jemalloc 探查器无法找到正确的函数名称，只能从 [=14= 中获取最近的 public 符号]. JVM_FindSignal 只是这些随机符号之一。配置文件中的其他条目看起来也不对。例如。占87.8%的AsyncGetCallTrace也什么都不分配
安装带有 JDK 调试符号的单独包可能会有所帮助。
在 Debian 上/Ubuntu:
apt install openjdk-8-dbg
在 RHEL/CentOS 上：
debuginfo-install java-1.8.0-openjdk