NativeMemoryTracking查看java内存信息

默认该功能是禁用的，因为会损失5-10%的性能

开启命令

-XX:NativeMemoryTracking=detail

打印命令

jcmd 45064 VM.native_memory summary scale=MB > NativeMemoryTracking.log

具体的日志信息

➜  ~
➜  ~ jcmd 45064 VM.native_memory summary scale=MB
45064:

Native Memory Tracking:

(Omitting categories weighting less than 1MB)

Total: reserved=5676MB, committed=654MB
       malloc: 58MB #363115
       mmap:   reserved=5618MB, committed=596MB

-                 Java Heap (reserved=4096MB, committed=200MB)
                            (mmap: reserved=4096MB, committed=200MB)

-                     Class (reserved=1025MB, committed=11MB)
                            (classes #16551)
                            (  instance classes #15574, array classes #977)
                            (malloc=1MB #44456)
                            (mmap: reserved=1024MB, committed=10MB)
                            (  Metadata:   )
                            (    reserved=64MB, committed=63MB)
                            (    used=62MB)
                            (    waste=1MB =0.90%)
                            (  Class space:)
                            (    reserved=1024MB, committed=10MB)
                            (    used=9MB)
                            (    waste=0MB =3.79%)

-                    Thread (reserved=258MB, committed=258MB)
                            (thread #129)
                            (stack: reserved=258MB, committed=258MB)

-                      Code (reserved=50MB, committed=19MB)
                            (malloc=2MB #10874)
                            (mmap: reserved=48MB, committed=17MB)

-                        GC (reserved=130MB, committed=54MB)
                            (malloc=17MB #9999)
                            (mmap: reserved=112MB, committed=36MB)

-                  Internal (reserved=1MB, committed=1MB)
                            (malloc=1MB #18262)

-                    Symbol (reserved=26MB, committed=26MB)
                            (malloc=22MB #218120)
                            (arena=4MB #1)

-    Native Memory Tracking (reserved=6MB, committed=6MB)
                            (tracking overhead=6MB)

-        Shared class space (reserved=16MB, committed=13MB, readonly=0MB)
                            (mmap: reserved=16MB, committed=13MB)

-           Synchronization (reserved=3MB, committed=3MB)
                            (malloc=3MB #50578)

-                 Metaspace (reserved=64MB, committed=63MB)
                            (mmap: reserved=64MB, committed=63MB)

堆外内存异常问题排查

https://www.cnblogs.com/duanxz/p/3738858.html

Native Memory Tracking 详解（1）:基础介绍 | HeapDump性能社区

原文地址：https://blog.csdn.net/wppwpp1/article/details/140135923

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