"Internal" in java native memory tracking output

Question

The resident size of my application seems to be growing. Native memory tracking shows "Internal" as the one taking unaccounted memory. What is stored in "internal"? [EDIT start] Any parameters to cap its usage? [EDIT end]

Native Memory Tracking:

Total: reserved=31738149KB, committed=31345701KB
-                 Java Heap (reserved=23068672KB, committed=23068672KB)
                            (mmap: reserved=23068672KB, committed=23068672KB) 

-                     Class (reserved=328745KB, committed=77737KB)
                            (classes #12946)
                            (malloc=3113KB #51815) 
                            (mmap: reserved=325632KB, committed=74624KB) 

-                    Thread (reserved=81139KB, committed=81139KB)
                            (thread #136)
                            (stack: reserved=79900KB, committed=79900KB)
                            (malloc=441KB #691) 
                            (arena=797KB #270)

-                      Code (reserved=218074KB, committed=76634KB)
                            (malloc=10074KB #12601) 
                            (mmap: reserved=208000KB, committed=66560KB) 

-                        GC (reserved=177074KB, committed=177074KB)
                            (malloc=127914KB #2258) 
                            (mmap: reserved=49160KB, committed=49160KB) 

-                  Compiler (reserved=549KB, committed=549KB)
                            (malloc=419KB #931) 
                            (arena=131KB #3)

-                  Internal (reserved=7590518KB, committed=7590518KB)
                            (malloc=7590486KB #12185456) 
                            (mmap: reserved=32KB, committed=32KB) 

-                    Symbol (reserved=13995KB, committed=13995KB)
                            (malloc=10535KB #104601) 
                            (arena=3460KB #1)

-    Native Memory Tracking (reserved=193128KB, committed=193128KB)
                            (malloc=19KB #212) 
                            (tracking overhead=193109KB)

-               Arena Chunk (reserved=200KB, committed=200KB)
                            (malloc=200KB) 

-                   Unknown (reserved=66056KB, committed=66056KB)
                            (mmap: reserved=66056KB, committed=66056KB) 

Answer 1

Documented, but not easily searchable -

https://docs.oracle.com/javase/8/docs/technotes/guides/troubleshoot/tooldescr022.html#BABHIFJC