Native heap usage

The native heap usage will normally grow to a stable level, and then stay at around that level. You can monitor the amount of memory committed to the native heap by observing the number of 'Inuse' pages in the svmon output.

However, note that as JIT compiled code is allocated to the native heap with malloc(), there might be a steady slow increase in native heap usage as little used methods reach the threshold to undergo JIT compilation.

You can monitor the JIT compiling of code to avoid confusing this behavior with a memory leak. To do this, run with the command-line option -Xjit:verbose={compileStart|compileEnd}. This command causes each method name to print to stderr as it is being compiled and, as it finishes compiling, the location in memory where the compiled code is stored.

(warm) Compiling java/lang/System.getEncoding(I)Ljava/lang/String; 
+ (warm) java/lang/System.getEncoding(I)Ljava/lang/String; @ 0x02BA0028-0x02BA0113   
                                        (2) Compiling java/lang/String.hashCode()I 
+ (warm) java/lang/String.hashCode()I @ 0x02BA0150-0x02BA0229   
  (2) Compiling java/util/HashMap.put(Ljava/lang/Object;Ljava/lang/Object;)
   Ljava/lang/Object; 
+ (warm) java/util/HashMap.put(Ljava/lang/Object;Ljava/lang/Object;)
                 Ljava/lang/Object; @ 0x02BA0270-0x02BA03F7   
                (2) Compiling java/lang/String.charAt(I)C 
+ (warm) java/lang/String.charAt(I)C @ 0x02BA0430-0x02BA04AC   
       (2) Compiling java/util/Locale.toLowerCase(Ljava/lang/String;)
                Ljava/lang/String; 
+ (warm) java/util/Locale.toLowerCase(Ljava/lang/String;)Ljava/lang/String; 
                                                    @ 0x02BA04D0-0x02BA064C

When you have monitored how much native heap you are using, you can increase or decrease the maximum native heap available by altering the size of the Java™ heap. This relationship between the heaps occurs because the process address space not used by the Java heap is available for the native heap usage.

You must increase the native heap if the process is generating errors relating to a failure to allocate native resources or exhaustion of process address space. These errors can take the form of a JVM internal error message or a detail message associated with an OutOfMemoryError. The message associated with the relevant errors will make it clear that the problem is native heap exhaustion.