Reputation: 5333
Why jvm increase all the time without shrink even if has -XX:MaxHeapFreeRatio jvm argument
from jmap result, we can see, free heap size(up to 90%) exceed MaxHeapFreeRatio(40%), but jvm still not shrink.
this is jvm info: java.vm.name = OpenJDK 64-Bit Server VM java.vm.version = 25.352-b1 java.runtime.version = 1.8.0_352-b1
VM Flags: Non-default VM flags: -XX:CICompilerCount=2 -XX:CompressedClassSpaceSize=1065353216 -XX:ConcGCThreads=1 -XX:G1HeapRegionSize=1048576 -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=null -XX:InitialHeapSize=2577399808 -XX:InitialRAMPercentage=null -XX:MarkStackSize=4194304 -XX:MaxHeapFreeRatio=40 -XX:MaxHeapSize=6014631936 -XX:MaxMetaspaceSize=1073741824 -XX:MaxNewSize=3608150016 -XX:MaxRAMPercentage=null -XX:MetaspaceSize=536870912 -XX:MinHeapDeltaBytes=1048576 -XX:MinHeapFreeRatio=20 -XX:MinRAMPercentage=null -XX:+PrintGC -XX:+PrintGCDateStamps -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -XX:SurvivorRatio=6 -XX:+UseAdaptiveSizePolicy -XX:+UseCompressedClassPointers -XX:+UseCompressedOops -XX:+UseContainerSupport -XX:+UseG1GC -XX:+UseUTF8UTF16Intrinsics
Command line: -Duser.timezone=GMT+8 -Dfile.encoding=utf-8 -XX:+UseContainerSupport -XX:InitialRAMPercentage=30.0 -XX:MinRAMPercentage=70.0 -XX:MaxRAMPercentage=70.0 -XX:+UseAdaptiveSizePolicy -XX:MaxHeapFreeRatio=40 -XX:MinHeapFreeRatio=20 -XX:+UseG1GC -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=/logs/my-heap-dump.hprof -XX:SurvivorRatio=6 -XX:MetaspaceSize=512m -XX:MaxMetaspaceSize=1024m -Xloggc:/logs/gc.log -XX:+PrintGCDetails -XX:+PrintGCDateStamps -Djava.security.egd=file:/dev/./urandom
-XX:+UseAdaptiveSizePolicy -XX:MaxHeapFreeRatio=40 -XX:MinHeapFreeRatio=20
with these arguments, I think jvm should shrink dynamicly according to heap idea memory.
Upvotes: 0
Views: 149
Answers (1)
Reputation: 43052
MaxHeapFreeRatio is not honored immediately to avoid rapid allocation and deallocation of the heap in bursty workloads, you can add ShrinkHeapInSteps to apply the limit more aggressively.
If that doesn't work you should look at the adaptive sizing policy decisions in the gc logs.
Upvotes: 0