Question for MinMetaspaceFreeRatio and MaxMetaspaceFreeRatio

[Roy Zhang]

Dear JVM experts,

Regarding to https://gist.github.com/erikdw/e730a1249887bb4462f226658351cfa4,
we can set -XX:MinMetaspaceFreeRatio=0 & -XX:MaxMetaspaceFreeRatio=100 to
disable dynamic resize metaSpace (changing high-water mark) which could
trigger full gc. But when i set the following metaspace related java
opts(MetaspaceSize and MaxMetaspacesize is 2g), reserved MetaspaceSize is
still 1G which is same as the default behavior(didn't set any metaSpace
related java opts, MetaspaceSize is ~20M).
Could u please kindly provide help? Thx in advance!

jcmd 15958 GC.heap_info
15958:
 garbage-first heap   total 10485760K, used 2490178K [0x0000000540000000,
0x0000000540405000, 0x00000007c0000000)
  region size 4096K, 552 young (2260992K), 0 survivors (0K)
* Metaspace       used 25746K, capacity 26634K, committed 26752K, reserved
1073152K*
  class space    used 2227K, capacity 2358K, committed 2432K, reserved
1048576K

*Metaspace java opts:*
-XX:MetaspaceSize=2g
-XX:MaxMetaspaceSize=2g
-XX:MinMetaspaceFreeRatio=0
-XX:MaxMetaspaceFreeRatio=100

*JVM version*:
openjdk version "1.8.0_201"
OpenJDK Runtime Environment (build 1.8.0_201-b09)
OpenJDK 64-Bit Server VM (build 25.201-b09, mixed mode)

*Linux version:*
4.14.123-111.109.amzn2.x86_64

Thanks,
Roy
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mail.openjdk.java.net/pipermail/hotspot-gc-use/attachments/20191017/8e041744/attachment.html>