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jvm: drop UseCompressedOops JVM option #7702

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jvm: drop UseCompressedOops JVM option #7702

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kofemann
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Motivation:
Starting java7, the UseCompressedOops is dynamically controed by heap size.

$ java -Xmx32g -XX:+PrintFlagsFinal 2>/dev/null | grep UseCompressedOops
     bool UseCompressedOops                        = false                          {product lp64_product} {default}

$ java -Xmx28g -XX:+PrintFlagsFinal 2>/dev/null | grep UseCompressedOops
     bool UseCompressedOops                        = true                           {product lp64_product} {ergonomic}

The mismatch between UseCompressedOops endup with error:

OpenJDK 64-Bit Server VM warning: Max heap size too large for Compressed Oops
***** WARNING! INCORRECT SYSTEM CONFIGURATION DETECTED! *****
The system limit on number of memory mappings per process might be too low for the given
[gc] max Java heap size (40960M). Please adjust /proc/sys/vm/max_map_count to allow for at
[gc] least 73728 mappings (current limit is 65530). Continuing execution with the current

Modification:
drop UseCompressedOops JVM option from defaults.

Result:
correct behavior on JVMs with large heap

Acked-by: Lea Morschel
Target: master
Require-book: no
Require-notes: yes
(cherry picked from commit 59ea69f)

Motivation:
Starting java7, the UseCompressedOops is dynamically controed by heap
size.

```
$ java -Xmx32g -XX:+PrintFlagsFinal 2>/dev/null | grep UseCompressedOops
     bool UseCompressedOops                        = false                          {product lp64_product} {default}

$ java -Xmx28g -XX:+PrintFlagsFinal 2>/dev/null | grep UseCompressedOops
     bool UseCompressedOops                        = true                           {product lp64_product} {ergonomic}
```

The mismatch between UseCompressedOops endup with error:

```
OpenJDK 64-Bit Server VM warning: Max heap size too large for Compressed Oops
***** WARNING! INCORRECT SYSTEM CONFIGURATION DETECTED! *****
The system limit on number of memory mappings per process might be too low for the given
[gc] max Java heap size (40960M). Please adjust /proc/sys/vm/max_map_count to allow for at
[gc] least 73728 mappings (current limit is 65530). Continuing execution with the current
```

Modification:
drop UseCompressedOops JVM option from defaults.

Result:
correct behavior on JVMs with large heap

Acked-by: Lea Morschel
Target: master
Require-book: no
Require-notes: yes
(cherry picked from commit 59ea69f)
Signed-off-by: Tigran Mkrtchyan <[email protected]>
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