RFR (L): 8073500: Prevent certain commercial flags from being changed at runtime

[Gerard Ziemski]

hi Coleen,

Thank you for the review.

> On May 5, 2016, at 4:01 PM, Coleen Phillimore <coleen.phillimore at oracle.com> wrote:
> 
> 
> Hi,   This looks good.  I only have minor comments for which I don't need to see another webrev.
> 
> http://cr.openjdk.java.net/~gziemski/8073500_rev1/src/share/vm/runtime/globals.cpp.udiff.html
> 
> *+ if (writeable) {*
> 
> 
> This should be if (writeable != NULL).

Fixed.


> 
> http://cr.openjdk.java.net/~gziemski/8073500_rev1/src/share/vm/runtime/commandLineFlagWriteableList.hpp.html
> 
>  48   CommandLineFlagWriteable(const char* name, WriteableType type) { _name=name; _type=type; _writeable=true; _startup_done=false; }
> 
> 
> C++ initializers are preferred here.
> 
>  48   CommandLineFlagWriteable(const char* name, WriteableType type) : _name(name), _type(type), _writeable(true), _startup_done(false) { }

Fixed.


> 
> 
> http://cr.openjdk.java.net/~gziemski/8073500_rev1/src/share/vm/runtime/commandLineFlagWriteableList.cpp.html
> 
> Does this really need all of these #includes?

I removed:

#include “gc/cms/concurrentMarkSweepGeneration.inline.hpp”
#include “gc/g1/heapRegionBounds.inline.hpp”
#include “gc/shared/plab.hpp

The rest are needed I believe.


> 
> Copyright date should be only 2016.

Fixed.


Tank you.


> 
> Thanks,
> Coleen
> 
> 
> On 5/2/16 12:29 PM, Gerard Ziemski wrote:
>> hi all,
>> 
>> Please review this fix (large code change, but relatively straightforward implementation wise), which implements a mechanism for enforcing when and how a runtime flag may be modified. There are 3 new types, which can be assigned:
>> 
>> - writeable(Always) is optional and default value, which places no limits on when or how often a flag may be changed
>> 
>> - writeable(Once) denotes that a flag may be >> changed << only once. We allow case such as “java -XX:+UnlockCommercialFeatures ... -XX:+UnlockCommercialFeatures ...” to support existing usage. This is OK, because here the flag only changes its value >> once << , ie. from false to true.
>> 
>> - writeable(CommandLineOnly) denotes that a flag may only be changed from the command line (tools like jcmd may not change such a flag during the runtime)
>> 
>> The implementation is based on the same mechanism as that in JEP-245 (https://bugs.openjdk.java.net/browse/JDK-8059557)
>> 
>> 
>> bug:    https://bugs.openjdk.java.net/browse/JDK-8073500
>> webrev: http://cr.openjdk.java.net/~gziemski/8073500_rev1/
>> 
>> Tested with “JPRT hotspot” and “RBT hs-nightly-runtime”
>> 
>> 
>> cheers
>