[crac] RFR: Support updating MANAGEABLE JVM options during restore [v2]

[Anton Kozlov]

On Wed, 3 May 2023 11:25:11 GMT, Radim Vansa <duke at openjdk.org> wrote:

>> src/hotspot/share/runtime/globals.hpp line 2129:
>> 
>>> 2127:       "Throw CheckpointException if uncheckpointable resource handle found")\
>>> 2128:                                                                             \
>>> 2129:   product(bool, CRTrace, true, MANAGEABLE, "Minimal C/R tracing")           \
>> 
>> RESTORE_SETTABLE was meant here? Please don't mix in MANAGEABLE flags into this PR if that was inteded.
>
> Looking for usages (actually only one) of the flag, it qualifies to be set at any time.

// MANAGEABLE flags are writeable external product flags.
//    They are dynamically writeable through the JDK management interface
//    (com.sun.management.HotSpotDiagnosticMXBean API) and also through JConsole.
//    These flags are external exported interface (see CCC).  The list of
//    manageable flags can be queried programmatically through the management
//    interface.


Manageable does not mean "can be set at any time". All product flags are part of the VM interface, but MANAGEABLE is stricter.

Actually, the flag should be eliminated and replaced with Unified Logging, so let's just set RESETORE_SETTABLE for this.

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PR Review Comment: https://git.openjdk.org/crac/pull/61#discussion_r1190047188