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

[Radim Vansa]

On Wed, 3 May 2023 11:17:17 GMT, Anton Kozlov <akozlov at openjdk.org> wrote:

>> Radim Vansa has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Use RESTORE_SETTABLE on JVM flags
>>   
>>   * Fail early when using non settable flags
>>   * CracBuilder fix: don't use classpath during restore
>
> src/hotspot/share/runtime/globals.hpp line 2094:
> 
>> 2092:                 "Trace optimized upcall stub generation")                   \
>> 2093:                                                                             \
>> 2094:   product(ccstr, CRaCCheckpointTo, NULL, MANAGEABLE,                        \
> 
> I see reasons for CRaCCheckpointTo to be MANAGEABLE, but at the moment the flag is assumed to be set in the command line by the implementation, e.g. os::Linux::{vm_create_start,prepare_checkpoint} are called depending on the flag value, and that can happen only during VM initialization.
> 
> A set of changes are required before the option can become MANAGEABLE.
> 
> The test should also updated once the option is reverted.

Well spotted, I was thinking about changing the path but these two places need to be called in order to prepare for a checkpoint.

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PR Review Comment: https://git.openjdk.org/crac/pull/61#discussion_r1183629613