RFR: 8329223: Parallel: Parallel GC resizes heap even if -Xms = -Xmx [v7]

[Albert Mingkun Yang]

On Mon, 22 Apr 2024 14:15:50 GMT, Zhengyu Gu <zgu at openjdk.org> wrote:

>> It's mostly to be consistent with `initial_old_size = MaxOldSize;` a few lines above; if the cmdline `OldSize` is inconsistent with other flags, change `OldSize` to fit others.
>> 
>> Technically, when there's inconsistency in cmdline flags, change any of them is equally correct, IMO. In the long run, maybe it's possible to remove the `OldSize` flag, since one can achieve old-size via `InitialHeapSize` and `NewSize`.
>
> Hmmm, setting `initial_old_size = MaxOldSize` fails `gtest` again:
> 
> [----------] 4 tests from CollectorPolicy
> [ RUN      ] CollectorPolicy.young_min_ergo_vm
> [       OK ] CollectorPolicy.young_min_ergo_vm (0 ms)
> [ RUN      ] CollectorPolicy.young_scaled_initial_ergo_vm
> [       OK ] CollectorPolicy.young_scaled_initial_ergo_vm (0 ms)
> [ RUN      ] CollectorPolicy.young_cmd_other_vm
> [       OK ] CollectorPolicy.young_cmd_other_vm (79 ms)
> [ RUN      ] CollectorPolicy.old_cmd_other_vm
> [0.050s][warning][gc,ergo] Inconsistency between initial old size and minimum old size
> [0.050s][warning][gc,ergo] Inconsistency between generation sizes and heap size, resizing the generations to fit the heap.
> /Users/zhengyu.gu/ws/jdk/test/hotspot/gtest/gc/shared/test_collectorPolicy.cpp:261: Failure
> Death test: child_CollectorPolicy_old_cmd_()
>     Result: died but not with expected exit code:
>             Terminated by signal 6
> Actual msg:
> [  DEATH   ] 
> [  DEATH   ] [ FATAL ] /Users/zhengyu.gu/ws/googletest-1.14.0/googletest/include/gtest/internal/gtest-port.h:1710:: pthread_mutex_destroy(&mutex_)failed with error 16
> [  DEATH   ] 
> 
> [  FAILED  ] CollectorPolicy.old_cmd_other_vm (78 ms)
> [----------] 4 tests from CollectorPolicy (158 ms total)

Maybe my prev msg was misleading... Reprint the code-snippet:


    if (initial_old_size > MaxOldSize) {
      log_warning(gc, ergo)(...);
      initial_old_size = MaxOldSize;
    } else if (initial_old_size < MinOldSize) {
      log_waring(gc, ergo)(...);
      initial_old_size = MinOldSize;
    }

so that the two assignment to `initial_old_size` matches up, accounting for over/under flow.

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/18539#discussion_r1574851093