RFR: 8354547: REDO: Force clients to explicitly pass mem_tag value, even if it is mtNone [v2]

[Stefan Karlsson]

On Tue, 15 Apr 2025 14:52:03 GMT, Gerard Ziemski <gziemski at openjdk.org> wrote:

>> Redo for a follow-up to https://github.com/openjdk/jdk/pull/21843. Here we are focusing on removing the mem tag paremeter with default value of mtNone, to force everyone to provide mem tag, if known.
>> 
>> I tried to fill in tag, when I was pretty certain that I had the right type.
>> 
>> At least one more follow-up will be needed after this, to change the remaining mtNone to valid values.
>> 
>> Testing: tier1-5 in progress
>
> Gerard Ziemski has updated the pull request incrementally with one additional commit since the last revision:
> 
>   fix build break

In the previous iteration of this patch we removed the unnecessary `false`/`!ExecMem` arguments, but that last two changes keep them. After fixing these, please make sure to test that this builds.

src/hotspot/share/cds/metaspaceShared.cpp line 1348:

> 1346:           assert(prot_zone_size >= os::vm_allocation_granularity(), "must be"); // not just page size!
> 1347:           char* p = os::attempt_reserve_memory_at(mapped_base_address, prot_zone_size,
> 1348:                                                   mtClassShared, false);

Suggestion:

                                                  mtClassShared);

test/hotspot/gtest/gc/z/test_zVirtualMemoryManager.cpp line 131:

> 129:     // Reserve the memory that is acting as a blocking reservation.
> 130:     {
> 131:       char* const result = os::attempt_reserve_memory_at((char*)untype(blocked), ZGranuleSize, mtTest, !ExecMem);

Suggestion:

      char* const result = os::attempt_reserve_memory_at((char*)untype(blocked), ZGranuleSize, mtTest);

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

Changes requested by stefank (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/24634#pullrequestreview-2768728457
PR Review Comment: https://git.openjdk.org/jdk/pull/24634#discussion_r2044839241
PR Review Comment: https://git.openjdk.org/jdk/pull/24634#discussion_r2044818399