RFR: 8344883: Do not use mtNone if we know the tag type [v2]

[Gerard Ziemski]

On Fri, 28 Mar 2025 07:59:08 GMT, Stefan Karlsson <stefank at openjdk.org> wrote:

>> Gerard Ziemski has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   work
>
> src/hotspot/share/runtime/safepointMechanism.cpp line 60:
> 
>> 58:     const size_t page_size = os::vm_page_size();
>> 59:     const size_t allocation_size = 2 * page_size;
>> 60:     char* polling_page = os::reserve_memory(allocation_size, mtSafepoint, !ExecMem);
> 
> Suggestion:
> 
>     char* polling_page = os::reserve_memory(allocation_size, mtSafepoint);

I think here we need to keep `!ExecMem` since it is a parameter.

> src/hotspot/share/utilities/debug.cpp line 715:
> 
>> 713: #ifdef CAN_SHOW_REGISTERS_ON_ASSERT
>> 714: void initialize_assert_poison() {
>> 715:   char* page = os::reserve_memory(os::vm_page_size(), mtInternal, !ExecMem);
> 
> Suggestion:
> 
>   char* page = os::reserve_memory(os::vm_page_size(), mtInternal);

Again, `ExecMem` is a parameter.

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PR Review Comment: https://git.openjdk.org/jdk/pull/24282#discussion_r2021769950
PR Review Comment: https://git.openjdk.org/jdk/pull/24282#discussion_r2021770850