RFR: 8328944: NMT reports "unknown" memory [v2]

[Gerard Ziemski]

On Wed, 20 Nov 2024 15:29:45 GMT, Stefan Karlsson <stefank at openjdk.org> wrote:

>> Gerard Ziemski has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains six additional commits since the last revision:
>> 
>>  - avoid using mtNone
>>  - Merge remote-tracking branch 'upstream/master' into JDK-8328944
>>  - revert, we will re-do with a smaller change
>>  - remove more mtNone
>>  - remove API that allows to change the mem_tag for virtual memory, feedback
>>  - do not allow default parameter for mtNone
>
> src/hotspot/os/linux/os_linux.cpp line 4587:
> 
>> 4585:   char* hint = (char*)(os::Linux::initial_thread_stack_bottom() -
>> 4586:                        (StackOverflow::stack_guard_zone_size() + page_size));
>> 4587:   char* codebuf = os::attempt_reserve_memory_at(hint, page_size, false, mtInternal);
> 
> Could this be mtThread instead?

Makes sense, fixed.

> src/hotspot/os/linux/os_linux.cpp line 4595:
> 
>> 4593:     // map our codebuf, try again at an address one megabyte lower.
>> 4594:     hint -= 1 * M;
>> 4595:     codebuf = os::attempt_reserve_memory_at(hint, page_size, false, mtInternal);
> 
> Could this be mtThread instead?

Makes sense, fixed.

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

PR Review Comment: https://git.openjdk.org/jdk/pull/21843#discussion_r1852634508
PR Review Comment: https://git.openjdk.org/jdk/pull/21843#discussion_r1852634648