On Thu, 26 Sep 2024 12:29:14 GMT, Robert Toyonaga <d...@openjdk.org> wrote:
>> ### Summary
>> This PR just replaces `ThreadCritical` with a lock specific to NMT.
>> `ThreadCritical` is a big lock and is unnecessary for the purposes of NMT.
>> I've implemented the new lock with a semaphore so that it can be used early
>> before VM init. There is also the possibility of adding assertions in
>> places we expect NMT to have synchronization. I haven't added assertions yet
>> in many places because some code paths such as the (NMT tests) don't lock
>> yet. I think it makes sense to close any gaps in locking in another PR in
>> which I can also add more assertions.
>>
>> Testing:
>> - hotspot_nmt
>> - gtest:VirtualSpace
>> - tier1
>
> Robert Toyonaga has updated the pull request incrementally with one
> additional commit since the last revision:
>
> Rename lock and mutex locker. Add back ThreadCritical when protecting
> mtChunk.
Okay I am happy with this now. Thanks.
If I heard correctly Thomas is on vacation this month so you may need to
proceed with a different second review and follow up when he gets back if there
are any problems. I will be on vacation after Friday for 10 days.
src/hotspot/share/utilities/vmError.cpp line 723:
> 721: // Avoid reentrancy due to mallocs in detailed mode.
> 722: MemTracker::reduce_tracking_to_summary();
> 723: // Manually unlock if already holding lock when upon entering error
> reporting.
Suggestion:
// Manually unlock if already holding lock upon entering error reporting.
-------------
Marked as reviewed by dholmes (Reviewer).
PR Review: https://git.openjdk.org/jdk/pull/20852#pullrequestreview-2341807048
PR Review Comment: https://git.openjdk.org/jdk/pull/20852#discussion_r1783770844
