RFR: 8351655: Optimize ObjectMonitor::unlink_after_acquire() [v2]

[Fredrik Bredberg]

On Thu, 20 Mar 2025 03:48:32 GMT, David Holmes <dholmes at openjdk.org> wrote:

>> Fredrik Bredberg has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Update after review
>
> src/hotspot/share/runtime/objectMonitor.cpp line 1256:
> 
>> 1254: // pointers and the entry_list_tail pointer. Within the entry_list the
>> 1255: // next pointers always form a consistent singly linked list. The
>> 1256: // entry_list can be in either of these forms:
> 
> Suggestion:
> 
> // entry_list can be in any of these forms:
> 
> "either" implies two choices

Fixed

> src/hotspot/share/runtime/objectMonitor.cpp line 1273:
> 
>> 1271:   while (w != nullptr) {
>> 1272:     assert(w->TState == ObjectWaiter::TS_ENTER, "invariant");
>> 1273:     assert(w->prev() == nullptr || w->prev() == prev, "should be");
> 
> Suggestion s/should be/invariant/ for all these assertions

Fixed

> src/hotspot/share/runtime/objectMonitor.cpp line 1297:
> 
>> 1295:     // and we don't have the tail pointer, something is broken.
>> 1296:     assert(_entry_list_tail != nullptr, "should be");
>> 1297: #ifdef ASSERT
> 
> I would move this `#ifdef ASSERT` to before the comment to make it clear the comment pertains to debug code.

Fixed

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

PR Review Comment: https://git.openjdk.org/jdk/pull/24078#discussion_r2005831461
PR Review Comment: https://git.openjdk.org/jdk/pull/24078#discussion_r2005832339
PR Review Comment: https://git.openjdk.org/jdk/pull/24078#discussion_r2005831909