Object to ObjectMonitor mapping using a HashTable to avoid displaced headers

[Andrew Haley]

On 1/31/24 17:19, Kennke, Roman wrote:
> As mentioned we have been working on a solution which uses an external hash table to map objects to their respective ObjectMonitor.

That's great news.

Historical note: we did that in GCJ, long before OpenJDK was a thing.
When OpenJDK began I had to learn about HotSpot. I remember being in
the audience in a talk about the layout of an object. When I learned
about the lock word, I was very surprised. Why would you want to waste
a whole word of every object? ;-)

-- 
Andrew Haley  (he/him)
Java Platform Lead Engineer
Red Hat UK Ltd. <https://www.redhat.com>
https://keybase.io/andrewhaley
EAC8 43EB D3EF DB98 CC77 2FAD A5CD 6035 332F A671