Promptly freeing the per-thread cached direct buffers when a thread exits

[Peter Levart]

On 04/09/18 10:33, David Holmes wrote:
>> After thread exits, ThreadLocal values associated with it are no 
>> longer reachable from its Thread object.
>>
>> The problem Tony faces is that by the time this happens, direct 
>> ByteBuffer's that were cached using such ThreadLocal value, are 
>> already moved to old GC generation, waiting for full GC to release 
>> them together with direct memory they are holding.
>
> Right. So the suggestion was to call ThreadLocal.remove() instead (as 
> well as?) so that you could define a custom ThreadLocal class for the 
> buffers that override remove() to actually release the buffer directly.
>
> David 

Ah, of course. But the concern is that custom code at thread-exit is not 
desirable. Alan is propagating private internal API. Here's a prototype:

http://cr.openjdk.java.net/~plevart/jdk-dev/DBBCache_Cleanup/webrev.00/

Would something like this be acceptable?

Regards, Peter