[OpenJDK 2D-Dev] [14] RFR JDK-8235147: Release HDC from passiveDCList sooner

[Sergey Bylokhov]

Looks fine.

On 2/6/20 1:39 pm, Alexey Ivanov wrote:
> Hello once again,
> 
> After trying a few things suggested by Sergey, I found serious issues in the new approaches although the code looked a bit cleaner. Resolving those issues requires substantial changes to the way we handle the active and passive DC lists.
> 
> Thus, it's safer to postpone further refactoring to a later time.
> 
> So we're back to the original proposal.
> 
> I'm quoting it for your convenience below:
> 
> JBS: https://bugs.openjdk.java.net/browse/JDK-8235147
> Webrev: http://cr.openjdk.java.net/~aivanov/8235147/webrev.00/
> 
> 
> When a DC becomes unused, it is moved from activeDCList to passiveDCList to be released later. It will stay in the passiveDCList until a new DC is requested for the same window or the window is destroyed.
> 
> The DCs in passiveDCList will never be used again, so we can release them as soon as another request for a DC comes in.
> 
> The test case, ManyFramesTest.java, attached to the bug creates and displays 10 frames. Then it hides the 9 frames. At this point, passiveDCList contains 9 entries. These DCs will not be released until the corresponding frame is shown and painted again or the frame is destroyed.
> 
> 
> The fix releases all DCs currently in passiveDCList when another DC is requested.
> With the fix, when running ManyFramesTest.java test case, the number of entries in passiveDCList does not grow, the list contains at most 1 entry.
> 
> 
> On 12/12/2019 20:46, Alexey Ivanov wrote:
>> Hi Sergey,
>>
>> <SNIP>
>>
>>
>> It does not work good. I found serious issues in either approach I've tried so far.
>>
>> Thus, we're down to the original proposal:
>>
>> JBS: https://bugs.openjdk.java.net/browse/JDK-8235147
>> Webrev: http://cr.openjdk.java.net/~aivanov/8235147/webrev.00/
>>


-- 
Best regards, Sergey.