RFR(S)[16]: 8246477: add whitebox support for deflating idle monitors

[Daniel D. Daugherty]

Hi David,

On 6/22/20 3:47 AM, David Holmes wrote:
> Hi Dan,
>
> This all seems fine to me.

Thanks! And thanks for the review of yet-another-monitor-subsystem fix!!


>
> A couple of nits:
>
> src/hotspot/share/runtime/synchronizer.cpp
>
> +     if (ret_code == false) {
>
> => if (!ret_code) {

Nice catch. Will fix that.


> ---
>
> test/hotspot/jtreg/runtime/whitebox/TestWBDeflateIdleMonitors.java
>
>  27  * @test TestWBDeflateIdleMonitors
>
> @test is a marker. We don't/shouldn't write anything after it.

Will fix. I got that from test/hotspot/jtreg/gc/whitebox/TestWBGC.java
which I copied and adapted for this new test.


>
> 29  * @summary Test verify that WB method deflateIdleMonitors works 
> correctly.
>
> "Test verify" is not grammatically correct.

Perhaps: Test to verify that WB method deflateIdleMonitors works correctly.

I'm sorry to say that I also got that grammatical error from
test/hotspot/jtreg/gc/whitebox/TestWBGC.java which I copied and adapted
for this new test.

I'll file a follow-up bug for test/hotspot/jtreg/gc/whitebox/TestWBGC.java
so that we don't lose those fixes.

Dan


>
> ---
>
> Thanks,
> David
>
> On 20/06/2020 2:58 am, Daniel D. Daugherty wrote:
>> Ping!
>>
>> And a testing update:
>>
>> Mach5 Tier[1-8] testing:
>>
>>    Tier[1-3] - done, 5 unrelated, known failures
>>    Tier4     - done - 1 unrelated, known failure
>>    Tier5     - done - no failures
>>    Tier6     - done, 1 unrelated, known failure
>>    Tier7     - almost done, 1 unrelated, known failure
>>    Tier8     - 56% done, 3 unrelated, known failures (so far)
>>
>> The Mach5 testing is taking longer than usual due to resource 
>> limitations.
>> So far all failures are known to be in the baseline. There have been no
>> test failures related to not deflating an idle monitor in a timely 
>> fashion
>> (so far).
>>
>> Thanks, in advance, for comments, questions or suggestions.
>>
>> Dan
>>
>> On 6/17/20 12:30 PM, Daniel D. Daugherty wrote:
>>> Greetings,
>>>
>>> I have a fix for cleaning up testing support for deflating idle 
>>> monitors.
>>>
>>> JDK-8246477 add whitebox support for deflating idle monitors
>>> https://bugs.openjdk.java.net/browse/JDK-8246477
>>>
>>> This project is based on jdk-16+1 and is targeted to JDK16.
>>>
>>> Here's the webrev URL:
>>>
>>> http://cr.openjdk.java.net/~dcubed/8246477-webrev/0-for-jdk16/
>>>
>>> Summary of the changes:
>>>
>>> - Add whitebox support for deflating idle monitors including
>>>   ObjectSynchronizer::request_deflate_idle_monitors(); includes
>>>   a new whitebox test.
>>> - Drop ObjectSynchronizer::_is_special_deflation_requested flag,
>>>   functions and uses.
>>> - Switch to ObjectSynchronizer::request_deflate_idle_monitors() as 
>>> needed.
>>> - bug fix: _last_async_deflation_time_ns should be set at the end of
>>>   async deflation.
>>>
>>> Because this fix is removing support for special deflation requests,
>>> I'm doing Mach5 Tier[1-8] testing:
>>>
>>>   Tier[1-3] - almost done, 5 unrelated, known failures
>>>   Tier4     - done - 1 unrelated, known failure
>>>   Tier5     - done - no failures
>>>   Tier6     - almost done, 1 unrelated, known failure
>>>   Tier7     - almost done, 1 unrelated, known failure
>>>   Tier8     - > half done, 3 unrelated, known failures (so far)
>>>
>>> The Mach5 testing is taking longer than usual due to resource 
>>> limitations.
>>> So far all failures are known to be in the baseline. There have been no
>>> test failures related to not deflating an idle monitor in a timely 
>>> fashion
>>> (so far).
>>>
>>> Thanks, in advance, for comments, questions or suggestions.
>>>
>>> Dan
>>