RFR 8206424: Use locking for cleaning ProtectionDomainTable

[coleen.phillimore at oracle.com]

On 8/21/18 10:23 PM, David Holmes wrote:
> Hi Patricio,
>
> Actual changes seem fine - thanks.
>
> I have a meta question about what we are doing and why. IIUC we're 
> trying to offload work from the VMThread at a safepoint, to the 
> ServiceThread not-at-a-safepoint - is that correct? Have we looked at 
> the amount of work this can generate in the service thread and the 
> potentially latency introduced for the cleanup actions? Also if the 
> service thread gets too much work to do it will delay the next 
> safepoint (as I'm not expecting these cleanup tasks to themselves 
> encounter safepoint checks).

This is correct.  These table are small and the locks that clean up 
these tables check for safepoints like good citizens.

Thanks,
Coleen
>
> And having just asked a question I have to apologise that I'll be on 
> vacation by the time you can respond to it. :) But the discussion can 
> keep till later.
>
> Thanks,
> David
>
> On 22/08/2018 7:31 AM, Patricio Chilano wrote:
>> Hi Ioi and Coleen,
>>
>> Thanks for reviewing this change! I moved the test to 
>> test/hotspot/jtreg/runtime/Dictionary and fixed the copyright. Here 
>> is the new webrev:
>>
>> Webrev URL: http://cr.openjdk.java.net/~pchilanomate/8206424.02/webrev
>>
>> Thanks,
>> Patricio
>>
>> On 8/21/18 5:11 PM, coleen.phillimore at oracle.com wrote:
>>>
>>> Patricio,
>>>
>>> This looks really good.  I agree with Ioi's comment.  Maybe the test 
>>> could go into test/hotspot/jtreg/runtime/Dictionary (there are 
>>> similar tests there?)
>>>
>>> Also the copyright should just have 2018 followed by a comma (even 
>>> though grammatically incorrect).
>>>
>>> thanks,
>>> Coleen
>> On 8/21/18 3:27 PM, Ioi Lam wrote:
>>> Hi Patricio,
>>>
>>> I think the test should be under a different directory since it is 
>>> not specific to AppCDS
>>>
>>> Thanks
>>> Ioi
>>>
>>>> On Aug 21, 2018, at 11:47 AM, Patricio Chilano 
>>>> <patricio.chilano.mateo at oracle.com> wrote:
>>>>
>>>> Hi all,
>>>> Could you review this fix that moves the cleanup of dead entries in 
>>>> the protection domain table from the VMThread to the ServiceThread.
>>>> The goal is the same as JDK-8206423. The task of cleaning up dead 
>>>> entries in the protection domain table was moved to the ServiceThread.
>>>> The fix was tested with Mach5 on tiers 1, 2, 3 on all platforms. A 
>>>> new test 
>>>> (test/hotspot/jtreg/runtime/appcds/CleanProtectionDomain.java) was 
>>>> added to test the creation and removal of entries in the Protection 
>>>> Domain table.
>>>> Bug URL: https://bugs.openjdk.java.net/browse/JDK-820642 
>>>> <https://bugs.openjdk.java.net/browse/JDK-8206423>4
>>>> Webrev URL: 
>>>> http://cr.openjdk.java.net/~pchilanomate/8206424.01/webrev/index.html
>>>> Thanks,
>>>> Patricio
>>>>
>>