RFR(xxs): 8209495: NMethodSweeper::sweep_code_cache cause severe delays

[Robbin Ehn]

Thanks Erik!

/Robbin

On 31/10/2018 16:12, Erik Österlund wrote:
> Hi Robbin,
> 
> Looks good.
> 
> Thanks,
> /Erik
> 
> On 2018-10-31 15:38, Robbin Ehn wrote:
>> Hi please review,
>>
>> Issue:
>> https://bugs.openjdk.java.net/browse/JDK-8209495
>>
>> Code:
>> diff -r 875999ffe38d src/hotspot/share/runtime/sweeper.cpp
>> --- a/src/hotspot/share/runtime/sweeper.cpp    Wed Oct 31 14:07:15 2018 +0100
>> +++ b/src/hotspot/share/runtime/sweeper.cpp    Wed Oct 31 15:28:39 2018 +0100
>> @@ -390,1 +390,2 @@
>> -  if (SafepointSynchronize::is_synchronizing()) {
>> +  JavaThread* thread = JavaThread::current();
>> +  if (SafepointMechanism::poll(thread)) {
>> @@ -396,1 +396,0 @@
>> -    JavaThread* thread = JavaThread::current();
>>
>>
>> Since we only do the ThreadBlockInVM if there is a safepoint,
>> this have a bad effect on handshakes.
>>
>> RunThese30M works with much lower timeout, tenths of millis.
>>
>> Thanks, Robbin
>