Request for reviews (S): 7190310: Inlining WeakReference.get(), and hoisting $referent may lead to non-terminating loops

[Vladimir Kozlov]

Christian Thalinger wrote:
> On Aug 9, 2012, at 7:15 PM, Vladimir Kozlov <vladimir.kozlov at oracle.com> wrote:
> 
>> Thanks, David
>>
>> pre_barrier() methods don't generate code for other GCs. But I forgot to put UseG1GC guard around "new G1UnsafeGetObjSATBBarrierStub" in c1_LIRGenerator.cpp.
> 
> Did you update the webrev?  -- Chris

Not yet. I want to rewrite that code (which use G1UnsafeGetObjSATBBarrierStub).

Vladimir

> 
>> Thanks,
>> Vladimir
>>
>> On 8/9/12 6:52 PM, David Holmes wrote:
>>> On 10/08/2012 11:34 AM, Vladimir Kozlov wrote:
>>>> http://cr.openjdk.java.net/~kvn/7190310/webrev
>>>>
>>>> 7190310: Inlining WeakReference.get(), and hoisting $referent may lead
>>>> to non-terminating loops
>>>>
>>>> Add acquire membar after load from Reference.referent field to prevent
>>>> commoning of loads across safepoint since GC can change its value.
>>> Wow that was quick! :)
>>>
>>> My only comment (not being a compiler expert) is that it would appear that we are now inserting read barriers with all
>>> GC's not just G1. What kind of impact will that have on performance under the other GC's?
>>>
>>> Thanks,
>>> David
>>>
>>>> Thanks,
>>>> Vladimir