[9] RFR(S): 8005873: JRuby test_respond_to.rb asserts with: MT-unsafe modification of inline cache

[Vladimir Ivanov]

On 6/2/14 9:23 PM, Christian Thalinger wrote:
>
> On Jun 2, 2014, at 6:29 AM, Vladimir Ivanov <vladimir.x.ivanov at oracle.com> wrote:
>
>> Tobias, I'll take care of it.
>
> Are you also taking care of the backports?
Yes. I'll backport into 8u myself and for 7 I'll ask help from Sustaining.

Best regards,
Vladimir Ivanov
>
>>
>> Best regards,
>> Vladimir Ivanov
>>
>> On 6/2/14 10:04 AM, Tobias Hartmann wrote:
>>>
>>> On 28.05.2014 12:48, Vladimir Ivanov wrote:
>>>> Looks good.
>>>>
>>>> It should be safe to sync on MTF instance since it's not accessible
>>>> outside (MTF and MT.form() are package-private).
>>>>
>>>> Best regards,
>>>> Vladimir Ivanov
>>>
>>> Thank you, Vladimir.
>>>
>>> Could someone please push the patch?
>>>
>>> Thanks,
>>> Tobias
>>>
>>>>
>>>> On 5/28/14 1:49 PM, Tobias Hartmann wrote:
>>>>> Hi,
>>>>>
>>>>> thanks everyone for the feedback!
>>>>>
>>>>> @Remi: I agree with Paul. This is not a problem because if the normal
>>>>> read sees an outdated null value, a new LambdaForm is created and
>>>>> setCachedLambdaForm(...) is executed. This will guarantee that the
>>>>> non-null value is seen and used. The unnecessary creation of a new
>>>>> LamdaForm is not a problem either.
>>>>>
>>>>> @John: I added the code that you suggested to simulate CAS. Please find
>>>>> the new webrev at:
>>>>>
>>>>> http://cr.openjdk.java.net/~anoll/8005873/webrev.02/
>>>>>
>>>>> Sorry for the delay, I was on vacation.
>>>>>
>>>>> Thanks,
>>>>> Tobias
>>>>>
>>>>> On 19.05.2014 20:31, John Rose wrote:
>>>>>> On May 16, 2014, at 4:56 AM, Tobias Hartmann
>>>>>> <tobias.hartmann at oracle.com> wrote:
>>>>>>
>>>>>>> Is it sufficient then to use synchronized (lambdaForms) { ... } in
>>>>>>> setCachedLambdaForm(..) and a normal read in cachedLambdaForm(..)?
>>>>>> Yes, that is how I see it.  The fast path is a racy non-volatile read
>>>>>> of a safely-published structure.
>>>>>>
>>>>>> (If safe publication via arrays were broken, java.lang.String would be
>>>>>> broken.  But the JMM is carefully designed to support safe publication
>>>>>> of array elements, and through array elements.)
>>>>>>
>>>>>> — John
>>>>>
>>>
>