RFR(S) 8238585: Use handshake for JvmtiEventControllerPrivate::enter_interp_only_mode() and don't make compiled methods on stack not_entrant

[serguei.spitsyn at oracle.com]

Hi Richard,


On 6/5/20 00:18, Reingruber, Richard wrote:
> Hi,
>
>> The mach5 test run is good.
> Thanks Serguei and thanks to everybody providing feedback! I just pushed the change.

Great, thanks!

> Just curious: is mach5 an alias for tier5?

The mach5 is a build and test system which also provides CI.
Tier5 is one of the testing levels.

>   And is this mach5 the same as in "Job:
> mach5-one-rrich-JDK-8238585-2-20200604-1334-11519059" which is the (successful) submit repo job?

Yes. I guess all mach5 jobs have this prefix.

Thanks,
Serguei

>
> Thanks,
> Richard.
>
> -----Original Message-----
> From: serguei.spitsyn at oracle.com <serguei.spitsyn at oracle.com>
> Sent: Donnerstag, 4. Juni 2020 04:07
> To: Reingruber, Richard <richard.reingruber at sap.com>; serviceability-dev at openjdk.java.net; hotspot-compiler-dev at openjdk.java.net; hotspot-runtime-dev at openjdk.java.net; hotspot-gc-dev at openjdk.java.net
> Subject: Re: RFR(S) 8238585: Use handshake for JvmtiEventControllerPrivate::enter_interp_only_mode() and don't make compiled methods on stack not_entrant
>
> Hi Richard,
>
> The mach5 test run is good.
>
> Thanks,
> Serguei
>
>
> On 6/2/20 10:57, Reingruber, Richard wrote:
>> Hi Serguei,
>>
>>> This looks good to me.
>> Thanks!
>>
>>   From an earlier mail:
>>
>>> I'm thinking it would be more safe to run full tier5.
>> I guess we're done with reviewing. Would be good if you could run full tier5 now. After that I would
>> like to push.
>>
>> Thanks, Richard.
>>
>> -----Original Message-----
>> From: serguei.spitsyn at oracle.com <serguei.spitsyn at oracle.com>
>> Sent: Dienstag, 2. Juni 2020 18:55
>> To: Vladimir Kozlov <vladimir.kozlov at oracle.com>; Reingruber, Richard <richard.reingruber at sap.com>; serviceability-dev at openjdk.java.net; hotspot-compiler-dev at openjdk.java.net; hotspot-runtime-dev at openjdk.java.net; hotspot-gc-dev at openjdk.java.net
>> Subject: Re: RFR(S) 8238585: Use handshake for JvmtiEventControllerPrivate::enter_interp_only_mode() and don't make compiled methods on stack not_entrant
>>
>> Hi Richard,
>>
>> This looks good to me.
>>
>> Thanks,
>> Serguei
>>
>>
>> On 5/28/20 09:02, Vladimir Kozlov wrote:
>>> Vladimir Ivanov is on break currently.
>>> It looks good to me.
>>>
>>> Thanks,
>>> Vladimir K
>>>
>>> On 5/26/20 7:31 AM, Reingruber, Richard wrote:
>>>> Hi Vladimir,
>>>>
>>>>>> Webrev: http://cr.openjdk.java.net/~rrich/webrevs/8238585/webrev.0/
>>>>> Not an expert in JVMTI code base, so can't comment on the actual
>>>>> changes.
>>>>>     From JIT-compilers perspective it looks good.
>>>> I put out webrev.1 a while ago [1]:
>>>>
>>>> Webrev: http://cr.openjdk.java.net/~rrich/webrevs/8238585/webrev.1/
>>>> Webrev(delta):
>>>> http://cr.openjdk.java.net/~rrich/webrevs/8238585/webrev.1.inc/
>>>>
>>>> You originally suggested to use a handshake to switch a thread into
>>>> interpreter mode [2]. I'm using
>>>> a direct handshake now, because I think it is the best fit.
>>>>
>>>> May I ask if webrev.1 still looks good to you from JIT-compilers
>>>> perspective?
>>>>
>>>> Can I list you as (partial) Reviewer?
>>>>
>>>> Thanks, Richard.
>>>>
>>>> [1]
>>>> http://mail.openjdk.java.net/pipermail/serviceability-dev/2020-April/031245.html
>>>> [2]
>>>> http://mail.openjdk.java.net/pipermail/serviceability-dev/2020-January/030340.html
>>>>
>>>> -----Original Message-----
>>>> From: Vladimir Ivanov <vladimir.x.ivanov at oracle.com>
>>>> Sent: Freitag, 7. Februar 2020 09:19
>>>> To: Reingruber, Richard <richard.reingruber at sap.com>;
>>>> serviceability-dev at openjdk.java.net;
>>>> hotspot-compiler-dev at openjdk.java.net
>>>> Subject: Re: RFR(S) 8238585: Use handshake for
>>>> JvmtiEventControllerPrivate::enter_interp_only_mode() and don't make
>>>> compiled methods on stack not_entrant
>>>>
>>>>
>>>>> Webrev: http://cr.openjdk.java.net/~rrich/webrevs/8238585/webrev.0/
>>>> Not an expert in JVMTI code base, so can't comment on the actual
>>>> changes.
>>>>
>>>>     From JIT-compilers perspective it looks good.
>>>>
>>>> Best regards,
>>>> Vladimir Ivanov
>>>>
>>>>> Bug: https://bugs.openjdk.java.net/browse/JDK-8238585
>>>>>
>>>>> The change avoids making all compiled methods on stack not_entrant
>>>>> when switching a java thread to
>>>>> interpreter only execution for jvmti purposes. It is sufficient to
>>>>> deoptimize the compiled frames on stack.
>>>>>
>>>>> Additionally a handshake is used instead of a vm operation to walk
>>>>> the stack and do the deoptimizations.
>>>>>
>>>>> Testing: JCK and JTREG tests, also in Xcomp mode with fastdebug and
>>>>> release builds on all platforms.
>>>>>
>>>>> Thanks, Richard.
>>>>>
>>>>> See also my question if anyone knows a reason for making the
>>>>> compiled methods not_entrant:
>>>>> http://mail.openjdk.java.net/pipermail/serviceability-dev/2020-January/030339.html
>>>>>
>>>>>