[11u] RFR: 8209061 & 8209062: G1MonitoringSupport changes

[Langer, Christoph]

Hi,

I've just looked at approving this series of backports (JDK-8209061, JDK-8209062 and JDK-8207200).

While I'm sure that JDK-8207200 fixes an important issue and I also trust your reviews of the backports, I can see that these 3 patches together mean some significant changes in the area of G1 GC. This makes me kind of hesitant to approve the backports right away. I'd like to get some assessment/reassurance of the other JDK11 maintainers (aph, sgehwolf) on whether we should admit them or not?

Also, Aleksey, maybe you can give some technical advice as a gc expert if you think these backports are feasible?

Another thing: Looking at JBS I can see that JDK-8208498 was marked as a blocker for JDK-8209061 and the former hasn't been backported to 11. Is that an issue?

Generally, would it be possible to fix the issue of JDK-8207200 in a way that's less invasive?

Please understand that I'd like to err on the side of caution here...

Thanks & Best regards
Christoph

> -----Original Message-----
> From: jdk-updates-dev <jdk-updates-dev-retn at openjdk.java.net> On
> Behalf Of John Cuthbertson
> Sent: Dienstag, 15. September 2020 19:07
> To: Vladimir Kempik <vkempik at azul.com>
> Cc: jdk-updates-dev at openjdk.java.net
> Subject: Re: [11u] RFR: 8209061 & 8209062: G1MonitoringSupport changes
> 
> Hi Vladimir,
> 
> On Sep 3, 2020, at 5:28 AM, Vladimir Kempik
> <vkempik at azul.com<mailto:vkempik at azul.com>> wrote:
> 
> Hello
> 
> Please review these backports of JDK-8209061:Move G1 serviceability
> functionality to G1MonitoringSupport  and JDK-8209062:Clean up
> G1MonitoringSupport to jdk11u
> 
> These backports are prerequestes for JDK-8207200 which we can see in the
> wild with jdk8 and jdk11.
> 
> JDK-8209061 and JDK-8209062 applies mostly clean, very few places where it
> wasn’t clean due to surrounding code or code layout.
> 
> after these two, JDK-8207200 applies cleanly.
> 
> Testing: tier1.
> 
> The webrevs:
> 
> http://cr.openjdk.java.net/~vkempik/8209061/webrev.00/
> 
> This looks good to me and matches
> http://hg.openjdk.java.net/jdk/jdk/rev/ec014e5694ec.
> 
> http://cr.openjdk.java.net/~vkempik/8209062/webrev.00/
> 
> This looks good to me also and matches
> http://hg.openjdk.java.net/jdk/jdk/rev/9a5200b84046.
> 
> 
> All mentioned bugs:
> https://bugs.openjdk.java.net/browse/JDK-8209062
> https://bugs.openjdk.java.net/browse/JDK-8209061
> https://bugs.openjdk.java.net/browse/JDK-8207200
> 
> Original changesets:
> 8209061: http://hg.openjdk.java.net/jdk/jdk/rev/ec014e5694ec
> 8209062: http://hg.openjdk.java.net/jdk/jdk/rev/9a5200b84046
> 
> Thanks, Vladimir
> 
> Regards,
> 
> JohnC