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

[Langer, Christoph]

Hi Aleksey,

I'm wondering whether you could give an assessment about these changes, similar to what you've done regarding the proposed backport of JEP 346? I would hope this one would be less effort...

Thanks
Christoph

> -----Original Message-----
> From: Vladimir Kempik <vkempik at azul.com>
> Sent: Dienstag, 13. Oktober 2020 22:01
> To: Langer, Christoph <christoph.langer at sap.com>
> Cc: John Cuthbertson <johnc at azul.com>; Andrew Haley
> <aph at redhat.com>; Severin Gehwolf <sgehwolf at redhat.com>; Aleksey
> Shipilev <shade at redhat.com>; jdk-updates-dev at openjdk.java.net
> Subject: Re: [11u] RFR: 8209061 & 8209062: G1MonitoringSupport changes
> 
> Hello
> 
> Any objections about these patches ?
> 
> Regards, Vladimir.
> 
> > 17 сент. 2020 г., в 11:24, Vladimir Kempik <vkempik at azul.com>
> написал(а):
> >
> > Hello Langer
> >
> >> 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?
> >
> > well, I have tried to make 8207200 less invasive by not including 8208498.
> >
> > There is a race condition in g1 monitoring which still can be see by some
> openjdk11 users ( commited < used) and this is the attempt to fix it.
> > I have verified it helps at least one user. Sadly I don’t have a reproducer.
> >
> > Regards, Vladimir
> >
> >
> >> 17 сент. 2020 г., в 10:43, Langer, Christoph <christoph.langer at sap.com>
> написал(а):
> >>
> >> 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
> >