Re: [11u] Backport JEP 346 : Promptly Return Unused Committed Memory from G1

[Liang Mao]

Hi Thomas,

I agree that we should move forward very carefully to make sure we won't break anything.
In another mail I explained my thinkings about the quality concerns. We need full discussion
on details and confirm everything goes fine. I guess Oracle G1 team may not give the commitment
 to back this backport because 11u is already maintained by community now but previously Oracle
G1 team agreed to help the review.

Thanks,
Liang



------------------------------------------------------------------
From:Thomas Stüfe <thomas.stuefe at gmail.com>
Send Time:2020 Oct. 23 (Fri.) 13:24
To:Andrew Haley <aph at redhat.com>
Cc:rs <rs at jelastic.com>; "MAO, Liang" <maoliang.ml at alibaba-inc.com>; jdk-updates-dev <jdk-updates-dev at openjdk.java.net>; "Lindenmaier, Goetz" <goetz.lindenmaier at sap.com>; Martijn Verburg <Martijn.Verburg at microsoft.com>
Subject:Re: [11u] Backport JEP 346 : Promptly Return Unused Committed Memory from G1

Hi,

I am a bit concerned about this.

We are in the process of gently nudging our internal customers up to jdk 11 from jdk 8. We are also internally providing an "11ified" jdk 8, similar to the old hotspot express model. So hotspot 11 gets used alot in our company and in a lot of very different scenarios. Elasticity is welcome, but any destabilization of G1 would be catastrophic.

As a counter example, the Shenandoah backport makes me feel less apprehensive since I know that RedHat has a strong commitment to backport releases and that the Shenandoah developers work focused on Shenandoah in the main line (so their resources are not split between different GCs). I'd feel safer if I had a similar commitment from Oracle G1 developers about backing this backport. Do we have that (I may have missed this)?

And as Aleksey wrote in his initial review, a killswitch - where "off" is a reliably tested scenario - would be good.

Thanks, Thomas
On Mon, Oct 12, 2020 at 11:36 AM Andrew Haley <aph at redhat.com> wrote:
On 12/10/2020 09:02, Ruslan Synytsky wrote:
 > Dear Liang, thank you for the extra efforts on this improvement. 
 > 
 > Dear Andrew, I assume we need your approval / confirmation. Can you please take a look and let us know your feedback? 

 OK, I'll have a look and get some input from others.

 -- 
 Andrew Haley  (he/him)
 Java Platform Lead Engineer
 Red Hat UK Ltd. <https://www.redhat.com>
https://keybase.io/andrewhaley
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