[jdk11u] Backport the fix of JDK-8180450 to JDK 11?

[Andrew Haley]

On 10/17/24 09:14, Lindenmaier, Goetz wrote:

> This is a big improvement of performance for subtype checking.
> But it is also a big change in central parts of the JVM.
> Also, the performance issue solved here is not a regression in
> 17 (or 11).

I don't understand. What's the relevance of whether it's a regression?

> So I think while we could consider this for the latest LTE, 21,
> we should not bring this to 17 or older releases.  It's just too
> risky for these.
> Even for 21 it would be a considerable effort to backport it
> along with the needed follow-up issues.

As far as I know there are no needed follow-up issues. It's pretty
self contained. The patch is written in a way that makes backports
possible.

>> I'm not sure. Looking at the rules for backporting, any bug fix "which
>> contributes to the stability, security or performance of the affected line should
>> be considered." So this definitely fits in the rule of what is allowed in 11u, but
>> of course that doesn't mean that it will be backported, merely that it will be
>> considered.
> Anyways, in 11 it says "Please note that these common rules do not allow
> enhancements to be back-ported, only fixes to bugs."
 > https://wiki.openjdk.org/display/JDKUpdates/JDK11u> and I would rather categorize it as an enhancement than a bug, although
> it's filed as bug in JBS.

Well, that's a discussion we can have, I suppose, but it's always been
a bug, going back years. I guess there's a grey area.

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