RFR: 8324683: Unify AttachListener code for Posix platforms [v3]

[Thomas Stuefe]

On Fri, 12 Apr 2024 10:14:45 GMT, Martin Doerr <mdoerr at openjdk.org> wrote:

> > > Maybe you could take my stuff and consolidate it with yours so we can get closer to the number of lines deleted that my PR has, or even beat it :-)?
> > > All the best, Johan
> > 
> > 
> > Hi @jdksjolen,
> > Duplicate work is always annoying, sorry. To our defense, @SoniaZaldana 's work has been going on for many weeks now out in the open.
> > I advised her to leave AIX out of the patch for several reasons:
> > When analyzing the differences, we found a number of sublteties that may break AIX, and we have no easy way to check that platform. From my time as AIX porter I remember that the attach listener framework on AIX was exceptionally brittle and took a lot of grooming to get right.
> > Since the current AIX porters are really overworked atm and the last thing they need are regressions, I would leave the AIX code base as it is for now. Let the porters deal with this if/when they find time. Importantly, they then also can double-check whether many of the old workarounds we added back in the early 2000's (eg those close/shutdown workarounds) are still needed in modern AIX versions.
> > Or, what do you think @TheRealMDoerr?
> > Therefore, I would rather see Sonia's patch in its current form go in.
> 
> AIX work in this area is typically done by @JoKern65 or @varada1110. Maybe you would like to take a look. It's probably ok to do AIX later, but I can't tell if the new code will make that harder or easier.

The main work would be understanding the code, AIX, and the history of its bugs in this area. And then pulling out all outdated workarounds preventing AIX from just using the (POSIX compliant) attach listener shared code. This PR does not break anything for AIX and makes it actually easier to do such cleanup work.

Thinking about this, that follow-up work could be substantial and should frankly be done by companies interested in the AIX port. This PR has been in review for a long time now, and we need Sonia for other stuff :-). Therefore I would be really thankful if we could tie this up soon.

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PR Comment: https://git.openjdk.org/jdk/pull/18283#issuecomment-2051708283