Integrated: 8266963: Remove safepoint poll introduced in 8262443 due to reentrance issue

[Yude Lin]

On Fri, 14 May 2021 08:01:12 GMT, Yude Lin <github.com+16811675+linade at openjdk.org> wrote:

> Shenandoah hangs when running specjvm2008 derby. The reason is a Java Thread reenters safepoint/handshake and blocks on itself. Please checkout the bugid for more details. After discussion with @zhengyu123, we think this might not be Shenandoah-specific. I propose to add a check before processing the safepoint/handshake.
> 
> An alternative approach (also insight from @zhengyu123) is to move the check a little earlier to the specific place where the Java Thread do ThreadBlockInVM. To feel reassured that no more reentrance exists in other places, I still leave the check in safepoint/handshake as debug code. See https://github.com/openjdk/jdk/compare/master...linade:reentrancecond
> 
> I'd appreciate more of your thoughts on these as I understand it could be a rather critical part of the code.

This pull request has now been integrated.

Changeset: 9c346a1e
Author:    Yude Lin <yude.lyd at alibaba-inc.com>
Committer: David Holmes <dholmes at openjdk.org>
URL:       https://git.openjdk.java.net/jdk/commit/9c346a1ec78b45c61fbfc76961dc5674cfd98520
Stats:     14 lines in 2 files changed: 2 ins; 9 del; 3 mod

8266963: Remove safepoint poll introduced in 8262443 due to reentrance issue

Reviewed-by: rehn, zgu, dholmes

-------------

PR: https://git.openjdk.java.net/jdk/pull/4028