RFR(M): 8172049: [s390] Implement "JEP 270: Reserved Stack Areas for Critical Sections".

[Doerr, Martin]

Hi Götz,

thank you very much for implementing this change.

I was wondering why you use the compare relation "<=" to compare the stack pointer with the reserved stack activation while all other platforms use "<".
Is it a mistake or is there a reason for it?

Besides that, I only have minor suggestions:
- reserved_stack_check always get Z_R14 as return pc which I think is the only useful argument. So I think it would be better to either remove the argument or to replace the lgr_if_needed by assert(return_pc==Z_R14...).
- In the ad file, the 2 parts of the safepoint poll are directly in juxtaposition with each other. They should better get combined.

Besides this, the change looks very good. I think you have also tested this change in our nightly tests which look good.

Thanks and best regards,
Martin


-----Original Message-----
From: hotspot-runtime-dev [mailto:hotspot-runtime-dev-bounces at openjdk.java.net] On Behalf Of Lindenmaier, Goetz
Sent: Mittwoch, 28. Dezember 2016 08:41
To: hotspot-runtime-dev at openjdk.java.net
Subject: RFR(M): 8172049: [s390] Implement "JEP 270: Reserved Stack Areas for Critical Sections".

Hi,

This implements JEP 270 on s390.
It's s390-only except for enabling the test, thus I need a sponsor.
Please review.
http://cr.openjdk.java.net/~goetz/wr16/8172049-s390_reservedStack/webrev.01/

Best regards,
  Goetz.