RFR(L): 8226705: [REDO] Deoptimize with handshakes

[Daniel D. Daugherty]

Robbin,

This RFR doesn't mention the following bug:

     JDK-8225351 assert failed: Revoke failed, unhandled biased lock state
     https://bugs.openjdk.java.net/browse/JDK-8225351

which is still open. Part of me is wondering if it should be closed as
a duplicate of:

     JDK-8226699 [BACKOUT] JDK-8221734 Deoptimize with handshakes
     https://bugs.openjdk.java.net/browse/JDK-8226699

But the paranoid part of me wonders if this fix:

     JDK-8226705 [REDO] Deoptimize with handshakes
     https://bugs.openjdk.java.net/browse/JDK-8226705

has that base covered... So I figured I would ask on the review
thread to make sure...

Dan



On 8/28/19 3:30 AM, Robbin Ehn wrote:
> Hi all, please consider,
>
> To get away from the issues of us revoking in the handshake, but 
> before deopt
> the locks get re-biased before we hit deopt handler, we instead revoke 
> in deopt
> handler.
> The deopt handler have a JRT_BLOCK/_END which can safepoint so we 
> revoke after
> that but before we start looking at the monitors, with a 
> NoSafepointVerifier.
>
> Here is the previous changeset on top of jdk/jdk tip but due to merge 
> conflicts
> some pieces did not apply:
> http://cr.openjdk.java.net/~rehn/8226705/v1/8226705-8221734-baseline/webrev/ 
>
> So this is what was reviewed.
>
> The rebase (merge conflict resolutions) and 8224795 bug fix :
> http://cr.openjdk.java.net/~rehn/8226705/v1/8226705-rebase/webrev/
>
> Bug 8224795 fix is here:
> http://cr.openjdk.java.net/~rehn/8226705/v1/8226705-rebase/webrev/src/hotspot/share/code/nmethod.cpp.sdiff.html 
>
>
> After this we have the same functionally as the reverted change-set.
>
> Here is the changes for doing the revoke in deopt handler instead:
> http://cr.openjdk.java.net/~rehn/8226705/v1/8226705-revoke-on-deopt/webrev/ 
>
>
> This code was messy adding the deopt revocation in 3 places made it 
> worse.
> Here is a refactoring of that code. (also removed a dead method in 
> biasedlocking):
> http://cr.openjdk.java.net/~rehn/8226705/v1/8226705-refactor/webrev/
>
> And here is full:
> http://cr.openjdk.java.net/~rehn/8226705/v1/full/webrev/
>
> Also a full squashed patch file:
> http://cr.openjdk.java.net/~rehn/8226705/v1/full/full.patch
>
> Latest test run I did t1-t6, Linux/Windows x64 have passed, MacOSX still
> running.
>
> Thanks, Robbin
>
>
>