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

Robbin Ehn robbin.ehn at oracle.com
Wed Aug 28 09:57:57 UTC 2019

Hi, hotspot-dev was the intended list.

Thanks, Robbin

On 2019-08-28 09:30, 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

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