hg: jdk/submit: 8240918: [REDO] Allow direct handshakes without VMThread intervention

[patricio.chilano.mateo at oracle.com]

Changeset: e2faa00e8d67
Author:    pchilanomate
Date:      2020-04-08 18:32 +0000
URL:       https://hg.openjdk.java.net/jdk/submit/rev/e2faa00e8d67

8240918: [REDO] Allow direct handshakes without VMThread intervention
Summary: REDO of 8230594
Reviewed-by: dholmes, rehn, mdoerr, coleenp, dcubed

! src/hotspot/share/runtime/biasedLocking.cpp
! src/hotspot/share/runtime/handshake.cpp
! src/hotspot/share/runtime/handshake.hpp
! src/hotspot/share/runtime/mutexLocker.cpp
! src/hotspot/share/runtime/safepoint.cpp
! src/hotspot/share/runtime/safepointMechanism.inline.hpp
! src/hotspot/share/runtime/thread.cpp
! src/hotspot/share/runtime/thread.hpp
! src/hotspot/share/runtime/threadSMR.hpp
+ test/hotspot/jtreg/runtime/handshake/HandshakeDirectTest.java