git: openjdk/mobile: 8240918: [REDO] Allow direct handshakes without VMThread intervention

[duke]

Changeset: 89a33e69
Author:    Patricio Chilano Mateo <pchilanomate at openjdk.org>
Date:      2020-04-08 18:32:21 +0000
URL:       https://git.openjdk.java.net/mobile/commit/89a33e69

8240918: [REDO] Allow direct handshakes without VMThread intervention

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