Remove unneeded ScopedGCCriticalSections from openjdkjvmti.
We used ScopedGCCriticalSections in many parts of the openjdkjvmti
often unnecessarily.
We removed a totally unneeded GCCriticalSection that was acquired when
modifying the instrumentation listeners.
We also removed RequestGCSafeSynchronousCheckpoint and the change to
use GcRoots instead. We added RequestGCSafeSynchronousCheckpoint as a
way to prevent the GC from running when we are doing some JVMTI
operations on other threads. This could interact with running GCs in
non-trivial ways, potentially causing deadlocks in some situations.
This changes the code to instead use read-barriers and GcRoots to
ensure that we do not read data from the wrong gc space.
In order for this to work correctly we need to make sure that we are
only ever reading the GcRoots from the thread that eventually needs
the reference. This required some re-writing of the checkpoint
closures since they would often just call AddLocalReference on
non-local Thread objects.
Changes to Thread::RequestSynchronousCheckpoint and art::Barrier were
needed in order to allow this all to work since we needed to ensure
that the requesting thread did not suspend as the checkpoint was being
run.
This is a partial revert of commit 7585b91bfc77b8.
Bug: 67838964
Bug: 76003243
Test: use gapid
Test: ./test.py --host -j50
Test: ./art/tools/run-libjdwp-tests.sh --mode=host
Merged-In: I26d871089829639eccb973cecc315194f7bcf681
Change-Id: I26d871089829639eccb973cecc315194f7bcf681
(cherry picked from commit 318afe6c3ac1e734adbd769bbf22b8c7e373e80b)
10 files changed