commit b8a0b94735f188bc739e4c55479c37699006b881
author Ian Rogers <irogers@google.com> Tue Aug 20 18:09:52 2013 -0700
committer Ian Rogers <irogers@google.com> Tue Aug 20 18:11:09 2013 -0700
tree 6620437e5019924f9da7b1c9a6408cf4a113b3e5
parent aa836f7fa2ef359cf8ec1ef98d924f7971ba8352

Switch JNI globals lock to reader-writer.

Also, verifier rejected classes lock. These locks show as contended during
dex2oat, however, they're commonly only read access is required.

Change-Id: If8bb834cc69cd8c26494c87fb7f7b20d4e41cdfd

runtime/gc/collector/mark_sweep.cc

diff --git a/runtime/gc/collector/mark_sweep.cc b/runtime/gc/collector/mark_sweep.cc
index a854971..fd82e2c 100644
--- a/runtime/gc/collector/mark_sweep.cc
+++ b/runtime/gc/collector/mark_sweep.cc
@@ -949,7 +949,7 @@
 
 void MarkSweep::SweepJniWeakGlobals(IsMarkedTester is_marked, void* arg) {
   JavaVMExt* vm = Runtime::Current()->GetJavaVM();
-  MutexLock mu(Thread::Current(), vm->weak_globals_lock);
+  WriterMutexLock mu(Thread::Current(), vm->weak_globals_lock);
   for (const Object** entry : vm->weak_globals) {
     if (!is_marked(*entry, arg)) {
       *entry = kClearedJniWeakGlobal;
@@ -1032,7 +1032,7 @@
   runtime->GetMonitorList()->SweepMonitorList(VerifyIsLiveCallback, this);
 
   JavaVMExt* vm = runtime->GetJavaVM();
-  MutexLock mu(Thread::Current(), vm->weak_globals_lock);
+  ReaderMutexLock mu(Thread::Current(), vm->weak_globals_lock);
   for (const Object** entry : vm->weak_globals) {
     VerifyIsLive(*entry);
   }