--- a/src/hotspot/share/runtime/biasedLocking.cpp Wed Nov 22 14:31:48 2017 -0500
+++ b/src/hotspot/share/runtime/biasedLocking.cpp Wed Nov 22 17:54:50 2017 -0800
@@ -32,6 +32,7 @@
#include "runtime/basicLock.hpp"
#include "runtime/biasedLocking.hpp"
#include "runtime/task.hpp"
+#include "runtime/threadSMR.hpp"
#include "runtime/vframe.hpp"
#include "runtime/vmThread.hpp"
#include "runtime/vm_operations.hpp"
@@ -214,12 +215,8 @@
if (requesting_thread == biased_thread) {
thread_is_alive = true;
} else {
- for (JavaThread* cur_thread = Threads::first(); cur_thread != NULL; cur_thread = cur_thread->next()) {
- if (cur_thread == biased_thread) {
- thread_is_alive = true;
- break;
- }
- }
+ ThreadsListHandle tlh;
+ thread_is_alive = tlh.includes(biased_thread);
}
if (!thread_is_alive) {
if (allow_rebias) {
@@ -390,72 +387,76 @@
Klass* k_o = o->klass();
Klass* klass = k_o;
- if (bulk_rebias) {
- // Use the epoch in the klass of the object to implicitly revoke
- // all biases of objects of this data type and force them to be
- // reacquired. However, we also need to walk the stacks of all
- // threads and update the headers of lightweight locked objects
- // with biases to have the current epoch.
+ {
+ JavaThreadIteratorWithHandle jtiwh;
+
+ if (bulk_rebias) {
+ // Use the epoch in the klass of the object to implicitly revoke
+ // all biases of objects of this data type and force them to be
+ // reacquired. However, we also need to walk the stacks of all
+ // threads and update the headers of lightweight locked objects
+ // with biases to have the current epoch.
+
+ // If the prototype header doesn't have the bias pattern, don't
+ // try to update the epoch -- assume another VM operation came in
+ // and reset the header to the unbiased state, which will
+ // implicitly cause all existing biases to be revoked
+ if (klass->prototype_header()->has_bias_pattern()) {
+ int prev_epoch = klass->prototype_header()->bias_epoch();
+ klass->set_prototype_header(klass->prototype_header()->incr_bias_epoch());
+ int cur_epoch = klass->prototype_header()->bias_epoch();
- // If the prototype header doesn't have the bias pattern, don't
- // try to update the epoch -- assume another VM operation came in
- // and reset the header to the unbiased state, which will
- // implicitly cause all existing biases to be revoked
- if (klass->prototype_header()->has_bias_pattern()) {
- int prev_epoch = klass->prototype_header()->bias_epoch();
- klass->set_prototype_header(klass->prototype_header()->incr_bias_epoch());
- int cur_epoch = klass->prototype_header()->bias_epoch();
+ // Now walk all threads' stacks and adjust epochs of any biased
+ // and locked objects of this data type we encounter
+ for (; JavaThread *thr = jtiwh.next(); ) {
+ GrowableArray<MonitorInfo*>* cached_monitor_info = get_or_compute_monitor_info(thr);
+ for (int i = 0; i < cached_monitor_info->length(); i++) {
+ MonitorInfo* mon_info = cached_monitor_info->at(i);
+ oop owner = mon_info->owner();
+ markOop mark = owner->mark();
+ if ((owner->klass() == k_o) && mark->has_bias_pattern()) {
+ // We might have encountered this object already in the case of recursive locking
+ assert(mark->bias_epoch() == prev_epoch || mark->bias_epoch() == cur_epoch, "error in bias epoch adjustment");
+ owner->set_mark(mark->set_bias_epoch(cur_epoch));
+ }
+ }
+ }
+ }
- // Now walk all threads' stacks and adjust epochs of any biased
- // and locked objects of this data type we encounter
- for (JavaThread* thr = Threads::first(); thr != NULL; thr = thr->next()) {
+ // At this point we're done. All we have to do is potentially
+ // adjust the header of the given object to revoke its bias.
+ revoke_bias(o, attempt_rebias_of_object && klass->prototype_header()->has_bias_pattern(), true, requesting_thread, NULL);
+ } else {
+ if (log_is_enabled(Info, biasedlocking)) {
+ ResourceMark rm;
+ log_info(biasedlocking)("* Disabling biased locking for type %s", klass->external_name());
+ }
+
+ // Disable biased locking for this data type. Not only will this
+ // cause future instances to not be biased, but existing biased
+ // instances will notice that this implicitly caused their biases
+ // to be revoked.
+ klass->set_prototype_header(markOopDesc::prototype());
+
+ // Now walk all threads' stacks and forcibly revoke the biases of
+ // any locked and biased objects of this data type we encounter.
+ for (; JavaThread *thr = jtiwh.next(); ) {
GrowableArray<MonitorInfo*>* cached_monitor_info = get_or_compute_monitor_info(thr);
for (int i = 0; i < cached_monitor_info->length(); i++) {
MonitorInfo* mon_info = cached_monitor_info->at(i);
oop owner = mon_info->owner();
markOop mark = owner->mark();
if ((owner->klass() == k_o) && mark->has_bias_pattern()) {
- // We might have encountered this object already in the case of recursive locking
- assert(mark->bias_epoch() == prev_epoch || mark->bias_epoch() == cur_epoch, "error in bias epoch adjustment");
- owner->set_mark(mark->set_bias_epoch(cur_epoch));
+ revoke_bias(owner, false, true, requesting_thread, NULL);
}
}
}
- }
- // At this point we're done. All we have to do is potentially
- // adjust the header of the given object to revoke its bias.
- revoke_bias(o, attempt_rebias_of_object && klass->prototype_header()->has_bias_pattern(), true, requesting_thread, NULL);
- } else {
- if (log_is_enabled(Info, biasedlocking)) {
- ResourceMark rm;
- log_info(biasedlocking)("* Disabling biased locking for type %s", klass->external_name());
+ // Must force the bias of the passed object to be forcibly revoked
+ // as well to ensure guarantees to callers
+ revoke_bias(o, false, true, requesting_thread, NULL);
}
-
- // Disable biased locking for this data type. Not only will this
- // cause future instances to not be biased, but existing biased
- // instances will notice that this implicitly caused their biases
- // to be revoked.
- klass->set_prototype_header(markOopDesc::prototype());
-
- // Now walk all threads' stacks and forcibly revoke the biases of
- // any locked and biased objects of this data type we encounter.
- for (JavaThread* thr = Threads::first(); thr != NULL; thr = thr->next()) {
- GrowableArray<MonitorInfo*>* cached_monitor_info = get_or_compute_monitor_info(thr);
- for (int i = 0; i < cached_monitor_info->length(); i++) {
- MonitorInfo* mon_info = cached_monitor_info->at(i);
- oop owner = mon_info->owner();
- markOop mark = owner->mark();
- if ((owner->klass() == k_o) && mark->has_bias_pattern()) {
- revoke_bias(owner, false, true, requesting_thread, NULL);
- }
- }
- }
-
- // Must force the bias of the passed object to be forcibly revoked
- // as well to ensure guarantees to callers
- revoke_bias(o, false, true, requesting_thread, NULL);
- }
+ } // ThreadsListHandle is destroyed here.
log_info(biasedlocking)("* Ending bulk revocation");
@@ -481,7 +482,7 @@
static void clean_up_cached_monitor_info() {
// Walk the thread list clearing out the cached monitors
- for (JavaThread* thr = Threads::first(); thr != NULL; thr = thr->next()) {
+ for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thr = jtiwh.next(); ) {
thr->set_cached_monitor_info(NULL);
}
}
@@ -768,7 +769,7 @@
ResourceMark rm;
Thread* cur = Thread::current();
- for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
+ for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next(); ) {
if (thread->has_last_Java_frame()) {
RegisterMap rm(thread);
for (javaVFrame* vf = thread->last_java_vframe(&rm); vf != NULL; vf = vf->java_sender()) {