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8167108: inconsistent handling of SR_lock can lead to crashes

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Add Thread Safe Memory Reclamation (Thread-SMR) mechanism.

Co-authored-by: Erik Osterlund <erik.osterlund@oracle.com>
Co-authored-by: Robbin Ehn <robbin.ehn@oracle.com>
Reviewed-by: coleenp, dcubed, dholmes, eosterlund, gthornbr, kbarrett, rehn, sspitsyn, stefank
This commit is contained in:
Daniel D. Daugherty 2017-11-22 17:54:50 -08:00
parent cd0c6d0fae
commit 0dff96ff0b
67 changed files with 4220 additions and 995 deletions
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125
src/hotspot/share/runtime/biasedLocking.cpp
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@ -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 @@ static BiasedLocking::Condition revoke_bias(oop obj, bool allow_rebias, bool is_
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 @@ static BiasedLocking::Condition bulk_revoke_or_rebias_at_safepoint(oop o,
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 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 (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.
// 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()) {
// 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));
}
}
}
}
// 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);
}
}
}
// 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);
}
// 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 = 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 BiasedLocking::Condition bulk_revoke_or_rebias_at_safepoint(oop o,
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 @@ void BiasedLocking::preserve_marks() {
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()) {