8184181: Use oopDesc::cas_set_mark() instead of raw CAS when accessing oop header
Reviewed-by: dcubed, kbarrett
--- a/hotspot/src/share/vm/runtime/biasedLocking.cpp Mon Jul 17 13:16:33 2017 +0000
+++ b/hotspot/src/share/vm/runtime/biasedLocking.cpp Mon Jul 17 08:43:28 2017 +0200
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2005, 2016, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2005, 2017, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@@ -579,7 +579,7 @@
// the bias of the object.
markOop biased_value = mark;
markOop unbiased_prototype = markOopDesc::prototype()->set_age(mark->age());
- markOop res_mark = (markOop) Atomic::cmpxchg_ptr(unbiased_prototype, obj->mark_addr(), mark);
+ markOop res_mark = obj->cas_set_mark(unbiased_prototype, mark);
if (res_mark == biased_value) {
return BIAS_REVOKED;
}
@@ -594,7 +594,7 @@
// by another thread so we simply return and let the caller deal
// with it.
markOop biased_value = mark;
- markOop res_mark = (markOop) Atomic::cmpxchg_ptr(prototype_header, obj->mark_addr(), mark);
+ markOop res_mark = obj->cas_set_mark(prototype_header, mark);
assert(!(*(obj->mark_addr()))->has_bias_pattern(), "even if we raced, should still be revoked");
return BIAS_REVOKED;
} else if (prototype_header->bias_epoch() != mark->bias_epoch()) {
@@ -609,14 +609,14 @@
assert(THREAD->is_Java_thread(), "");
markOop biased_value = mark;
markOop rebiased_prototype = markOopDesc::encode((JavaThread*) THREAD, mark->age(), prototype_header->bias_epoch());
- markOop res_mark = (markOop) Atomic::cmpxchg_ptr(rebiased_prototype, obj->mark_addr(), mark);
+ markOop res_mark = obj->cas_set_mark(rebiased_prototype, mark);
if (res_mark == biased_value) {
return BIAS_REVOKED_AND_REBIASED;
}
} else {
markOop biased_value = mark;
markOop unbiased_prototype = markOopDesc::prototype()->set_age(mark->age());
- markOop res_mark = (markOop) Atomic::cmpxchg_ptr(unbiased_prototype, obj->mark_addr(), mark);
+ markOop res_mark = obj->cas_set_mark(unbiased_prototype, mark);
if (res_mark == biased_value) {
return BIAS_REVOKED;
}
--- a/hotspot/src/share/vm/runtime/synchronizer.cpp Mon Jul 17 13:16:33 2017 +0000
+++ b/hotspot/src/share/vm/runtime/synchronizer.cpp Mon Jul 17 08:43:28 2017 +0200
@@ -323,7 +323,7 @@
// If the object is stack-locked by the current thread, try to
// swing the displaced header from the BasicLock back to the mark.
assert(dhw->is_neutral(), "invariant");
- if ((markOop) Atomic::cmpxchg_ptr(dhw, object->mark_addr(), mark) == mark) {
+ if (object->cas_set_mark(dhw, mark) == mark) {
TEVENT(fast_exit: release stack-lock);
return;
}
@@ -348,7 +348,7 @@
// Anticipate successful CAS -- the ST of the displaced mark must
// be visible <= the ST performed by the CAS.
lock->set_displaced_header(mark);
- if (mark == (markOop) Atomic::cmpxchg_ptr(lock, obj()->mark_addr(), mark)) {
+ if (mark == obj()->cas_set_mark((markOop) lock, mark)) {
TEVENT(slow_enter: release stacklock);
return;
}
@@ -758,7 +758,7 @@
hash = get_next_hash(Self, obj); // allocate a new hash code
temp = mark->copy_set_hash(hash); // merge the hash code into header
// use (machine word version) atomic operation to install the hash
- test = (markOop) Atomic::cmpxchg_ptr(temp, obj->mark_addr(), mark);
+ test = obj->cas_set_mark(temp, mark);
if (test == mark) {
return hash;
}
@@ -1452,7 +1452,7 @@
m->_recursions = 0;
m->_SpinDuration = ObjectMonitor::Knob_SpinLimit; // Consider: maintain by type/class
- markOop cmp = (markOop) Atomic::cmpxchg_ptr(markOopDesc::INFLATING(), object->mark_addr(), mark);
+ markOop cmp = object->cas_set_mark(markOopDesc::INFLATING(), mark);
if (cmp != mark) {
omRelease(Self, m, true);
continue; // Interference -- just retry
@@ -1547,7 +1547,7 @@
m->_Responsible = NULL;
m->_SpinDuration = ObjectMonitor::Knob_SpinLimit; // consider: keep metastats by type/class
- if (Atomic::cmpxchg_ptr (markOopDesc::encode(m), object->mark_addr(), mark) != mark) {
+ if (object->cas_set_mark(markOopDesc::encode(m), mark) != mark) {
m->set_object(NULL);
m->set_owner(NULL);
m->Recycle();