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8271855: [TESTBUG] Wrong weakCompareAndSet assumption in UnsafeIntrinsicsTest

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Reviewed-by: goetz, thartmann
This commit is contained in:
Martin Doerr 2021-09-29 09:54:59 +00:00
parent 756d22c356
commit c4d115701d
1 changed files with 15 additions and 9 deletions

24
test/hotspot/jtreg/compiler/gcbarriers/UnsafeIntrinsicsTest.java

@ -1,5 +1,5 @@
/* /*
* Copyright (c) 2017, 2020, Oracle and/or its affiliates. All rights reserved. * Copyright (c) 2017, 2021, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
* *
* This code is free software; you can redistribute it and/or modify it * This code is free software; you can redistribute it and/or modify it
@ -24,7 +24,7 @@
/* /*
* @test id=Z * @test id=Z
* @key randomness * @key randomness
* @bug 8059022 * @bug 8059022 8271855
* @modules java.base/jdk.internal.misc:+open * @modules java.base/jdk.internal.misc:+open
* @summary Validate barriers after Unsafe getReference, CAS and swap (GetAndSet) * @summary Validate barriers after Unsafe getReference, CAS and swap (GetAndSet)
* @requires vm.gc.Z * @requires vm.gc.Z
@ -301,7 +301,7 @@ class Runner implements Runnable {
private Node mergeImplCAS(Node startNode, Node expectedNext, Node head) { private Node mergeImplCAS(Node startNode, Node expectedNext, Node head) {
// CAS - should always be true within a single thread - no other thread can have overwritten // CAS - should always be true within a single thread - no other thread can have overwritten
if (!UNSAFE.compareAndSetReference(startNode, offset, expectedNext, head)) { if (!UNSAFE.compareAndSetReference(startNode, offset, expectedNext, head)) {
throw new Error("CAS should always succeed on thread local objects, check you barrier implementation"); throw new Error("CAS should always succeed on thread local objects, check your barrier implementation");
} }
return expectedNext; // continue on old circle return expectedNext; // continue on old circle
} }
@ -309,7 +309,7 @@ class Runner implements Runnable {
private Node mergeImplCASFail(Node startNode, Node expectedNext, Node head) { private Node mergeImplCASFail(Node startNode, Node expectedNext, Node head) {
// Force a fail // Force a fail
if (UNSAFE.compareAndSetReference(startNode, offset, "fail", head)) { if (UNSAFE.compareAndSetReference(startNode, offset, "fail", head)) {
throw new Error("This CAS should always fail, check you barrier implementation"); throw new Error("This CAS should always fail, check your barrier implementation");
} }
if (startNode.next() != expectedNext) { if (startNode.next() != expectedNext) {
throw new Error("Shouldn't have changed"); throw new Error("Shouldn't have changed");
@ -318,9 +318,15 @@ class Runner implements Runnable {
} }
private Node mergeImplWeakCAS(Node startNode, Node expectedNext, Node head) { private Node mergeImplWeakCAS(Node startNode, Node expectedNext, Node head) {
// Weak CAS - should always be true within a single thread - no other thread can have overwritten // Weak CAS - should almost always be true within a single thread - no other thread can have overwritten
if (!UNSAFE.weakCompareAndSetReference(startNode, offset, expectedNext, head)) { // Spurious failures are allowed. So, we retry a couple of times on failure.
throw new Error("Weak CAS should always succeed on thread local objects, check you barrier implementation"); boolean ok = false;
for (int i = 0; i < 3; ++i) {
ok = UNSAFE.weakCompareAndSetReference(startNode, offset, expectedNext, head);
if (ok) break;
}
if (!ok) {
throw new Error("Weak CAS should almost always succeed on thread local objects, check your barrier implementation");
} }
return expectedNext; // continue on old circle return expectedNext; // continue on old circle
} }
@ -328,7 +334,7 @@ class Runner implements Runnable {
private Node mergeImplWeakCASFail(Node startNode, Node expectedNext, Node head) { private Node mergeImplWeakCASFail(Node startNode, Node expectedNext, Node head) {
// Force a fail // Force a fail
if (UNSAFE.weakCompareAndSetReference(startNode, offset, "fail", head)) { if (UNSAFE.weakCompareAndSetReference(startNode, offset, "fail", head)) {
throw new Error("This weak CAS should always fail, check you barrier implementation"); throw new Error("This weak CAS should always fail, check your barrier implementation");
} }
if (startNode.next() != expectedNext) { if (startNode.next() != expectedNext) {
throw new Error("Shouldn't have changed"); throw new Error("Shouldn't have changed");
@ -340,7 +346,7 @@ class Runner implements Runnable {
// CmpX - should always be true within a single thread - no other thread can have overwritten // CmpX - should always be true within a single thread - no other thread can have overwritten
Object res = UNSAFE.compareAndExchangeReference(startNode, offset, expectedNext, head); Object res = UNSAFE.compareAndExchangeReference(startNode, offset, expectedNext, head);
if (!res.equals(expectedNext)) { if (!res.equals(expectedNext)) {
throw new Error("Fail CmpX should always succeed on thread local objects, check you barrier implementation"); throw new Error("Fail CmpX should always succeed on thread local objects, check your barrier implementation");
} }
return expectedNext; // continue on old circle return expectedNext; // continue on old circle
} }