--- old/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp 2013-11-06 17:33:42.506555482 +0100 +++ new/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp 2013-11-06 17:33:42.398555484 +0100 @@ -6656,13 +6656,18 @@ if (!oopDesc::is_null(heap_oop)) { oop obj = oopDesc::decode_heap_oop_not_null(heap_oop); HeapRegion* hr = _g1h->heap_region_containing(obj); - assert(!hr->isHumongous(), "code root in humongous region?"); + assert(!hr->continuesHumongous(), + err_msg("trying to add code root "PTR_FORMAT" in continuation of humongous region "HR_FORMAT + " starting at "HR_FORMAT, + _nm, HR_FORMAT_PARAMS(hr), HR_FORMAT_PARAMS(hr->humongous_start_region()))); // HeapRegion::add_strong_code_root() avoids adding duplicate // entries but having duplicates is OK since we "mark" nmethods // as visited when we scan the strong code root lists during the GC. hr->add_strong_code_root(_nm); - assert(hr->rem_set()->strong_code_roots_list_contains(_nm), "add failed?"); + assert(hr->rem_set()->strong_code_roots_list_contains(_nm), + err_msg("failed to add code root "PTR_FORMAT" to remembered set of region "HR_FORMAT, + _nm, HR_FORMAT_PARAMS(hr))); } } @@ -6683,9 +6688,15 @@ if (!oopDesc::is_null(heap_oop)) { oop obj = oopDesc::decode_heap_oop_not_null(heap_oop); HeapRegion* hr = _g1h->heap_region_containing(obj); - assert(!hr->isHumongous(), "code root in humongous region?"); + assert(!hr->continuesHumongous(), + err_msg("trying to remove code root "PTR_FORMAT" in continuation of humongous region "HR_FORMAT + " starting at "HR_FORMAT, + _nm, HR_FORMAT_PARAMS(hr), HR_FORMAT_PARAMS(hr->humongous_start_region()))); + hr->remove_strong_code_root(_nm); - assert(!hr->rem_set()->strong_code_roots_list_contains(_nm), "remove failed?"); + assert(!hr->rem_set()->strong_code_roots_list_contains(_nm), + err_msg("failed to remove code root "PTR_FORMAT" of region "HR_FORMAT, + _nm, HR_FORMAT_PARAMS(hr))); } } @@ -6716,7 +6727,9 @@ class MigrateCodeRootsHeapRegionClosure: public HeapRegionClosure { public: bool doHeapRegion(HeapRegion *hr) { - assert(!hr->isHumongous(), "humongous region in collection set?"); + assert(!hr->isHumongous(), + err_msg("humongous region "HR_FORMAT" should not have been added to collection set", + HR_FORMAT_PARAMS(hr))); hr->migrate_strong_code_roots(); return false; } @@ -6796,9 +6809,13 @@ bool doHeapRegion(HeapRegion *hr) { HeapRegionRemSet* hrrs = hr->rem_set(); - if (hr->isHumongous()) { - // Code roots should never be attached to a humongous region - assert(hrrs->strong_code_roots_list_length() == 0, "sanity"); + if (hr->continuesHumongous()) { + // Code roots should never be attached to a continuation of a humongous region + assert(hrrs->strong_code_roots_list_length() == 0, + err_msg("code roots should never be attached to continuations of humongous region "HR_FORMAT + " starting at "HR_FORMAT", but has "INT32_FORMAT, + HR_FORMAT_PARAMS(hr), HR_FORMAT_PARAMS(hr->humongous_start_region()), + hrrs->strong_code_roots_list_length())); return false; } --- old/src/share/vm/gc_implementation/g1/heapRegion.cpp 2013-11-06 17:33:43.022555477 +0100 +++ new/src/share/vm/gc_implementation/g1/heapRegion.cpp 2013-11-06 17:33:42.934555478 +0100 @@ -601,7 +601,9 @@ void HeapRegion::migrate_strong_code_roots() { assert(in_collection_set(), "only collection set regions"); - assert(!isHumongous(), "not humongous regions"); + assert(!isHumongous(), + err_msg("humongous region "HR_FORMAT" should not have been added to collection set", + HR_FORMAT_PARAMS(this))); HeapRegionRemSet* hrrs = rem_set(); hrrs->migrate_strong_code_roots(); @@ -722,12 +724,11 @@ return; } - // An H-region should have an empty strong code root list - if (isHumongous()) { + if (continuesHumongous()) { if (strong_code_roots_length > 0) { - gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] is humongous " - "but has "INT32_FORMAT" code root entries", - bottom(), end(), strong_code_roots_length); + gclog_or_tty->print_cr("region "HR_FORMAT" is a continuation of a humongous " + "region but has "INT32_FORMAT" code root entries", + HR_FORMAT_PARAMS(this), strong_code_roots_length); *failures = true; } return; --- old/src/share/vm/gc_implementation/g1/heapRegionRemSet.cpp 2013-11-06 17:33:43.390555472 +0100 +++ new/src/share/vm/gc_implementation/g1/heapRegionRemSet.cpp 2013-11-06 17:33:43.310555473 +0100 @@ -1004,7 +1004,9 @@ void HeapRegionRemSet::migrate_strong_code_roots() { assert(hr()->in_collection_set(), "only collection set regions"); - assert(!hr()->isHumongous(), "not humongous regions"); + assert(!hr()->isHumongous(), + err_msg("humongous region "HR_FORMAT" should not have been added to the collection set", + HR_FORMAT_PARAMS(hr()))); ResourceMark rm; --- /dev/null 2013-11-06 09:04:16.963484996 +0100 +++ new/test/gc/g1/TestHumongousCodeCacheRoots.java 2013-11-06 17:33:43.726555469 +0100 @@ -0,0 +1,143 @@ +/* + * Copyright (c) 2013, 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 + * under the terms of the GNU General Public License version 2 only, as + * published by the Free Software Foundation. + * + * This code is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + * version 2 for more details (a copy is included in the LICENSE file that + * accompanied this code). + * + * You should have received a copy of the GNU General Public License version + * 2 along with this work; if not, write to the Free Software Foundation, + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. + * + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA + * or visit www.oracle.com if you need additional information or have any + * questions. + */ + +/* + * @test + * @key regression + * @key gc + * @bug 8027756 + * @library /testlibrary /testlibrary/whitebox + * @build TestHumongousCodeCacheRoots + * @run main ClassFileInstaller sun.hotspot.WhiteBox + * @summary Humongous objects may have references from the code cache + * @run main TestHumongousCodeCacheRoots +*/ + +import com.oracle.java.testlibrary.*; +import sun.hotspot.WhiteBox; + +import java.util.ArrayList; +import java.util.Arrays; + +class TestHumongousCodeCacheRootsHelper { + + static final int n = 1000000; + static final int[] AA = new int[n]; + static final int[] BB = new int[n]; + + public static void main(String args[]) throws Exception { + // do some work so that the compiler compiles this method, inlining the + // reference to the integer array (which is a humonguous object) into + // the code cache. + for(int i = 0; i < n; i++) { + AA[i] = 0; + BB[i] = 0; + } + // trigger a GC that checks that the verification code allows humongous + // objects with code cache roots; objects should be all live here. + System.gc(); + + // deoptimize everyhing: this should make all compiled code zombies. + WhiteBox wb = WhiteBox.getWhiteBox(); + wb.deoptimizeAll(); + + // trigger a GC that checks that the verification code allows humongous + // objects with code cache roots; objects should be all live here. + System.gc(); + + // wait a little for the code cache sweeper to try to clean up zombie nmethods + // and unregister the code roots. + try { Thread.sleep(5000); } catch (InterruptedException ex) { } + + // do some work on the arrays to make sure that they need to be live after the GCs + for(int i = 0; i < n; i++) { + AA[i] = 1; + BB[i] = 10; + } + + System.out.println(); + } +} + +public class TestHumongousCodeCacheRoots { + + /** + * Executes a class in a new VM process with the given parameters. + * @param vmargs Arguments to the VM to run + * @param classname Name of the class to run + * @param arguments Arguments to the class + * @param useTestDotJavaDotOpts Use test.java.opts as part of the VM argument string + * @return The OutputAnalyzer with the results for the invocation. + */ + public static OutputAnalyzer runWhiteBoxTest(String[] vmargs, String classname, String[] arguments, boolean useTestDotJavaDotOpts) throws Exception { + ArrayList finalargs = new ArrayList(); + + String[] whiteboxOpts = new String[] { + "-Xbootclasspath/a:.", + "-XX:+UnlockDiagnosticVMOptions", "-XX:+WhiteBoxAPI", + "-cp", System.getProperty("java.class.path"), + }; + + if (useTestDotJavaDotOpts) { + // System.getProperty("test.java.opts") is '' if no options is set, + // we need to skip such a result + String[] externalVMOpts = new String[0]; + if (System.getProperty("test.java.opts") != null && System.getProperty("test.java.opts").length() != 0) { + externalVMOpts = System.getProperty("test.java.opts").split(" "); + } + finalargs.addAll(Arrays.asList(externalVMOpts)); + } + + finalargs.addAll(Arrays.asList(vmargs)); + finalargs.addAll(Arrays.asList(whiteboxOpts)); + finalargs.add(classname); + finalargs.addAll(Arrays.asList(arguments)); + + ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(finalargs.toArray(new String[0])); + OutputAnalyzer output = new OutputAnalyzer(pb.start()); + output.shouldHaveExitValue(0); + + return output; + } + + public static void runTest(String compiler, String[] other) throws Exception { + ArrayList joined = new ArrayList(); + joined.add(compiler); + joined.addAll(Arrays.asList(other)); + runWhiteBoxTest(joined.toArray(new String[0]), TestHumongousCodeCacheRootsHelper.class.getName(), + new String[] {}, false); + } + + public static void main(String[] args) throws Exception { + final String[] baseArguments = new String[] { + "-XX:+UseG1GC", "-XX:G1HeapRegionSize=1M", "-Xmx100M", // make sure we get a humongous region + "-XX:+UnlockDiagnosticVMOptions", + "-XX:InitiatingHeapOccupancyPercent=1", // strong code root marking + "-XX:+G1VerifyHeapRegionCodeRoots", "-XX:+VerifyAfterGC", // make sure that verification is run + "-XX:NmethodSweepFraction=1", "-XX:NmethodSweepCheckInterval=1", // make the code cache sweep more predictable + }; + runTest("-client", baseArguments); + runTest("-server", baseArguments); + } +} +