1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/share/vm/oops/markOop.inline.hpp Sat Dec 01 00:00:00 2007 +0000
1.3 @@ -0,0 +1,80 @@
1.4 +/*
1.5 + * Copyright 2006 Sun Microsystems, Inc. All Rights Reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation.
1.11 + *
1.12 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.13 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.14 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.15 + * version 2 for more details (a copy is included in the LICENSE file that
1.16 + * accompanied this code).
1.17 + *
1.18 + * You should have received a copy of the GNU General Public License version
1.19 + * 2 along with this work; if not, write to the Free Software Foundation,
1.20 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.21 + *
1.22 + * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
1.23 + * CA 95054 USA or visit www.sun.com if you need additional information or
1.24 + * have any questions.
1.25 + *
1.26 + */
1.27 +
1.28 +// Should this header be preserved during GC?
1.29 +inline bool markOopDesc::must_be_preserved_with_bias(oop obj_containing_mark) const {
1.30 + assert(UseBiasedLocking, "unexpected");
1.31 + if (has_bias_pattern()) {
1.32 + // Will reset bias at end of collection
1.33 + // Mark words of biased and currently locked objects are preserved separately
1.34 + return false;
1.35 + }
1.36 + markOop prototype_header = prototype_for_object(obj_containing_mark);
1.37 + if (prototype_header->has_bias_pattern()) {
1.38 + // Individual instance which has its bias revoked; must return
1.39 + // true for correctness
1.40 + return true;
1.41 + }
1.42 + return (!is_unlocked() || !has_no_hash());
1.43 +}
1.44 +
1.45 +// Should this header (including its age bits) be preserved in the
1.46 +// case of a promotion failure during scavenge?
1.47 +inline bool markOopDesc::must_be_preserved_with_bias_for_promotion_failure(oop obj_containing_mark) const {
1.48 + assert(UseBiasedLocking, "unexpected");
1.49 + // We don't explicitly save off the mark words of biased and
1.50 + // currently-locked objects during scavenges, so if during a
1.51 + // promotion failure we encounter either a biased mark word or a
1.52 + // klass which still has a biasable prototype header, we have to
1.53 + // preserve the mark word. This results in oversaving, but promotion
1.54 + // failures are rare, and this avoids adding more complex logic to
1.55 + // the scavengers to call new variants of
1.56 + // BiasedLocking::preserve_marks() / restore_marks() in the middle
1.57 + // of a scavenge when a promotion failure has first been detected.
1.58 + if (has_bias_pattern() ||
1.59 + prototype_for_object(obj_containing_mark)->has_bias_pattern()) {
1.60 + return true;
1.61 + }
1.62 + return (this != prototype());
1.63 +}
1.64 +
1.65 +// Should this header (including its age bits) be preserved in the
1.66 +// case of a scavenge in which CMS is the old generation?
1.67 +inline bool markOopDesc::must_be_preserved_with_bias_for_cms_scavenge(klassOop klass_of_obj_containing_mark) const {
1.68 + assert(UseBiasedLocking, "unexpected");
1.69 + // CMS scavenges preserve mark words in similar fashion to promotion failures; see above
1.70 + if (has_bias_pattern() ||
1.71 + klass_of_obj_containing_mark->klass_part()->prototype_header()->has_bias_pattern()) {
1.72 + return true;
1.73 + }
1.74 + return (this != prototype());
1.75 +}
1.76 +
1.77 +inline markOop markOopDesc::prototype_for_object(oop obj) {
1.78 +#ifdef ASSERT
1.79 + markOop prototype_header = obj->klass()->klass_part()->prototype_header();
1.80 + assert(prototype_header == prototype() || prototype_header->has_bias_pattern(), "corrupt prototype header");
1.81 +#endif
1.82 + return obj->klass()->klass_part()->prototype_header();
1.83 +}
