Mercurial > jdk8-mips64-public > hotspot / annotate
src/share/vm/memory/memRegion.cpp@5134fa1cfe63 (annotated)
src/share/vm/memory/memRegion.cpp
Thu, 24 Mar 2011 15:47:01 -0700
- author
- ysr
- date
- Thu, 24 Mar 2011 15:47:01 -0700
- changeset 2710
- 5134fa1cfe63
- parent 2314
- f95d63e2154a
- child 5103
- f9be75d21404
- permissions
- -rw-r--r--
7029036: Card-table verification hangs with all framework collectors, except G1, even before the first GC
Summary: When verifying clean card ranges, use memory-range-bounded iteration over oops of objects overlapping that range, thus avoiding the otherwise quadratic worst-case cost of scanning large object arrays.
Reviewed-by: jmasa, jwilhelm, tonyp
| duke@435 | 1 | /* |
| stefank@2314 | 2 | * Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved. |
| duke@435 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| duke@435 | 4 | * |
| duke@435 | 5 | * This code is free software; you can redistribute it and/or modify it |
| duke@435 | 6 | * under the terms of the GNU General Public License version 2 only, as |
| duke@435 | 7 | * published by the Free Software Foundation. |
| duke@435 | 8 | * |
| duke@435 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| duke@435 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| duke@435 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| duke@435 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
| duke@435 | 13 | * accompanied this code). |
| duke@435 | 14 | * |
| duke@435 | 15 | * You should have received a copy of the GNU General Public License version |
| duke@435 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
| duke@435 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| duke@435 | 18 | * |
| trims@1907 | 19 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| trims@1907 | 20 | * or visit www.oracle.com if you need additional information or have any |
| trims@1907 | 21 | * questions. |
| duke@435 | 22 | * |
| duke@435 | 23 | */ |
| duke@435 | 24 | |
| stefank@2314 | 25 | #include "precompiled.hpp" |
| stefank@2314 | 26 | #include "memory/memRegion.hpp" |
| stefank@2314 | 27 | #include "runtime/globals.hpp" |
| stefank@2314 | 28 | |
| duke@435 | 29 | // A very simple data structure representing a contigous word-aligned |
| duke@435 | 30 | // region of address space. |
| duke@435 | 31 | |
| duke@435 | 32 | MemRegion MemRegion::intersection(const MemRegion mr2) const { |
| duke@435 | 33 | MemRegion res; |
| duke@435 | 34 | HeapWord* res_start = MAX2(start(), mr2.start()); |
| duke@435 | 35 | HeapWord* res_end = MIN2(end(), mr2.end()); |
| duke@435 | 36 | if (res_start < res_end) { |
| duke@435 | 37 | res.set_start(res_start); |
| duke@435 | 38 | res.set_end(res_end); |
| duke@435 | 39 | } |
| duke@435 | 40 | return res; |
| duke@435 | 41 | } |
| duke@435 | 42 | |
| duke@435 | 43 | MemRegion MemRegion::_union(const MemRegion mr2) const { |
| duke@435 | 44 | // If one region is empty, return the other |
| duke@435 | 45 | if (is_empty()) return mr2; |
| duke@435 | 46 | if (mr2.is_empty()) return MemRegion(start(), end()); |
| duke@435 | 47 | |
| duke@435 | 48 | // Otherwise, regions must overlap or be adjacent |
| duke@435 | 49 | assert(((start() <= mr2.start()) && (end() >= mr2.start())) || |
| duke@435 | 50 | ((mr2.start() <= start()) && (mr2.end() >= start())), |
| duke@435 | 51 | "non-adjacent or overlapping regions"); |
| duke@435 | 52 | MemRegion res; |
| duke@435 | 53 | HeapWord* res_start = MIN2(start(), mr2.start()); |
| duke@435 | 54 | HeapWord* res_end = MAX2(end(), mr2.end()); |
| duke@435 | 55 | res.set_start(res_start); |
| duke@435 | 56 | res.set_end(res_end); |
| duke@435 | 57 | return res; |
| duke@435 | 58 | } |
| duke@435 | 59 | |
| duke@435 | 60 | MemRegion MemRegion::minus(const MemRegion mr2) const { |
| duke@435 | 61 | // There seem to be 6 cases: |
| duke@435 | 62 | // |this MemRegion| |
| duke@435 | 63 | // |strictly below| |
| duke@435 | 64 | // |overlap beginning| |
| duke@435 | 65 | // |interior| |
| duke@435 | 66 | // |overlap ending| |
| duke@435 | 67 | // |strictly above| |
| duke@435 | 68 | // |completely overlapping| |
| duke@435 | 69 | // We can't deal with an interior case because it would |
| duke@435 | 70 | // produce two disjoint regions as a result. |
| duke@435 | 71 | // We aren't trying to be optimal in the number of tests below, |
| duke@435 | 72 | // but the order is important to distinguish the strictly cases |
| duke@435 | 73 | // from the overlapping cases. |
| duke@435 | 74 | if (mr2.end() <= start()) { |
| duke@435 | 75 | // strictly below |
| duke@435 | 76 | return MemRegion(start(), end()); |
| duke@435 | 77 | } |
| duke@435 | 78 | if (mr2.start() <= start() && mr2.end() <= end()) { |
| duke@435 | 79 | // overlap beginning |
| duke@435 | 80 | return MemRegion(mr2.end(), end()); |
| duke@435 | 81 | } |
| duke@435 | 82 | if (mr2.start() >= end()) { |
| duke@435 | 83 | // strictly above |
| duke@435 | 84 | return MemRegion(start(), end()); |
| duke@435 | 85 | } |
| duke@435 | 86 | if (mr2.start() >= start() && mr2.end() >= end()) { |
| duke@435 | 87 | // overlap ending |
| duke@435 | 88 | return MemRegion(start(), mr2.start()); |
| duke@435 | 89 | } |
| duke@435 | 90 | if (mr2.start() <= start() && mr2.end() >= end()) { |
| duke@435 | 91 | // completely overlapping |
| duke@435 | 92 | return MemRegion(); |
| duke@435 | 93 | } |
| duke@435 | 94 | if (mr2.start() > start() && mr2.end() < end()) { |
| duke@435 | 95 | // interior |
| duke@435 | 96 | guarantee(false, "MemRegion::minus, but interior"); |
| duke@435 | 97 | return MemRegion(); |
| duke@435 | 98 | } |
| duke@435 | 99 | ShouldNotReachHere(); |
| duke@435 | 100 | return MemRegion(); |
| duke@435 | 101 | } |
