1 /* 2 * Copyright (c) 2001, 2018, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "gc/parallel/mutableSpace.hpp" 27 #include "gc/shared/spaceDecorator.hpp" 28 #include "memory/iterator.inline.hpp" 29 #include "memory/universe.hpp" 30 #include "oops/oop.inline.hpp" 31 #include "runtime/atomic.hpp" 32 #include "runtime/safepoint.hpp" 33 #include "runtime/thread.hpp" 34 #include "utilities/align.hpp" 35 #include "utilities/macros.hpp" 36 37 MutableSpace::MutableSpace(size_t alignment): ImmutableSpace(), _alignment(alignment), _top(NULL) { 38 assert(MutableSpace::alignment() % os::vm_page_size() == 0, 39 "Space should be aligned"); 40 _mangler = new MutableSpaceMangler(this); 41 } 42 43 MutableSpace::~MutableSpace() { 44 delete _mangler; 45 } 46 47 void MutableSpace::numa_setup_pages(MemRegion mr, bool clear_space) { 48 if (!mr.is_empty()) { 49 size_t page_size = UseLargePages ? alignment() : os::vm_page_size(); 50 HeapWord *start = align_up(mr.start(), page_size); 51 HeapWord *end = align_down(mr.end(), page_size); 52 if (end > start) { 53 size_t size = pointer_delta(end, start, sizeof(char)); 54 if (clear_space) { 55 // Prefer page reallocation to migration. 56 os::free_memory((char*)start, size, page_size); 57 } 58 os::numa_make_global((char*)start, size); 59 } 60 } 61 } 62 63 void MutableSpace::pretouch_pages(MemRegion mr) { 64 os::pretouch_memory(mr.start(), mr.end()); 65 } 66 67 void MutableSpace::initialize(MemRegion mr, 68 bool clear_space, 69 bool mangle_space, 70 bool setup_pages) { 71 72 assert(Universe::on_page_boundary(mr.start()) && Universe::on_page_boundary(mr.end()), 73 "invalid space boundaries"); 74 75 if (setup_pages && (UseNUMA || AlwaysPreTouch)) { 76 // The space may move left and right or expand/shrink. 77 // We'd like to enforce the desired page placement. 78 MemRegion head, tail; 79 if (last_setup_region().is_empty()) { 80 // If it's the first initialization don't limit the amount of work. 81 head = mr; 82 tail = MemRegion(mr.end(), mr.end()); 83 } else { 84 // Is there an intersection with the address space? 85 MemRegion intersection = last_setup_region().intersection(mr); 86 if (intersection.is_empty()) { 87 intersection = MemRegion(mr.end(), mr.end()); 88 } 89 // All the sizes below are in words. 90 size_t head_size = 0, tail_size = 0; 91 if (mr.start() <= intersection.start()) { 92 head_size = pointer_delta(intersection.start(), mr.start()); 93 } 94 if(intersection.end() <= mr.end()) { 95 tail_size = pointer_delta(mr.end(), intersection.end()); 96 } 97 // Limit the amount of page manipulation if necessary. 98 if (NUMASpaceResizeRate > 0 && !AlwaysPreTouch) { 99 const size_t change_size = head_size + tail_size; 100 const float setup_rate_words = NUMASpaceResizeRate >> LogBytesPerWord; 101 head_size = MIN2((size_t)(setup_rate_words * head_size / change_size), 102 head_size); 103 tail_size = MIN2((size_t)(setup_rate_words * tail_size / change_size), 104 tail_size); 105 } 106 head = MemRegion(intersection.start() - head_size, intersection.start()); 107 tail = MemRegion(intersection.end(), intersection.end() + tail_size); 108 } 109 assert(mr.contains(head) && mr.contains(tail), "Sanity"); 110 111 if (UseNUMA) { 112 numa_setup_pages(head, clear_space); 113 numa_setup_pages(tail, clear_space); 114 } 115 116 if (AlwaysPreTouch) { 117 pretouch_pages(head); 118 pretouch_pages(tail); 119 } 120 121 // Remember where we stopped so that we can continue later. 122 set_last_setup_region(MemRegion(head.start(), tail.end())); 123 } 124 125 set_bottom(mr.start()); 126 set_end(mr.end()); 127 128 if (clear_space) { 129 clear(mangle_space); 130 } 131 } 132 133 void MutableSpace::clear(bool mangle_space) { 134 set_top(bottom()); 135 if (ZapUnusedHeapArea && mangle_space) { 136 mangle_unused_area(); 137 } 138 } 139 140 #ifndef PRODUCT 141 void MutableSpace::check_mangled_unused_area(HeapWord* limit) { 142 mangler()->check_mangled_unused_area(limit); 143 } 144 145 void MutableSpace::check_mangled_unused_area_complete() { 146 mangler()->check_mangled_unused_area_complete(); 147 } 148 149 // Mangle only the unused space that has not previously 150 // been mangled and that has not been allocated since being 151 // mangled. 152 void MutableSpace::mangle_unused_area() { 153 mangler()->mangle_unused_area(); 154 } 155 156 void MutableSpace::mangle_unused_area_complete() { 157 mangler()->mangle_unused_area_complete(); 158 } 159 160 void MutableSpace::mangle_region(MemRegion mr) { 161 SpaceMangler::mangle_region(mr); 162 } 163 164 void MutableSpace::set_top_for_allocations(HeapWord* v) { 165 mangler()->set_top_for_allocations(v); 166 } 167 168 void MutableSpace::set_top_for_allocations() { 169 mangler()->set_top_for_allocations(top()); 170 } 171 #endif 172 173 // This version requires locking. */ 174 HeapWord* MutableSpace::allocate(size_t size) { 175 assert(Heap_lock->owned_by_self() || 176 (SafepointSynchronize::is_at_safepoint() && 177 Thread::current()->is_VM_thread()), 178 "not locked"); 179 HeapWord* obj = top(); 180 if (pointer_delta(end(), obj) >= size) { 181 HeapWord* new_top = obj + size; 182 set_top(new_top); 183 assert(is_object_aligned(obj) && is_object_aligned(new_top), 184 "checking alignment"); 185 return obj; 186 } else { 187 return NULL; 188 } 189 } 190 191 // This version is lock-free. 192 HeapWord* MutableSpace::cas_allocate(size_t size) { 193 do { 194 HeapWord* obj = top(); 195 if (pointer_delta(end(), obj) >= size) { 196 HeapWord* new_top = obj + size; 197 HeapWord* result = Atomic::cmpxchg(new_top, top_addr(), obj); 198 // result can be one of two: 199 // the old top value: the exchange succeeded 200 // otherwise: the new value of the top is returned. 201 if (result != obj) { 202 continue; // another thread beat us to the allocation, try again 203 } 204 assert(is_object_aligned(obj) && is_object_aligned(new_top), 205 "checking alignment"); 206 return obj; 207 } else { 208 return NULL; 209 } 210 } while (true); 211 } 212 213 // Try to deallocate previous allocation. Returns true upon success. 214 bool MutableSpace::cas_deallocate(HeapWord *obj, size_t size) { 215 HeapWord* expected_top = obj + size; 216 return Atomic::cmpxchg(obj, top_addr(), expected_top) == expected_top; 217 } 218 219 void MutableSpace::oop_iterate(OopIterateClosure* cl) { 220 HeapWord* obj_addr = bottom(); 221 HeapWord* t = top(); 222 // Could call objects iterate, but this is easier. 223 while (obj_addr < t) { 224 obj_addr += oop(obj_addr)->oop_iterate_size(cl); 225 } 226 } 227 228 void MutableSpace::object_iterate(ObjectClosure* cl) { 229 HeapWord* p = bottom(); 230 while (p < top()) { 231 cl->do_object(oop(p)); 232 p += oop(p)->size(); 233 } 234 } 235 236 void MutableSpace::print_short() const { print_short_on(tty); } 237 void MutableSpace::print_short_on( outputStream* st) const { 238 st->print(" space " SIZE_FORMAT "K, %d%% used", capacity_in_bytes() / K, 239 (int) ((double) used_in_bytes() * 100 / capacity_in_bytes())); 240 } 241 242 void MutableSpace::print() const { print_on(tty); } 243 void MutableSpace::print_on(outputStream* st) const { 244 MutableSpace::print_short_on(st); 245 st->print_cr(" [" INTPTR_FORMAT "," INTPTR_FORMAT "," INTPTR_FORMAT ")", 246 p2i(bottom()), p2i(top()), p2i(end())); 247 } 248 249 void MutableSpace::verify() { 250 HeapWord* p = bottom(); 251 HeapWord* t = top(); 252 HeapWord* prev_p = NULL; 253 while (p < t) { 254 oopDesc::verify(oop(p)); 255 prev_p = p; 256 p += oop(p)->size(); 257 } 258 guarantee(p == top(), "end of last object must match end of space"); 259 }