1 /* 2 * Copyright (c) 2001, 2015, 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 "runtime/atomic.inline.hpp" 27 #include "utilities/macros.hpp" 28 #if INCLUDE_ALL_GCS 29 #include "gc_implementation/shared/mutableSpace.hpp" 30 #include "gc_implementation/shared/spaceDecorator.hpp" 31 #include "oops/oop.inline.hpp" 32 #include "runtime/safepoint.hpp" 33 #include "runtime/thread.hpp" 34 #endif // INCLUDE_ALL_GCS 35 36 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC 37 38 MutableSpace::MutableSpace(size_t alignment): ImmutableSpace(), _top(NULL), _alignment(alignment) { 39 assert(MutableSpace::alignment() % os::vm_page_size() == 0, 40 "Space should be aligned"); 41 _mangler = new MutableSpaceMangler(this); 42 } 43 44 MutableSpace::~MutableSpace() { 45 delete _mangler; 46 } 47 48 void MutableSpace::numa_setup_pages(MemRegion mr, bool clear_space) { 49 if (!mr.is_empty()) { 50 size_t page_size = UseLargePages ? alignment() : os::vm_page_size(); 51 HeapWord *start = (HeapWord*)round_to((intptr_t) mr.start(), page_size); 52 HeapWord *end = (HeapWord*)round_down((intptr_t) mr.end(), page_size); 53 if (end > start) { 54 size_t size = pointer_delta(end, start, sizeof(char)); 55 if (clear_space) { 56 // Prefer page reallocation to migration. 57 os::free_memory((char*)start, size, page_size); 58 } 59 os::numa_make_global((char*)start, size); 60 } 61 } 62 } 63 64 void MutableSpace::pretouch_pages(MemRegion mr) { 65 os::pretouch_memory((char*)mr.start(), (char*)mr.end()); 66 } 67 68 void MutableSpace::initialize(MemRegion mr, 69 bool clear_space, 70 bool mangle_space, 71 bool setup_pages) { 72 73 assert(Universe::on_page_boundary(mr.start()) && Universe::on_page_boundary(mr.end()), 74 "invalid space boundaries"); 75 76 if (setup_pages && (UseNUMA || AlwaysPreTouch)) { 77 // The space may move left and right or expand/shrink. 78 // We'd like to enforce the desired page placement. 79 MemRegion head, tail; 80 if (last_setup_region().is_empty()) { 81 // If it's the first initialization don't limit the amount of work. 82 head = mr; 83 tail = MemRegion(mr.end(), mr.end()); 84 } else { 85 // Is there an intersection with the address space? 86 MemRegion intersection = last_setup_region().intersection(mr); 87 if (intersection.is_empty()) { 88 intersection = MemRegion(mr.end(), mr.end()); 89 } 90 // All the sizes below are in words. 91 size_t head_size = 0, tail_size = 0; 92 if (mr.start() <= intersection.start()) { 93 head_size = pointer_delta(intersection.start(), mr.start()); 94 } 95 if(intersection.end() <= mr.end()) { 96 tail_size = pointer_delta(mr.end(), intersection.end()); 97 } 98 // Limit the amount of page manipulation if necessary. 99 if (NUMASpaceResizeRate > 0 && !AlwaysPreTouch) { 100 const size_t change_size = head_size + tail_size; 101 const float setup_rate_words = NUMASpaceResizeRate >> LogBytesPerWord; 102 head_size = MIN2((size_t)(setup_rate_words * head_size / change_size), 103 head_size); 104 tail_size = MIN2((size_t)(setup_rate_words * tail_size / change_size), 105 tail_size); 106 } 107 head = MemRegion(intersection.start() - head_size, intersection.start()); 108 tail = MemRegion(intersection.end(), intersection.end() + tail_size); 109 } 110 assert(mr.contains(head) && mr.contains(tail), "Sanity"); 111 112 if (UseNUMA) { 113 numa_setup_pages(head, clear_space); 114 numa_setup_pages(tail, clear_space); 115 } 116 117 if (AlwaysPreTouch) { 118 pretouch_pages(head); 119 pretouch_pages(tail); 120 } 121 122 // Remember where we stopped so that we can continue later. 123 set_last_setup_region(MemRegion(head.start(), tail.end())); 124 } 125 126 set_bottom(mr.start()); 127 set_end(mr.end()); 128 129 if (clear_space) { 130 clear(mangle_space); 131 } 132 } 133 134 void MutableSpace::clear(bool mangle_space) { 135 set_top(bottom()); 136 if (ZapUnusedHeapArea && mangle_space) { 137 mangle_unused_area(); 138 } 139 } 140 141 #ifndef PRODUCT 142 void MutableSpace::check_mangled_unused_area(HeapWord* limit) { 143 mangler()->check_mangled_unused_area(limit); 144 } 145 146 void MutableSpace::check_mangled_unused_area_complete() { 147 mangler()->check_mangled_unused_area_complete(); 148 } 149 150 // Mangle only the unused space that has not previously 151 // been mangled and that has not been allocated since being 152 // mangled. 153 void MutableSpace::mangle_unused_area() { 154 mangler()->mangle_unused_area(); 155 } 156 157 void MutableSpace::mangle_unused_area_complete() { 158 mangler()->mangle_unused_area_complete(); 159 } 160 161 void MutableSpace::mangle_region(MemRegion mr) { 162 SpaceMangler::mangle_region(mr); 163 } 164 165 void MutableSpace::set_top_for_allocations(HeapWord* v) { 166 mangler()->set_top_for_allocations(v); 167 } 168 169 void MutableSpace::set_top_for_allocations() { 170 mangler()->set_top_for_allocations(top()); 171 } 172 #endif 173 174 // This version requires locking. */ 175 HeapWord* MutableSpace::allocate(size_t size) { 176 assert(Heap_lock->owned_by_self() || 177 (SafepointSynchronize::is_at_safepoint() && 178 Thread::current()->is_VM_thread()), 179 "not locked"); 180 HeapWord* obj = top(); 181 if (pointer_delta(end(), obj) >= size) { 182 HeapWord* new_top = obj + size; 183 set_top(new_top); 184 assert(is_object_aligned((intptr_t)obj) && is_object_aligned((intptr_t)new_top), 185 "checking alignment"); 186 return obj; 187 } else { 188 return NULL; 189 } 190 } 191 192 // This version is lock-free. 193 HeapWord* MutableSpace::cas_allocate(size_t size) { 194 do { 195 HeapWord* obj = top(); 196 if (pointer_delta(end(), obj) >= size) { 197 HeapWord* new_top = obj + size; 198 HeapWord* result = (HeapWord*)Atomic::cmpxchg_ptr(new_top, top_addr(), obj); 199 // result can be one of two: 200 // the old top value: the exchange succeeded 201 // otherwise: the new value of the top is returned. 202 if (result != obj) { 203 continue; // another thread beat us to the allocation, try again 204 } 205 assert(is_object_aligned((intptr_t)obj) && is_object_aligned((intptr_t)new_top), 206 "checking alignment"); 207 return obj; 208 } else { 209 return NULL; 210 } 211 } while (true); 212 } 213 214 // Try to deallocate previous allocation. Returns true upon success. 215 bool MutableSpace::cas_deallocate(HeapWord *obj, size_t size) { 216 HeapWord* expected_top = obj + size; 217 return (HeapWord*)Atomic::cmpxchg_ptr(obj, top_addr(), expected_top) == expected_top; 218 } 219 220 void MutableSpace::oop_iterate(ExtendedOopClosure* cl) { 221 HeapWord* obj_addr = bottom(); 222 HeapWord* t = top(); 223 // Could call objects iterate, but this is easier. 224 while (obj_addr < t) { 225 obj_addr += oop(obj_addr)->oop_iterate(cl); 226 } 227 } 228 229 void MutableSpace::oop_iterate_no_header(OopClosure* cl) { 230 HeapWord* obj_addr = bottom(); 231 HeapWord* t = top(); 232 // Could call objects iterate, but this is easier. 233 while (obj_addr < t) { 234 obj_addr += oop(obj_addr)->oop_iterate_no_header(cl); 235 } 236 } 237 238 void MutableSpace::object_iterate(ObjectClosure* cl) { 239 HeapWord* p = bottom(); 240 while (p < top()) { 241 cl->do_object(oop(p)); 242 p += oop(p)->size(); 243 } 244 } 245 246 void MutableSpace::print_short() const { print_short_on(tty); } 247 void MutableSpace::print_short_on( outputStream* st) const { 248 st->print(" space " SIZE_FORMAT "K, %d%% used", capacity_in_bytes() / K, 249 (int) ((double) used_in_bytes() * 100 / capacity_in_bytes())); 250 } 251 252 void MutableSpace::print() const { print_on(tty); } 253 void MutableSpace::print_on(outputStream* st) const { 254 MutableSpace::print_short_on(st); 255 st->print_cr(" [" INTPTR_FORMAT "," INTPTR_FORMAT "," INTPTR_FORMAT ")", 256 bottom(), top(), end()); 257 } 258 259 void MutableSpace::verify() { 260 HeapWord* p = bottom(); 261 HeapWord* t = top(); 262 HeapWord* prev_p = NULL; 263 while (p < t) { 264 oop(p)->verify(); 265 prev_p = p; 266 p += oop(p)->size(); 267 } 268 guarantee(p == top(), "end of last object must match end of space"); 269 }