1 /* 2 * Copyright (c) 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/psFileBackedVirtualspace.hpp" 27 #include "memory/virtualspace.hpp" 28 #include "runtime/os.hpp" 29 30 PSFileBackedVirtualSpace::PSFileBackedVirtualSpace(ReservedSpace rs, size_t alignment, const char* path) : PSVirtualSpace(rs, alignment) { 31 assert(!rs.special(), "ReservedSpace passed to PSFileBackedVirtualSpace cannot be special"); 32 33 _mapping_succeeded = false; 34 _file_path = path; 35 _fd = os::create_file_for_heap(path); 36 if (_fd == -1) { 37 return; 38 } 39 // We map the reserved space to a file at initialization. 40 char* ret = os::replace_existing_mapping_with_file_mapping(rs.base(), rs.size(), _fd); 41 if (ret != rs.base()) { 42 return; 43 } 44 // _mapping_succeeded is false if we return before this point. 45 // expand calls later check value of this flag and return error if it is false. 46 _mapping_succeeded = true; 47 _special = true; 48 } 49 50 PSFileBackedVirtualSpace::PSFileBackedVirtualSpace(ReservedSpace rs, const char* path) { 51 PSFileBackedVirtualSpace(rs, os::vm_page_size(), path); 52 } 53 54 bool PSFileBackedVirtualSpace::expand_by(size_t bytes) { 55 assert(special(), "_special should always be true for PSFileBackedVirtualSpace"); 56 57 // if mapping did not succeed during intialization return false 58 if (!_mapping_succeeded) { 59 return false; 60 } 61 return PSVirtualSpace::expand_by(bytes); 62 63 } 64 65 bool PSFileBackedVirtualSpace::shrink_by(size_t bytes) { 66 assert(special(), "_special should always be true for PSFileBackedVirtualSpace"); 67 return PSVirtualSpace::shrink_by(bytes); 68 } 69 70 size_t PSFileBackedVirtualSpace::expand_into(PSVirtualSpace* space, size_t bytes) { 71 // not supported. Since doing this will change page mapping which will lead to large TLB penalties. 72 assert(false, "expand_into() should not be called for PSFileBackedVirtualSpace"); 73 return 0; 74 } 75 76 void PSFileBackedVirtualSpace::release() { 77 os::close(_fd); 78 _fd = -1; 79 _file_path = NULL; 80 81 PSVirtualSpace::release(); 82 }