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 _file_path(path), _fd(-1), _mapping_succeeded(false) { 32 assert(!rs.special(), "ReservedSpace passed to PSFileBackedVirtualSpace cannot be special"); 33 } 34 35 bool PSFileBackedVirtualSpace::initialize() { 36 _fd = os::create_file_for_heap(_file_path); 37 if (_fd == -1) { 38 return false; 39 } 40 // We map the reserved space to a file at initialization. 41 char* ret = os::replace_existing_mapping_with_file_mapping(reserved_low_addr(), reserved_size(), _fd); 42 if (ret != reserved_low_addr()) { 43 return false; 44 } 45 // _mapping_succeeded is false if we return before this point. 46 // expand calls later check value of this flag and return error if it is false. 47 _mapping_succeeded = true; 48 _special = true; 49 return true; 50 } 51 52 PSFileBackedVirtualSpace::PSFileBackedVirtualSpace(ReservedSpace rs, const char* path) { 53 PSFileBackedVirtualSpace(rs, os::vm_page_size(), path); 54 } 55 56 bool PSFileBackedVirtualSpace::expand_by(size_t bytes) { 57 assert(special(), "Since entire space is committed at initialization, _special should always be true for PSFileBackedVirtualSpace"); 58 59 // if mapping did not succeed during intialization return false 60 if (!_mapping_succeeded) { 61 return false; 62 } 63 return PSVirtualSpace::expand_by(bytes); 64 65 } 66 67 bool PSFileBackedVirtualSpace::shrink_by(size_t bytes) { 68 assert(special(), "Since entire space is committed at initialization, _special should always be true for PSFileBackedVirtualSpace"); 69 return PSVirtualSpace::shrink_by(bytes); 70 } 71 72 size_t PSFileBackedVirtualSpace::expand_into(PSVirtualSpace* space, size_t bytes) { 73 // not supported. Since doing this will change page mapping which will lead to large TLB penalties. 74 assert(false, "expand_into() should not be called for PSFileBackedVirtualSpace"); 75 return 0; 76 } 77 78 void PSFileBackedVirtualSpace::release() { 79 os::close(_fd); 80 _fd = -1; 81 _file_path = NULL; 82 83 PSVirtualSpace::release(); 84 } 85