1 /* 2 * Copyright (c) 2018, 2019, 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 #ifndef SHARE_UTILITIES_GLOBALCOUNTER_INLINE_HPP 26 #define SHARE_UTILITIES_GLOBALCOUNTER_INLINE_HPP 27 28 #include "runtime/atomic.hpp" 29 #include "runtime/orderAccess.hpp" 30 #include "runtime/thread.inline.hpp" 31 #include "utilities/globalCounter.hpp" 32 33 inline GlobalCounter::CSContext 34 GlobalCounter::critical_section_begin(Thread *thread) { 35 assert(thread == Thread::current(), "must be current thread"); 36 uintx old_cnt = Atomic::load(thread->get_rcu_counter()); 37 // Retain the old counter value if already active, e.g. nested. 38 // Otherwise, set the counter to the current version + active bit. 39 uintx new_cnt = old_cnt; 40 if ((new_cnt & COUNTER_ACTIVE) == 0) { 41 new_cnt = Atomic::load(&_global_counter._counter) | COUNTER_ACTIVE; 42 } 43 Atomic::release_store_fence(thread->get_rcu_counter(), new_cnt); 44 return static_cast<CSContext>(old_cnt); 45 } 46 47 inline void 48 GlobalCounter::critical_section_end(Thread *thread, CSContext context) { 49 assert(thread == Thread::current(), "must be current thread"); 50 assert((*thread->get_rcu_counter() & COUNTER_ACTIVE) == COUNTER_ACTIVE, "must be in critical section"); 51 // Restore the counter value from before the associated begin. 52 Atomic::release_store(thread->get_rcu_counter(), 53 static_cast<uintx>(context)); 54 } 55 56 class GlobalCounter::CriticalSection { 57 private: 58 Thread* _thread; 59 CSContext _context; 60 public: 61 inline CriticalSection(Thread* thread) : 62 _thread(thread), 63 _context(GlobalCounter::critical_section_begin(_thread)) 64 {} 65 66 inline ~CriticalSection() { 67 GlobalCounter::critical_section_end(_thread, _context); 68 } 69 }; 70 71 #endif // SHARE_UTILITIES_GLOBALCOUNTER_INLINE_HPP