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src/share/vm/gc_implementation/shared/suspendibleThreadSet.hpp@9f28a4cac6d9 (annotated)
src/share/vm/gc_implementation/shared/suspendibleThreadSet.hpp
Wed, 31 Jul 2019 14:28:51 -0400
- author
- kbarrett
- date
- Wed, 31 Jul 2019 14:28:51 -0400
- changeset 9787
- 9f28a4cac6d9
- parent 6906
- 581e70386ec9
- permissions
- -rw-r--r--
8048556: Unnecessary GCLocker-initiated young GCs
Summary: Fixed recognition of unnecessary GCLocker collections.
Reviewed-by: pliden, tschatzl
Contributed-by: johnc@azul.com
| pliden@6906 | 1 | /* |
| pliden@6906 | 2 | * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved. |
| pliden@6906 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| pliden@6906 | 4 | * |
| pliden@6906 | 5 | * This code is free software; you can redistribute it and/or modify it |
| pliden@6906 | 6 | * under the terms of the GNU General Public License version 2 only, as |
| pliden@6906 | 7 | * published by the Free Software Foundation. |
| pliden@6906 | 8 | * |
| pliden@6906 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| pliden@6906 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| pliden@6906 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| pliden@6906 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
| pliden@6906 | 13 | * accompanied this code). |
| pliden@6906 | 14 | * |
| pliden@6906 | 15 | * You should have received a copy of the GNU General Public License version |
| pliden@6906 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
| pliden@6906 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| pliden@6906 | 18 | * |
| pliden@6906 | 19 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| pliden@6906 | 20 | * or visit www.oracle.com if you need additional information or have any |
| pliden@6906 | 21 | * questions. |
| pliden@6906 | 22 | * |
| pliden@6906 | 23 | */ |
| pliden@6906 | 24 | |
| pliden@6906 | 25 | #ifndef SHARE_VM_GC_IMPLEMENTATION_SHARED_SUSPENDIBLETHREADSET_HPP |
| pliden@6906 | 26 | #define SHARE_VM_GC_IMPLEMENTATION_SHARED_SUSPENDIBLETHREADSET_HPP |
| pliden@6906 | 27 | |
| pliden@6906 | 28 | #include "memory/allocation.hpp" |
| pliden@6906 | 29 | |
| pliden@6906 | 30 | // A SuspendibleThreadSet is a set of threads that can be suspended. |
| pliden@6906 | 31 | // A thread can join and later leave the set, and periodically yield. |
| pliden@6906 | 32 | // If some thread (not in the set) requests, via synchronize(), that |
| pliden@6906 | 33 | // the threads be suspended, then the requesting thread is blocked |
| pliden@6906 | 34 | // until all the threads in the set have yielded or left the set. Threads |
| pliden@6906 | 35 | // may not enter the set when an attempted suspension is in progress. The |
| pliden@6906 | 36 | // suspending thread later calls desynchronize(), allowing the suspended |
| pliden@6906 | 37 | // threads to continue. |
| pliden@6906 | 38 | class SuspendibleThreadSet : public AllStatic { |
| pliden@6906 | 39 | private: |
| pliden@6906 | 40 | static uint _nthreads; |
| pliden@6906 | 41 | static uint _nthreads_stopped; |
| pliden@6906 | 42 | static bool _suspend_all; |
| pliden@6906 | 43 | static double _suspend_all_start; |
| pliden@6906 | 44 | |
| pliden@6906 | 45 | public: |
| pliden@6906 | 46 | // Add the current thread to the set. May block if a suspension is in progress. |
| pliden@6906 | 47 | static void join(); |
| pliden@6906 | 48 | |
| pliden@6906 | 49 | // Removes the current thread from the set. |
| pliden@6906 | 50 | static void leave(); |
| pliden@6906 | 51 | |
| pliden@6906 | 52 | // Returns true if an suspension is in progress. |
| pliden@6906 | 53 | static bool should_yield() { return _suspend_all; } |
| pliden@6906 | 54 | |
| pliden@6906 | 55 | // Suspends the current thread if a suspension is in progress. |
| pliden@6906 | 56 | static void yield(); |
| pliden@6906 | 57 | |
| pliden@6906 | 58 | // Returns when all threads in the set are suspended. |
| pliden@6906 | 59 | static void synchronize(); |
| pliden@6906 | 60 | |
| pliden@6906 | 61 | // Resumes all suspended threads in the set. |
| pliden@6906 | 62 | static void desynchronize(); |
| pliden@6906 | 63 | }; |
| pliden@6906 | 64 | |
| pliden@6906 | 65 | class SuspendibleThreadSetJoiner : public StackObj { |
| pliden@6906 | 66 | public: |
| pliden@6906 | 67 | SuspendibleThreadSetJoiner() { |
| pliden@6906 | 68 | SuspendibleThreadSet::join(); |
| pliden@6906 | 69 | } |
| pliden@6906 | 70 | |
| pliden@6906 | 71 | ~SuspendibleThreadSetJoiner() { |
| pliden@6906 | 72 | SuspendibleThreadSet::leave(); |
| pliden@6906 | 73 | } |
| pliden@6906 | 74 | |
| pliden@6906 | 75 | bool should_yield() { |
| pliden@6906 | 76 | return SuspendibleThreadSet::should_yield(); |
| pliden@6906 | 77 | } |
| pliden@6906 | 78 | |
| pliden@6906 | 79 | void yield() { |
| pliden@6906 | 80 | SuspendibleThreadSet::yield(); |
| pliden@6906 | 81 | } |
| pliden@6906 | 82 | }; |
| pliden@6906 | 83 | |
| pliden@6906 | 84 | #endif // SHARE_VM_GC_IMPLEMENTATION_SHARED_SUSPENDIBLETHREADSET_HPP |
