Thu, 24 May 2018 20:03:11 +0800
Increase MaxHeapSize for better performance on MIPS
aoqi@0 | 1 | /* |
aoqi@0 | 2 | * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved. |
aoqi@0 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
aoqi@0 | 4 | * |
aoqi@0 | 5 | * This code is free software; you can redistribute it and/or modify it |
aoqi@0 | 6 | * under the terms of the GNU General Public License version 2 only, as |
aoqi@0 | 7 | * published by the Free Software Foundation. |
aoqi@0 | 8 | * |
aoqi@0 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
aoqi@0 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
aoqi@0 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
aoqi@0 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
aoqi@0 | 13 | * accompanied this code). |
aoqi@0 | 14 | * |
aoqi@0 | 15 | * You should have received a copy of the GNU General Public License version |
aoqi@0 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
aoqi@0 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
aoqi@0 | 18 | * |
aoqi@0 | 19 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
aoqi@0 | 20 | * or visit www.oracle.com if you need additional information or have any |
aoqi@0 | 21 | * questions. |
aoqi@0 | 22 | * |
aoqi@0 | 23 | */ |
aoqi@0 | 24 | |
aoqi@0 | 25 | #ifndef SHARE_VM_RUNTIME_PARK_HPP |
aoqi@0 | 26 | #define SHARE_VM_RUNTIME_PARK_HPP |
aoqi@0 | 27 | |
aoqi@0 | 28 | #include "utilities/debug.hpp" |
aoqi@0 | 29 | #include "utilities/globalDefinitions.hpp" |
aoqi@0 | 30 | /* |
aoqi@0 | 31 | * Per-thread blocking support for JSR166. See the Java-level |
aoqi@0 | 32 | * Documentation for rationale. Basically, park acts like wait, unpark |
aoqi@0 | 33 | * like notify. |
aoqi@0 | 34 | * |
aoqi@0 | 35 | * 6271289 -- |
aoqi@0 | 36 | * To avoid errors where an os thread expires but the JavaThread still |
aoqi@0 | 37 | * exists, Parkers are immortal (type-stable) and are recycled across |
aoqi@0 | 38 | * new threads. This parallels the ParkEvent implementation. |
aoqi@0 | 39 | * Because park-unpark allow spurious wakeups it is harmless if an |
aoqi@0 | 40 | * unpark call unparks a new thread using the old Parker reference. |
aoqi@0 | 41 | * |
aoqi@0 | 42 | * In the future we'll want to think about eliminating Parker and using |
aoqi@0 | 43 | * ParkEvent instead. There's considerable duplication between the two |
aoqi@0 | 44 | * services. |
aoqi@0 | 45 | * |
aoqi@0 | 46 | */ |
aoqi@0 | 47 | |
aoqi@0 | 48 | class Parker : public os::PlatformParker { |
aoqi@0 | 49 | private: |
aoqi@0 | 50 | volatile int _counter ; |
aoqi@0 | 51 | Parker * FreeNext ; |
aoqi@0 | 52 | JavaThread * AssociatedWith ; // Current association |
aoqi@0 | 53 | |
aoqi@0 | 54 | public: |
aoqi@0 | 55 | Parker() : PlatformParker() { |
aoqi@0 | 56 | _counter = 0 ; |
aoqi@0 | 57 | FreeNext = NULL ; |
aoqi@0 | 58 | AssociatedWith = NULL ; |
aoqi@0 | 59 | } |
aoqi@0 | 60 | protected: |
aoqi@0 | 61 | ~Parker() { ShouldNotReachHere(); } |
aoqi@0 | 62 | public: |
aoqi@0 | 63 | // For simplicity of interface with Java, all forms of park (indefinite, |
aoqi@0 | 64 | // relative, and absolute) are multiplexed into one call. |
aoqi@0 | 65 | void park(bool isAbsolute, jlong time); |
aoqi@0 | 66 | void unpark(); |
aoqi@0 | 67 | |
aoqi@0 | 68 | // Lifecycle operators |
aoqi@0 | 69 | static Parker * Allocate (JavaThread * t) ; |
aoqi@0 | 70 | static void Release (Parker * e) ; |
aoqi@0 | 71 | private: |
aoqi@0 | 72 | static Parker * volatile FreeList ; |
aoqi@0 | 73 | static volatile int ListLock ; |
aoqi@0 | 74 | |
aoqi@0 | 75 | }; |
aoqi@0 | 76 | |
aoqi@0 | 77 | ///////////////////////////////////////////////////////////// |
aoqi@0 | 78 | // |
aoqi@0 | 79 | // ParkEvents are type-stable and immortal. |
aoqi@0 | 80 | // |
aoqi@0 | 81 | // Lifecycle: Once a ParkEvent is associated with a thread that ParkEvent remains |
aoqi@0 | 82 | // associated with the thread for the thread's entire lifetime - the relationship is |
aoqi@0 | 83 | // stable. A thread will be associated at most one ParkEvent. When the thread |
aoqi@0 | 84 | // expires, the ParkEvent moves to the EventFreeList. New threads attempt to allocate from |
aoqi@0 | 85 | // the EventFreeList before creating a new Event. Type-stability frees us from |
aoqi@0 | 86 | // worrying about stale Event or Thread references in the objectMonitor subsystem. |
aoqi@0 | 87 | // (A reference to ParkEvent is always valid, even though the event may no longer be associated |
aoqi@0 | 88 | // with the desired or expected thread. A key aspect of this design is that the callers of |
aoqi@0 | 89 | // park, unpark, etc must tolerate stale references and spurious wakeups). |
aoqi@0 | 90 | // |
aoqi@0 | 91 | // Only the "associated" thread can block (park) on the ParkEvent, although |
aoqi@0 | 92 | // any other thread can unpark a reachable parkevent. Park() is allowed to |
aoqi@0 | 93 | // return spuriously. In fact park-unpark a really just an optimization to |
aoqi@0 | 94 | // avoid unbounded spinning and surrender the CPU to be a polite system citizen. |
aoqi@0 | 95 | // A degenerate albeit "impolite" park-unpark implementation could simply return. |
aoqi@0 | 96 | // See http://blogs.sun.com/dave for more details. |
aoqi@0 | 97 | // |
aoqi@0 | 98 | // Eventually I'd like to eliminate Events and ObjectWaiters, both of which serve as |
aoqi@0 | 99 | // thread proxies, and simply make the THREAD structure type-stable and persistent. |
aoqi@0 | 100 | // Currently, we unpark events associated with threads, but ideally we'd just |
aoqi@0 | 101 | // unpark threads. |
aoqi@0 | 102 | // |
aoqi@0 | 103 | // The base-class, PlatformEvent, is platform-specific while the ParkEvent is |
aoqi@0 | 104 | // platform-independent. PlatformEvent provides park(), unpark(), etc., and |
aoqi@0 | 105 | // is abstract -- that is, a PlatformEvent should never be instantiated except |
aoqi@0 | 106 | // as part of a ParkEvent. |
aoqi@0 | 107 | // Equivalently we could have defined a platform-independent base-class that |
aoqi@0 | 108 | // exported Allocate(), Release(), etc. The platform-specific class would extend |
aoqi@0 | 109 | // that base-class, adding park(), unpark(), etc. |
aoqi@0 | 110 | // |
aoqi@0 | 111 | // A word of caution: The JVM uses 2 very similar constructs: |
aoqi@0 | 112 | // 1. ParkEvent are used for Java-level "monitor" synchronization. |
aoqi@0 | 113 | // 2. Parkers are used by JSR166-JUC park-unpark. |
aoqi@0 | 114 | // |
aoqi@0 | 115 | // We'll want to eventually merge these redundant facilities and use ParkEvent. |
aoqi@0 | 116 | |
aoqi@0 | 117 | |
aoqi@0 | 118 | class ParkEvent : public os::PlatformEvent { |
aoqi@0 | 119 | private: |
aoqi@0 | 120 | ParkEvent * FreeNext ; |
aoqi@0 | 121 | |
aoqi@0 | 122 | // Current association |
aoqi@0 | 123 | Thread * AssociatedWith ; |
aoqi@0 | 124 | intptr_t RawThreadIdentity ; // LWPID etc |
aoqi@0 | 125 | volatile int Incarnation ; |
aoqi@0 | 126 | |
aoqi@0 | 127 | // diagnostic : keep track of last thread to wake this thread. |
aoqi@0 | 128 | // this is useful for construction of dependency graphs. |
aoqi@0 | 129 | void * LastWaker ; |
aoqi@0 | 130 | |
aoqi@0 | 131 | public: |
aoqi@0 | 132 | // MCS-CLH list linkage and Native Mutex/Monitor |
aoqi@0 | 133 | ParkEvent * volatile ListNext ; |
aoqi@0 | 134 | ParkEvent * volatile ListPrev ; |
aoqi@0 | 135 | volatile intptr_t OnList ; |
aoqi@0 | 136 | volatile int TState ; |
aoqi@0 | 137 | volatile int Notified ; // for native monitor construct |
aoqi@0 | 138 | volatile int IsWaiting ; // Enqueued on WaitSet |
aoqi@0 | 139 | |
aoqi@0 | 140 | |
aoqi@0 | 141 | private: |
aoqi@0 | 142 | static ParkEvent * volatile FreeList ; |
aoqi@0 | 143 | static volatile int ListLock ; |
aoqi@0 | 144 | |
aoqi@0 | 145 | // It's prudent to mark the dtor as "private" |
aoqi@0 | 146 | // ensuring that it's not visible outside the package. |
aoqi@0 | 147 | // Unfortunately gcc warns about such usage, so |
aoqi@0 | 148 | // we revert to the less desirable "protected" visibility. |
aoqi@0 | 149 | // The other compilers accept private dtors. |
aoqi@0 | 150 | |
aoqi@0 | 151 | protected: // Ensure dtor is never invoked |
aoqi@0 | 152 | ~ParkEvent() { guarantee (0, "invariant") ; } |
aoqi@0 | 153 | |
aoqi@0 | 154 | ParkEvent() : PlatformEvent() { |
aoqi@0 | 155 | AssociatedWith = NULL ; |
aoqi@0 | 156 | FreeNext = NULL ; |
aoqi@0 | 157 | ListNext = NULL ; |
aoqi@0 | 158 | ListPrev = NULL ; |
aoqi@0 | 159 | OnList = 0 ; |
aoqi@0 | 160 | TState = 0 ; |
aoqi@0 | 161 | Notified = 0 ; |
aoqi@0 | 162 | IsWaiting = 0 ; |
aoqi@0 | 163 | } |
aoqi@0 | 164 | |
aoqi@0 | 165 | // We use placement-new to force ParkEvent instances to be |
aoqi@0 | 166 | // aligned on 256-byte address boundaries. This ensures that the least |
aoqi@0 | 167 | // significant byte of a ParkEvent address is always 0. |
aoqi@0 | 168 | |
aoqi@0 | 169 | void * operator new (size_t sz) throw(); |
aoqi@0 | 170 | void operator delete (void * a) ; |
aoqi@0 | 171 | |
aoqi@0 | 172 | public: |
aoqi@0 | 173 | static ParkEvent * Allocate (Thread * t) ; |
aoqi@0 | 174 | static void Release (ParkEvent * e) ; |
aoqi@0 | 175 | } ; |
aoqi@0 | 176 | |
aoqi@0 | 177 | #endif // SHARE_VM_RUNTIME_PARK_HPP |