Mercurial > hg > graal-jvmci-8
comparison src/share/vm/runtime/thread.hpp @ 1878:fa83ab460c54
6988353: refactor contended sync subsystem
Summary: reduce complexity by factoring synchronizer.cpp
Reviewed-by: dholmes, never, coleenp
author | acorn |
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date | Fri, 22 Oct 2010 15:59:34 -0400 |
parents | 0715f0cf171d |
children | 2d26b0046e0d f95d63e2154a |
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1874:75ab0162aa84 | 1878:fa83ab460c54 |
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28 class JvmtiThreadState; | 28 class JvmtiThreadState; |
29 class JvmtiGetLoadedClassesClosure; | 29 class JvmtiGetLoadedClassesClosure; |
30 class ThreadStatistics; | 30 class ThreadStatistics; |
31 class ConcurrentLocksDump; | 31 class ConcurrentLocksDump; |
32 class ParkEvent ; | 32 class ParkEvent ; |
33 class Parker; | |
33 | 34 |
34 class ciEnv; | 35 class ciEnv; |
35 class CompileThread; | 36 class CompileThread; |
36 class CompileLog; | 37 class CompileLog; |
37 class CompileTask; | 38 class CompileTask; |
542 static void SpinAcquire (volatile int * Lock, const char * Name) ; | 543 static void SpinAcquire (volatile int * Lock, const char * Name) ; |
543 static void SpinRelease (volatile int * Lock) ; | 544 static void SpinRelease (volatile int * Lock) ; |
544 static void muxAcquire (volatile intptr_t * Lock, const char * Name) ; | 545 static void muxAcquire (volatile intptr_t * Lock, const char * Name) ; |
545 static void muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) ; | 546 static void muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) ; |
546 static void muxRelease (volatile intptr_t * Lock) ; | 547 static void muxRelease (volatile intptr_t * Lock) ; |
547 | |
548 }; | 548 }; |
549 | 549 |
550 // Inline implementation of Thread::current() | 550 // Inline implementation of Thread::current() |
551 // Thread::current is "hot" it's called > 128K times in the 1st 500 msecs of | 551 // Thread::current is "hot" it's called > 128K times in the 1st 500 msecs of |
552 // startup. | 552 // startup. |
1767 if (_thread) _thread->leave_signal_handler(); | 1767 if (_thread) _thread->leave_signal_handler(); |
1768 _thread = NULL; | 1768 _thread = NULL; |
1769 } | 1769 } |
1770 }; | 1770 }; |
1771 | 1771 |
1772 // ParkEvents are type-stable and immortal. | |
1773 // | |
1774 // Lifecycle: Once a ParkEvent is associated with a thread that ParkEvent remains | |
1775 // associated with the thread for the thread's entire lifetime - the relationship is | |
1776 // stable. A thread will be associated at most one ParkEvent. When the thread | |
1777 // expires, the ParkEvent moves to the EventFreeList. New threads attempt to allocate from | |
1778 // the EventFreeList before creating a new Event. Type-stability frees us from | |
1779 // worrying about stale Event or Thread references in the objectMonitor subsystem. | |
1780 // (A reference to ParkEvent is always valid, even though the event may no longer be associated | |
1781 // with the desired or expected thread. A key aspect of this design is that the callers of | |
1782 // park, unpark, etc must tolerate stale references and spurious wakeups). | |
1783 // | |
1784 // Only the "associated" thread can block (park) on the ParkEvent, although | |
1785 // any other thread can unpark a reachable parkevent. Park() is allowed to | |
1786 // return spuriously. In fact park-unpark a really just an optimization to | |
1787 // avoid unbounded spinning and surrender the CPU to be a polite system citizen. | |
1788 // A degenerate albeit "impolite" park-unpark implementation could simply return. | |
1789 // See http://blogs.sun.com/dave for more details. | |
1790 // | |
1791 // Eventually I'd like to eliminate Events and ObjectWaiters, both of which serve as | |
1792 // thread proxies, and simply make the THREAD structure type-stable and persistent. | |
1793 // Currently, we unpark events associated with threads, but ideally we'd just | |
1794 // unpark threads. | |
1795 // | |
1796 // The base-class, PlatformEvent, is platform-specific while the ParkEvent is | |
1797 // platform-independent. PlatformEvent provides park(), unpark(), etc., and | |
1798 // is abstract -- that is, a PlatformEvent should never be instantiated except | |
1799 // as part of a ParkEvent. | |
1800 // Equivalently we could have defined a platform-independent base-class that | |
1801 // exported Allocate(), Release(), etc. The platform-specific class would extend | |
1802 // that base-class, adding park(), unpark(), etc. | |
1803 // | |
1804 // A word of caution: The JVM uses 2 very similar constructs: | |
1805 // 1. ParkEvent are used for Java-level "monitor" synchronization. | |
1806 // 2. Parkers are used by JSR166-JUC park-unpark. | |
1807 // | |
1808 // We'll want to eventually merge these redundant facilities and use ParkEvent. | |
1809 | |
1810 | |
1811 class ParkEvent : public os::PlatformEvent { | |
1812 private: | |
1813 ParkEvent * FreeNext ; | |
1814 | |
1815 // Current association | |
1816 Thread * AssociatedWith ; | |
1817 intptr_t RawThreadIdentity ; // LWPID etc | |
1818 volatile int Incarnation ; | |
1819 | |
1820 // diagnostic : keep track of last thread to wake this thread. | |
1821 // this is useful for construction of dependency graphs. | |
1822 void * LastWaker ; | |
1823 | |
1824 public: | |
1825 // MCS-CLH list linkage and Native Mutex/Monitor | |
1826 ParkEvent * volatile ListNext ; | |
1827 ParkEvent * volatile ListPrev ; | |
1828 volatile intptr_t OnList ; | |
1829 volatile int TState ; | |
1830 volatile int Notified ; // for native monitor construct | |
1831 volatile int IsWaiting ; // Enqueued on WaitSet | |
1832 | |
1833 | |
1834 private: | |
1835 static ParkEvent * volatile FreeList ; | |
1836 static volatile int ListLock ; | |
1837 | |
1838 // It's prudent to mark the dtor as "private" | |
1839 // ensuring that it's not visible outside the package. | |
1840 // Unfortunately gcc warns about such usage, so | |
1841 // we revert to the less desirable "protected" visibility. | |
1842 // The other compilers accept private dtors. | |
1843 | |
1844 protected: // Ensure dtor is never invoked | |
1845 ~ParkEvent() { guarantee (0, "invariant") ; } | |
1846 | |
1847 ParkEvent() : PlatformEvent() { | |
1848 AssociatedWith = NULL ; | |
1849 FreeNext = NULL ; | |
1850 ListNext = NULL ; | |
1851 ListPrev = NULL ; | |
1852 OnList = 0 ; | |
1853 TState = 0 ; | |
1854 Notified = 0 ; | |
1855 IsWaiting = 0 ; | |
1856 } | |
1857 | |
1858 // We use placement-new to force ParkEvent instances to be | |
1859 // aligned on 256-byte address boundaries. This ensures that the least | |
1860 // significant byte of a ParkEvent address is always 0. | |
1861 | |
1862 void * operator new (size_t sz) ; | |
1863 void operator delete (void * a) ; | |
1864 | |
1865 public: | |
1866 static ParkEvent * Allocate (Thread * t) ; | |
1867 static void Release (ParkEvent * e) ; | |
1868 } ; |