diff options
Diffstat (limited to 'libjava/include/posix-threads.h')
| -rw-r--r-- | libjava/include/posix-threads.h | 163 |
1 files changed, 159 insertions, 4 deletions
diff --git a/libjava/include/posix-threads.h b/libjava/include/posix-threads.h index ad09bedd45a..e033209d088 100644 --- a/libjava/include/posix-threads.h +++ b/libjava/include/posix-threads.h @@ -1,7 +1,7 @@ // -*- c++ -*- // posix-threads.h - Defines for using POSIX threads. -/* Copyright (C) 1998, 1999 Free Software Foundation +/* Copyright (C) 1998, 1999, 2001 Free Software Foundation This file is part of libgcj. @@ -106,10 +106,21 @@ _Jv_CondInit (_Jv_ConditionVariable_t *cv) // Mutexes. // +#ifdef LOCK_DEBUG +# include <stdio.h> +#endif + inline void _Jv_MutexInit (_Jv_Mutex_t *mu) { +# ifdef LOCK_DEBUG /* Assumes Linuxthreads */ + pthread_mutexattr_t attr; + pthread_mutexattr_init(&attr); + pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_ERRORCHECK); + pthread_mutex_init (&mu->mutex, &attr); +# else pthread_mutex_init (&mu->mutex, 0); +# endif mu->count = 0; mu->owner = 0; @@ -125,7 +136,16 @@ _Jv_MutexLock (_Jv_Mutex_t *mu) } else { - pthread_mutex_lock (&mu->mutex); +# ifdef LOCK_DEBUG + int result = pthread_mutex_lock (&mu->mutex); + if (0 != result) + { + fprintf(stderr, "Pthread_mutex_lock returned %d\n", result); + for (;;) {} + } +# else + pthread_mutex_lock (&mu->mutex); +# endif mu->count = 1; mu->owner = self; } @@ -136,14 +156,29 @@ inline int _Jv_MutexUnlock (_Jv_Mutex_t *mu) { if (_Jv_PthreadCheckMonitor (mu)) - return 1; + { +# ifdef LOCK_DEBUG + fprintf(stderr, "_Jv_MutexUnlock: Not owner\n"); + for (;;) {} +# endif + return 1; + } mu->count--; if (mu->count == 0) { mu->owner = 0; - pthread_mutex_unlock (&mu->mutex); +# ifdef LOCK_DEBUG + int result = pthread_mutex_unlock (&mu->mutex); + if (0 != result) + { + fprintf(stderr, "Pthread_mutex_unlock returned %d\n", result); + for (;;) {} + } +# else + pthread_mutex_unlock (&mu->mutex); +# endif } return 0; } @@ -179,6 +214,126 @@ _Jv_ThreadCurrent (void) return (java::lang::Thread *) pthread_getspecific (_Jv_ThreadKey); } +#ifdef JV_HASH_SYNCHRONIZATION +// Should be specialized to just load the "current thread" register +// on platforms that support it. Speed is of the essence. The value +// of the descriptor is not, so long as there is a one-to-one correspondence +// to threads. + + +#ifdef __i386__ + +#define SLOW_PTHREAD_SELF + // Add a cache for pthread_self() if we don't have the thread + // pointer in a register. + +#endif /* __i386__ */ + +#ifdef __ia64__ + +typedef size_t _Jv_ThreadId_t; + +register size_t _Jv_self __asm__("r13"); + // For linux_threads this is really a pointer to its thread data + // structure. We treat it as opaque. That should also work + // on other operating systems that follow the ABI standard. + +// This should become the prototype for machines that maintain a thread +// pointer in a register. +inline _Jv_ThreadId_t +_Jv_ThreadSelf (void) +{ + return _Jv_self; +} + +#define JV_SELF_DEFINED + +#endif /* __ia64__ */ + +#if defined(SLOW_PTHREAD_SELF) + +typedef pthread_t _Jv_ThreadId_t; + +// E.g. on X86 Linux, pthread_self() is too slow for our purpose. +// Instead we maintain a cache based on the current sp value. +// This is similar to what's done for thread local allocation in the +// GC, only far simpler. +// This code should probably go away when Linux/X86 starts using a +// segment register to hold the thread id. +# define LOG_THREAD_SPACING 12 + // If two thread pointer values are closer than + // 1 << LOG_THREAD_SPACING, we assume they belong + // to the same thread. +# define SELF_CACHE_SIZE 1024 +# define SC_INDEX(sp) (((unsigned long)(sp) >> 19) & (SELF_CACHE_SIZE-1)) + // Mapping from sp value to cache index. + // Note that this is not in any real sense a hash + // function, since we need to be able to clear + // all possibly matching slots on thread startup. + // Thus all entries that might correspond to + // a given thread are intentionally contiguous. + // Works well with anything that allocates at least + // 512KB stacks. +# define SC_CLEAR_MIN (-16) // When starting a new thread, we clear +# define SC_CLEAR_MAX 0 // all self cache entries between + // SC_INDEX(sp)+SC_CLEAR_MIN and + // SC_INDEX(sp)+SC_CLEAR_MAX to ensure + // we never see stale values. The + // current values assume a downward + // growing stack of size <= 7.5 MB. +# define BAD_HIGH_SP_VALUE ((size_t)(-1)) + +extern volatile +struct self_cache_entry { + size_t high_sp_bits; // sp value >> LOG_THREAD_SPACING + pthread_t self; // Corresponding thread +} _Jv_self_cache[]; + +void _Jv_Self_Cache_Init(); + +_Jv_ThreadId_t +_Jv_ThreadSelf_out_of_line(volatile self_cache_entry *sce, + size_t high_sp_bits); + +inline _Jv_ThreadId_t +_Jv_ThreadSelf (void) +{ + int dummy; + size_t sp = (size_t)(&dummy); + unsigned h = SC_INDEX(sp); + volatile self_cache_entry *sce = _Jv_self_cache + h; + pthread_t candidate_self = sce -> self; // Read must precede following one. + // Read barrier goes here, if needed. + if (sce -> high_sp_bits == sp >> LOG_THREAD_SPACING) + { + // The sce -> self value we read must be valid. An intervening + // cache replacement by another thread would have first replaced + // high_sp_bits by something else, and it can't possibly change + // back without our intervention. + return candidate_self; + } + else + return _Jv_ThreadSelf_out_of_line(sce, sp >> LOG_THREAD_SPACING); +} + +#define JV_SELF_DEFINED + +#endif /* SLOW_PTHREAD_SELF */ + +#ifndef JV_SELF_DEFINED /* If all else fails, call pthread_self directly */ + +typedef pthread_t _Jv_ThreadId_t; + +inline _Jv_ThreadId_t +_Jv_ThreadSelf (void) +{ + return pthread_self(); +} + +#endif /* !JV_SELF_DEFINED */ + +#endif /* JV_HASH_SYNCHRONIZATION */ + inline _Jv_Thread_t * _Jv_ThreadCurrentData (void) { |