The Tor Browser: nsprpub/pr/src/threads/combined/prucpu.c@ca08bd8f51b2 (annotated)

nsprpub/pr/src/threads/combined/prucpu.c@ca08bd8f51b2 (annotated)

nsprpub/pr/src/threads/combined/prucpu.c

Wed, 31 Dec 2014 06:55:46 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:55:46 +0100
changeset 1: ca08bd8f51b2
permissions: -rw-r--r--

Added tag TORBROWSER_REPLICA for changeset 6474c204b198

 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #include "primpl.h"
 _PRCPU *_pr_primordialCPU = NULL;
 PRInt32 _pr_md_idle_cpus;       /* number of idle cpus */
 /*
  * The idle threads in MxN models increment/decrement _pr_md_idle_cpus.
  * If _PR_HAVE_ATOMIC_OPS is not defined, they can't use the atomic
  * increment/decrement routines (which are based on PR_Lock/PR_Unlock),
  * because PR_Lock asserts that the calling thread is not an idle thread.
  * So we use a _MDLock to protect _pr_md_idle_cpus.
  */
 #if !defined(_PR_LOCAL_THREADS_ONLY) && !defined(_PR_GLOBAL_THREADS_ONLY)
 #ifndef _PR_HAVE_ATOMIC_OPS
 static _MDLock _pr_md_idle_cpus_lock;
 #endif
 #endif
 PRUintn _pr_numCPU;
 PRInt32 _pr_cpus_exit;
 PRUint32 _pr_cpu_affinity_mask = 0;
 #if !defined (_PR_GLOBAL_THREADS_ONLY)
 static PRUintn _pr_cpuID;
 static void PR_CALLBACK _PR_CPU_Idle(void *);
 static _PRCPU *_PR_CreateCPU(void);
 static PRStatus _PR_StartCPU(_PRCPU *cpu, PRThread *thread);
 #if !defined(_PR_LOCAL_THREADS_ONLY)
 static void _PR_RunCPU(void *arg);
 #endif
 void  _PR_InitCPUs()
 {
     PRThread *me = _PR_MD_CURRENT_THREAD();
     if (_native_threads_only)
         return;
     _pr_cpuID = 0;
     _MD_NEW_LOCK( &_pr_cpuLock);
 #if !defined(_PR_LOCAL_THREADS_ONLY) && !defined(_PR_GLOBAL_THREADS_ONLY)
 #ifndef _PR_HAVE_ATOMIC_OPS
     _MD_NEW_LOCK(&_pr_md_idle_cpus_lock);
 #endif
 #endif
 #ifdef _PR_LOCAL_THREADS_ONLY
 #ifdef HAVE_CUSTOM_USER_THREADS
     _PR_MD_CREATE_PRIMORDIAL_USER_THREAD(me);
 #endif
     /* Now start the first CPU. */
     _pr_primordialCPU = _PR_CreateCPU();
     _pr_numCPU = 1;
     _PR_StartCPU(_pr_primordialCPU, me);
     _PR_MD_SET_CURRENT_CPU(_pr_primordialCPU);
     /* Initialize cpu for current thread (could be different from me) */
     _PR_MD_CURRENT_THREAD()->cpu = _pr_primordialCPU;
     _PR_MD_SET_LAST_THREAD(me);
 #else /* Combined MxN model */
     _pr_primordialCPU = _PR_CreateCPU();
     _pr_numCPU = 1;
     _PR_CreateThread(PR_SYSTEM_THREAD,
                      _PR_RunCPU,
                      _pr_primordialCPU,
                      PR_PRIORITY_NORMAL,
                      PR_GLOBAL_THREAD,
                      PR_UNJOINABLE_THREAD,
 ,
                      _PR_IDLE_THREAD);
 #endif /* _PR_LOCAL_THREADS_ONLY */
     _PR_MD_INIT_CPUS();
 }
 #ifdef WINNT
 /*
  * Right now this function merely stops the CPUs and does
  * not do any other cleanup.
  *
  * It is only implemented for WINNT because bug 161998 only
  * affects the WINNT version of NSPR, but it would be nice
  * to implement this function for other platforms too.
  */
 void _PR_CleanupCPUs(void)
 {
     PRUintn i;
     PRCList *qp;
     _PRCPU *cpu;
     _pr_cpus_exit = 1;
     for (i = 0; i < _pr_numCPU; i++) {
         _PR_MD_WAKEUP_WAITER(NULL);
     }
     for (qp = _PR_CPUQ().next; qp != &_PR_CPUQ(); qp = qp->next) {
         cpu = _PR_CPU_PTR(qp);
         _PR_MD_JOIN_THREAD(&cpu->thread->md);
     }
 }
 #endif
 static _PRCPUQueue *_PR_CreateCPUQueue(void)
 {
     PRInt32 index;
     _PRCPUQueue *cpuQueue;
     cpuQueue = PR_NEWZAP(_PRCPUQueue);
     _MD_NEW_LOCK( &cpuQueue->runQLock );
     _MD_NEW_LOCK( &cpuQueue->sleepQLock );
     _MD_NEW_LOCK( &cpuQueue->miscQLock );
     for (index = 0; index < PR_PRIORITY_LAST + 1; index++)
         PR_INIT_CLIST( &(cpuQueue->runQ[index]) );
     PR_INIT_CLIST( &(cpuQueue->sleepQ) );
     PR_INIT_CLIST( &(cpuQueue->pauseQ) );
     PR_INIT_CLIST( &(cpuQueue->suspendQ) );
     PR_INIT_CLIST( &(cpuQueue->waitingToJoinQ) );
     cpuQueue->numCPUs = 1;
     return cpuQueue;
 }
 /*
  * Create a new CPU.
  *
  * This function initializes enough of the _PRCPU structure so
  * that it can be accessed safely by a global thread or another
  * CPU.  This function does not create the native thread that
  * will run the CPU nor does it initialize the parts of _PRCPU
  * that must be initialized by that native thread.
  *
  * The reason we cannot simply have the native thread create
  * and fully initialize a new CPU is that we need to be able to
  * create a usable _pr_primordialCPU in _PR_InitCPUs without
  * assuming that the primordial CPU thread we created can run
  * during NSPR initialization.  For example, on Windows while
  * new threads can be created by DllMain, they won't be able
  * to run during DLL initialization.  If NSPR is initialized
  * by DllMain, the primordial CPU thread won't run until DLL
  * initialization is finished.
  */
 static _PRCPU *_PR_CreateCPU(void)
 {
     _PRCPU *cpu;
     cpu = PR_NEWZAP(_PRCPU);
     if (cpu) {
         cpu->queue = _PR_CreateCPUQueue();
         if (!cpu->queue) {
             PR_DELETE(cpu);
             return NULL;
         }
     }
     return cpu;
 }
 /*
  * Start a new CPU.
  *
  * 'cpu' is a _PRCPU structure created by _PR_CreateCPU().
  * 'thread' is the native thread that will run the CPU.
  *
  * If this function fails, 'cpu' is destroyed.
  */
 static PRStatus _PR_StartCPU(_PRCPU *cpu, PRThread *thread)
 {
     /*
     ** Start a new cpu. The assumption this code makes is that the
     ** underlying operating system creates a stack to go with the new
     ** native thread. That stack will be used by the cpu when pausing.
     */
     PR_ASSERT(!_native_threads_only);
     cpu->last_clock = PR_IntervalNow();
     /* Before we create any threads on this CPU we have to
      * set the current CPU
      */
     _PR_MD_SET_CURRENT_CPU(cpu);
     _PR_MD_INIT_RUNNING_CPU(cpu);
     thread->cpu = cpu;
     cpu->idle_thread = _PR_CreateThread(PR_SYSTEM_THREAD,
                                         _PR_CPU_Idle,
                                         (void *)cpu,
                                         PR_PRIORITY_NORMAL,
                                         PR_LOCAL_THREAD,
                                         PR_UNJOINABLE_THREAD,
 ,
                                         _PR_IDLE_THREAD);
     if (!cpu->idle_thread) {
         /* didn't clean up CPU queue XXXMB */
         PR_DELETE(cpu);
         return PR_FAILURE;
     }
     PR_ASSERT(cpu->idle_thread->cpu == cpu);
     cpu->idle_thread->no_sched = 0;
     cpu->thread = thread;
     if (_pr_cpu_affinity_mask)
         PR_SetThreadAffinityMask(thread, _pr_cpu_affinity_mask);
     /* Created and started a new CPU */
     _PR_CPU_LIST_LOCK();
     cpu->id = _pr_cpuID++;
     PR_APPEND_LINK(&cpu->links, &_PR_CPUQ());
     _PR_CPU_LIST_UNLOCK();
     return PR_SUCCESS;
 }
 #if !defined(_PR_GLOBAL_THREADS_ONLY) && !defined(_PR_LOCAL_THREADS_ONLY)
 /*
 ** This code is used during a cpu's initial creation.
 */
 static void _PR_RunCPU(void *arg)
 {
     _PRCPU *cpu = (_PRCPU *)arg;
     PRThread *me = _PR_MD_CURRENT_THREAD();
     PR_ASSERT(NULL != me);
     /*
      * _PR_StartCPU calls _PR_CreateThread to create the
      * idle thread.  Because _PR_CreateThread calls PR_Lock,
      * the current thread has to remain a global thread
      * during the _PR_StartCPU call so that it can wait for
      * the lock if the lock is held by another thread.  If
      * we clear the _PR_GLOBAL_SCOPE flag in
      * _PR_MD_CREATE_PRIMORDIAL_THREAD, the current thread
      * will be treated as a local thread and have trouble
      * waiting for the lock because the CPU is not fully
      * constructed yet.
      *
      * After the CPU is started, it is safe to mark the
      * current thread as a local thread.
      */
 #ifdef HAVE_CUSTOM_USER_THREADS
     _PR_MD_CREATE_PRIMORDIAL_USER_THREAD(me);
 #endif
     me->no_sched = 1;
     _PR_StartCPU(cpu, me);
 #ifdef HAVE_CUSTOM_USER_THREADS
     me->flags &= (~_PR_GLOBAL_SCOPE);
 #endif
     _PR_MD_SET_CURRENT_CPU(cpu);
     _PR_MD_SET_CURRENT_THREAD(cpu->thread);
     me->cpu = cpu;
     while(1) {
         PRInt32 is;
         if (!_PR_IS_NATIVE_THREAD(me)) _PR_INTSOFF(is);
 	    _PR_MD_START_INTERRUPTS();
         _PR_MD_SWITCH_CONTEXT(me);
     }
 }
 #endif
 static void PR_CALLBACK _PR_CPU_Idle(void *_cpu)
 {
     _PRCPU *cpu = (_PRCPU *)_cpu;
     PRThread *me = _PR_MD_CURRENT_THREAD();
     PR_ASSERT(NULL != me);
     me->cpu = cpu;
     cpu->idle_thread = me;
     if (_MD_LAST_THREAD())
         _MD_LAST_THREAD()->no_sched = 0;
     if (!_PR_IS_NATIVE_THREAD(me)) _PR_MD_SET_INTSOFF(0);
     while(1) {
         PRInt32 is;
         PRIntervalTime timeout;
         if (!_PR_IS_NATIVE_THREAD(me)) _PR_INTSOFF(is);
         _PR_RUNQ_LOCK(cpu);
 #if !defined(_PR_LOCAL_THREADS_ONLY) && !defined(_PR_GLOBAL_THREADS_ONLY)
 #ifdef _PR_HAVE_ATOMIC_OPS
         _PR_MD_ATOMIC_INCREMENT(&_pr_md_idle_cpus);
 #else
         _PR_MD_LOCK(&_pr_md_idle_cpus_lock);
         _pr_md_idle_cpus++;
         _PR_MD_UNLOCK(&_pr_md_idle_cpus_lock);
 #endif /* _PR_HAVE_ATOMIC_OPS */
 #endif
         /* If someone on runq; do a nonblocking PAUSECPU */
         if (_PR_RUNQREADYMASK(me->cpu) != 0) {
             _PR_RUNQ_UNLOCK(cpu);
             timeout = PR_INTERVAL_NO_WAIT;
         } else {
             _PR_RUNQ_UNLOCK(cpu);
             _PR_SLEEPQ_LOCK(cpu);
             if (PR_CLIST_IS_EMPTY(&_PR_SLEEPQ(me->cpu))) {
                 timeout = PR_INTERVAL_NO_TIMEOUT;
             } else {
                 PRThread *wakeThread;
                 wakeThread = _PR_THREAD_PTR(_PR_SLEEPQ(me->cpu).next);
                 timeout = wakeThread->sleep;
             }
             _PR_SLEEPQ_UNLOCK(cpu);
         }
         /* Wait for an IO to complete */
         (void)_PR_MD_PAUSE_CPU(timeout);
 #ifdef WINNT
         if (_pr_cpus_exit) {
             /* _PR_CleanupCPUs tells us to exit */
             _PR_MD_END_THREAD();
         }
 #endif
 #if !defined(_PR_LOCAL_THREADS_ONLY) && !defined(_PR_GLOBAL_THREADS_ONLY)
 #ifdef _PR_HAVE_ATOMIC_OPS
         _PR_MD_ATOMIC_DECREMENT(&_pr_md_idle_cpus);
 #else
         _PR_MD_LOCK(&_pr_md_idle_cpus_lock);
         _pr_md_idle_cpus--;
         _PR_MD_UNLOCK(&_pr_md_idle_cpus_lock);
 #endif /* _PR_HAVE_ATOMIC_OPS */
 #endif
 		_PR_ClockInterrupt();
 		/* Now schedule any thread that is on the runq
 		 * INTS must be OFF when calling PR_Schedule()
 		 */
 		me->state = _PR_RUNNABLE;
 		_PR_MD_SWITCH_CONTEXT(me);
 		if (!_PR_IS_NATIVE_THREAD(me)) _PR_FAST_INTSON(is);
     }
 }
 #endif /* _PR_GLOBAL_THREADS_ONLY */
 PR_IMPLEMENT(void) PR_SetConcurrency(PRUintn numCPUs)
 {
 #if defined(_PR_GLOBAL_THREADS_ONLY) || defined(_PR_LOCAL_THREADS_ONLY)
     /* do nothing */
 #else /* combined, MxN thread model */
     PRUintn newCPU;
     _PRCPU *cpu;
     PRThread *thr;
     if (!_pr_initialized) _PR_ImplicitInitialization();
 	if (_native_threads_only)
 		return;
     _PR_CPU_LIST_LOCK();
     if (_pr_numCPU < numCPUs) {
         newCPU = numCPUs - _pr_numCPU;
         _pr_numCPU = numCPUs;
     } else newCPU = 0;
     _PR_CPU_LIST_UNLOCK();
     for (; newCPU; newCPU--) {
         cpu = _PR_CreateCPU();
         thr = _PR_CreateThread(PR_SYSTEM_THREAD,
                               _PR_RunCPU,
                               cpu,
                               PR_PRIORITY_NORMAL,
                               PR_GLOBAL_THREAD,
                               PR_UNJOINABLE_THREAD,
 ,
                               _PR_IDLE_THREAD);
     }
 #endif
 }
 PR_IMPLEMENT(_PRCPU *) _PR_GetPrimordialCPU(void)
 {
     if (_pr_primordialCPU)
         return _pr_primordialCPU;
     else
         return _PR_MD_CURRENT_CPU();
 }

The Tor Browser / annotate

nsprpub/pr/src/threads/combined/prucpu.c@ca08bd8f51b2 (annotated)

nsprpub/pr/src/threads/combined/prucpu.c