Source code
Revision control
Copy as Markdown
Other Tools
/* -*- 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
#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,
0, _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.
*
* 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_ARRAY_SIZE(cpuQueue->runQ); 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, 0, _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, 0, _PR_IDLE_THREAD);
}
#endif
}
PR_IMPLEMENT(_PRCPU*) _PR_GetPrimordialCPU(void) {
if (_pr_primordialCPU) {
return _pr_primordialCPU;
} else {
return _PR_MD_CURRENT_CPU();
}
}