/* * Mach Operating System * Copyright (c) 1994-1987 Carnegie Mellon University * All Rights Reserved. * * Permission to use, copy, modify and distribute this software and its * documentation is hereby granted, provided that both the copyright * notice and this permission notice appear in all copies of the * software, derivative works or modified versions, and any portions * thereof, and that both notices appear in supporting documentation. * * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. * * Carnegie Mellon requests users of this software to return to * * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU * School of Computer Science * Carnegie Mellon University * Pittsburgh PA 15213-3890 * * any improvements or extensions that they make and grant Carnegie Mellon * the rights to redistribute these changes. */ /* * File: kern/thread.c * Author: Avadis Tevanian, Jr., Michael Wayne Young, David Golub * Date: 1986 * * Thread management primitives implementation. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* for splsched */ #include #include /* for MACHINE_STACK */ thread_t active_threads[NCPUS]; vm_offset_t active_stacks[NCPUS]; struct kmem_cache thread_cache; queue_head_t reaper_queue; decl_simple_lock_data(, reaper_lock) /* private */ struct thread thread_template; #if MACH_DEBUG #define STACK_MARKER 0xdeadbeefU boolean_t stack_check_usage = FALSE; decl_simple_lock_data(, stack_usage_lock) vm_size_t stack_max_usage = 0; #endif /* MACH_DEBUG */ /* * Machine-dependent code must define: * pcb_init * pcb_terminate * pcb_collect * * The thread->pcb field is reserved for machine-dependent code. */ #ifdef MACHINE_STACK /* * Machine-dependent code must define: * stack_alloc_try * stack_alloc * stack_free * stack_handoff * stack_collect */ #else /* MACHINE_STACK */ /* * We allocate stacks from generic kernel VM. * Machine-dependent code must define: * stack_attach * stack_detach * stack_handoff * * The stack_free_list can only be accessed at splsched, * because stack_alloc_try/thread_invoke operate at splsched. */ decl_simple_lock_data(, stack_lock_data)/* splsched only */ #define stack_lock() simple_lock(&stack_lock_data) #define stack_unlock() simple_unlock(&stack_lock_data) /* * We allocate kernel stacks using the slab allocator. */ static struct kmem_cache stack_cache; /* * stack_alloc_try: * * Non-blocking attempt to allocate a kernel stack. * Called at splsched with the thread locked. */ boolean_t stack_alloc_try( thread_t thread, void (*resume)(thread_t)) { vm_offset_t stack; stack = kmem_cache_alloc(&stack_cache); assert ((stack & (KERNEL_STACK_SIZE-1)) == 0); #if MACH_DEBUG if (stack) stack_init(stack); #endif /* MACH_DEBUG */ if (! stack) stack = thread->stack_privilege; if (stack != 0) { stack_attach(thread, stack, resume); return TRUE; } else { return FALSE; } } /* * stack_alloc: * * Allocate a kernel stack for a thread. */ kern_return_t stack_alloc( thread_t thread, void (*resume)(thread_t)) { if (! stack_alloc_try (thread, resume)) return KERN_RESOURCE_SHORTAGE; return KERN_SUCCESS; } /* * stack_free: * * Free a thread's kernel stack. * Called at splsched with the thread locked. */ void stack_free( thread_t thread) { vm_offset_t stack; stack = stack_detach(thread); if (stack != thread->stack_privilege) kmem_cache_free (&stack_cache, stack); } /* * stack_collect: * * Free excess kernel stacks. * May block. */ void stack_collect(void) { } #endif /* MACHINE_STACK */ /* * stack_privilege: * * stack_alloc_try on this thread must always succeed. */ void stack_privilege( thread_t thread) { /* * This implementation only works for the current thread. */ if (thread != current_thread()) panic("stack_privilege"); if (thread->stack_privilege == 0) thread->stack_privilege = current_stack(); } void thread_init(void) { kmem_cache_init(&thread_cache, "thread", sizeof(struct thread), 0, NULL, NULL, NULL, 0); /* * Kernel stacks should be naturally aligned, so that it * is easy to find the starting/ending addresses of a * stack given an address in the middle. */ kmem_cache_init(&stack_cache, "stack", KERNEL_STACK_SIZE, KERNEL_STACK_SIZE, NULL, NULL, NULL, 0); /* * Fill in a template thread for fast initialization. * [Fields that must be (or are typically) reset at * time of creation are so noted.] */ /* thread_template.links (none) */ thread_template.runq = RUN_QUEUE_NULL; /* thread_template.task (later) */ /* thread_template.thread_list (later) */ /* thread_template.pset_threads (later) */ /* thread_template.lock (later) */ /* one ref for being alive; one for the guy who creates the thread */ thread_template.ref_count = 2; thread_template.pcb = (pcb_t) 0; /* (reset) */ thread_template.kernel_stack = (vm_offset_t) 0; thread_template.stack_privilege = (vm_offset_t) 0; thread_template.wait_event = 0; /* thread_template.suspend_count (later) */ thread_template.wait_result = KERN_SUCCESS; thread_template.wake_active = FALSE; thread_template.state = TH_SUSP | TH_SWAPPED; thread_template.swap_func = thread_bootstrap_return; /* thread_template.priority (later) */ thread_template.max_priority = BASEPRI_USER; /* thread_template.sched_pri (later - compute_priority) */ #if MACH_FIXPRI thread_template.sched_data = 0; thread_template.policy = POLICY_TIMESHARE; #endif /* MACH_FIXPRI */ thread_template.depress_priority = -1; thread_template.cpu_usage = 0; thread_template.sched_usage = 0; /* thread_template.sched_stamp (later) */ thread_template.recover = (vm_offset_t) 0; thread_template.vm_privilege = FALSE; thread_template.user_stop_count = 1; /* thread_template. (later) */ timer_init(&(thread_template.user_timer)); timer_init(&(thread_template.system_timer)); thread_template.user_timer_save.low = 0; thread_template.user_timer_save.high = 0; thread_template.system_timer_save.low = 0; thread_template.system_timer_save.high = 0; thread_template.cpu_delta = 0; thread_template.sched_delta = 0; thread_template.active = FALSE; /* reset */ thread_template.ast = AST_ZILCH; /* thread_template.processor_set (later) */ thread_template.bound_processor = PROCESSOR_NULL; #if MACH_HOST thread_template.may_assign = TRUE; thread_template.assign_active = FALSE; #endif /* MACH_HOST */ #if NCPUS > 1 /* thread_template.last_processor (later) */ #endif /* NCPUS > 1 */ /* * Initialize other data structures used in * this module. */ queue_init(&reaper_queue); simple_lock_init(&reaper_lock); #ifndef MACHINE_STACK simple_lock_init(&stack_lock_data); #endif /* MACHINE_STACK */ #if MACH_DEBUG simple_lock_init(&stack_usage_lock); #endif /* MACH_DEBUG */ /* * Initialize any machine-dependent * per-thread structures necessary. */ pcb_module_init(); } kern_return_t thread_create( task_t parent_task, thread_t *child_thread) /* OUT */ { thread_t new_thread; processor_set_t pset; if (parent_task == TASK_NULL) return KERN_INVALID_ARGUMENT; /* * Allocate a thread and initialize static fields */ new_thread = (thread_t) kmem_cache_alloc(&thread_cache); if (new_thread == THREAD_NULL) return KERN_RESOURCE_SHORTAGE; *new_thread = thread_template; record_time_stamp (&new_thread->creation_time); /* * Initialize runtime-dependent fields */ new_thread->task = parent_task; simple_lock_init(&new_thread->lock); new_thread->sched_stamp = sched_tick; thread_timeout_setup(new_thread); /* * Create a pcb. The kernel stack is created later, * when the thread is swapped-in. */ pcb_init(new_thread); ipc_thread_init(new_thread); /* * Find the processor set for the parent task. */ task_lock(parent_task); pset = parent_task->processor_set; pset_reference(pset); task_unlock(parent_task); /* * Lock both the processor set and the task, * so that the thread can be added to both * simultaneously. Processor set must be * locked first. */ Restart: pset_lock(pset); task_lock(parent_task); /* * If the task has changed processor sets, * catch up (involves lots of lock juggling). */ { processor_set_t cur_pset; cur_pset = parent_task->processor_set; if (!cur_pset->active) cur_pset = &default_pset; if (cur_pset != pset) { pset_reference(cur_pset); task_unlock(parent_task); pset_unlock(pset); pset_deallocate(pset); pset = cur_pset; goto Restart; } } /* * Set the thread`s priority from the pset and task. */ new_thread->priority = parent_task->priority; if (pset->max_priority > new_thread->max_priority) new_thread->max_priority = pset->max_priority; if (new_thread->max_priority > new_thread->priority) new_thread->priority = new_thread->max_priority; /* * Don't need to lock thread here because it can't * possibly execute and no one else knows about it. */ compute_priority(new_thread, TRUE); /* * Thread is suspended if the task is. Add 1 to * suspend count since thread is created in suspended * state. */ new_thread->suspend_count = parent_task->suspend_count + 1; /* * Add the thread to the processor set. * If the pset is empty, suspend the thread again. */ pset_add_thread(pset, new_thread); if (pset->empty) new_thread->suspend_count++; #if HW_FOOTPRINT /* * Need to set last_processor, idle processor would be best, but * that requires extra locking nonsense. Go for tail of * processors queue to avoid master. */ if (!pset->empty) { new_thread->last_processor = (processor_t)queue_first(&pset->processors); } else { /* * Thread created in empty processor set. Pick * master processor as an acceptable legal value. */ new_thread->last_processor = master_processor; } #else /* HW_FOOTPRINT */ /* * Don't need to initialize because the context switch * code will set it before it can be used. */ #endif /* HW_FOOTPRINT */ #if MACH_PCSAMPLE new_thread->pc_sample.seqno = 0; new_thread->pc_sample.sampletypes = 0; #endif /* MACH_PCSAMPLE */ new_thread->pc_sample.buffer = 0; /* * Add the thread to the task`s list of threads. * The new thread holds another reference to the task. */ parent_task->ref_count++; parent_task->thread_count++; queue_enter(&parent_task->thread_list, new_thread, thread_t, thread_list); /* * Finally, mark the thread active. */ new_thread->active = TRUE; if (!parent_task->active) { task_unlock(parent_task); pset_unlock(pset); (void) thread_terminate(new_thread); /* release ref we would have given our caller */ thread_deallocate(new_thread); return KERN_FAILURE; } task_unlock(parent_task); pset_unlock(pset); ipc_thread_enable(new_thread); *child_thread = new_thread; return KERN_SUCCESS; } unsigned int thread_deallocate_stack = 0; void thread_deallocate( thread_t thread) { spl_t s; task_t task; processor_set_t pset; time_value_t user_time, system_time; if (thread == THREAD_NULL) return; /* * First, check for new count > 0 (the common case). * Only the thread needs to be locked. */ s = splsched(); thread_lock(thread); if (--thread->ref_count > 0) { thread_unlock(thread); (void) splx(s); return; } /* * Count is zero. However, the task's and processor set's * thread lists have implicit references to * the thread, and may make new ones. Their locks also * dominate the thread lock. To check for this, we * temporarily restore the one thread reference, unlock * the thread, and then lock the other structures in * the proper order. */ thread->ref_count = 1; thread_unlock(thread); (void) splx(s); pset = thread->processor_set; pset_lock(pset); #if MACH_HOST /* * The thread might have moved. */ while (pset != thread->processor_set) { pset_unlock(pset); pset = thread->processor_set; pset_lock(pset); } #endif /* MACH_HOST */ task = thread->task; task_lock(task); s = splsched(); thread_lock(thread); if (--thread->ref_count > 0) { /* * Task or processor_set made extra reference. */ thread_unlock(thread); (void) splx(s); task_unlock(task); pset_unlock(pset); return; } /* * Thread has no references - we can remove it. */ /* * Remove pending timeouts. */ reset_timeout_check(&thread->timer); reset_timeout_check(&thread->depress_timer); thread->depress_priority = -1; /* * Accumulate times for dead threads in task. */ thread_read_times(thread, &user_time, &system_time); time_value_add(&task->total_user_time, &user_time); time_value_add(&task->total_system_time, &system_time); /* * Remove thread from task list and processor_set threads list. */ task->thread_count--; queue_remove(&task->thread_list, thread, thread_t, thread_list); pset_remove_thread(pset, thread); thread_unlock(thread); /* no more references - safe */ (void) splx(s); task_unlock(task); pset_unlock(pset); pset_deallocate(pset); /* * A couple of quick sanity checks */ if (thread == current_thread()) { panic("thread deallocating itself"); } if ((thread->state & ~(TH_RUN | TH_HALTED | TH_SWAPPED)) != TH_SUSP) panic("unstopped thread destroyed!"); /* * Deallocate the task reference, since we know the thread * is not running. */ task_deallocate(thread->task); /* may block */ /* * Clean up any machine-dependent resources. */ if ((thread->state & TH_SWAPPED) == 0) { splsched(); stack_free(thread); (void) splx(s); thread_deallocate_stack++; } /* * Rattle the event count machinery (gag) */ evc_notify_abort(thread); pcb_terminate(thread); kmem_cache_free(&thread_cache, (vm_offset_t) thread); } void thread_reference( thread_t thread) { spl_t s; if (thread == THREAD_NULL) return; s = splsched(); thread_lock(thread); thread->ref_count++; thread_unlock(thread); (void) splx(s); } /* * thread_terminate: * * Permanently stop execution of the specified thread. * * A thread to be terminated must be allowed to clean up any state * that it has before it exits. The thread is broken out of any * wait condition that it is in, and signalled to exit. It then * cleans up its state and calls thread_halt_self on its way out of * the kernel. The caller waits for the thread to halt, terminates * its IPC state, and then deallocates it. * * If the caller is the current thread, it must still exit the kernel * to clean up any state (thread and port references, messages, etc). * When it exits the kernel, it then terminates its IPC state and * queues itself for the reaper thread, which will wait for the thread * to stop and then deallocate it. (A thread cannot deallocate itself, * since it needs a kernel stack to execute.) */ kern_return_t thread_terminate( thread_t thread) { thread_t cur_thread = current_thread(); task_t cur_task; spl_t s; if (thread == THREAD_NULL) return KERN_INVALID_ARGUMENT; /* * Break IPC control over the thread. */ ipc_thread_disable(thread); if (thread == cur_thread) { /* * Current thread will queue itself for reaper when * exiting kernel. */ s = splsched(); thread_lock(thread); if (thread->active) { thread->active = FALSE; thread_ast_set(thread, AST_TERMINATE); } thread_unlock(thread); ast_on(cpu_number(), AST_TERMINATE); splx(s); return KERN_SUCCESS; } /* * Lock both threads and the current task * to check termination races and prevent deadlocks. */ cur_task = current_task(); task_lock(cur_task); s = splsched(); if ((vm_offset_t)thread < (vm_offset_t)cur_thread) { thread_lock(thread); thread_lock(cur_thread); } else { thread_lock(cur_thread); thread_lock(thread); } /* * If the current thread is being terminated, help out. */ if ((!cur_task->active) || (!cur_thread->active)) { thread_unlock(cur_thread); thread_unlock(thread); (void) splx(s); task_unlock(cur_task); thread_terminate(cur_thread); return KERN_FAILURE; } thread_unlock(cur_thread); task_unlock(cur_task); /* * Terminate victim thread. */ if (!thread->active) { /* * Someone else got there first. */ thread_unlock(thread); (void) splx(s); return KERN_FAILURE; } thread->active = FALSE; thread_unlock(thread); (void) splx(s); #if MACH_HOST /* * Reassign thread to default pset if needed. */ thread_freeze(thread); if (thread->processor_set != &default_pset) { thread_doassign(thread, &default_pset, FALSE); } #endif /* MACH_HOST */ /* * Halt the victim at the clean point. */ (void) thread_halt(thread, TRUE); #if MACH_HOST thread_unfreeze(thread); #endif /* MACH_HOST */ /* * Shut down the victims IPC and deallocate its * reference to itself. */ ipc_thread_terminate(thread); thread_deallocate(thread); return KERN_SUCCESS; } kern_return_t thread_terminate_release( thread_t thread, task_t task, mach_port_t thread_name, mach_port_t reply_port, vm_offset_t address, vm_size_t size) { if (task == NULL) return KERN_INVALID_ARGUMENT; mach_port_deallocate(task->itk_space, thread_name); if (reply_port != MACH_PORT_NULL) mach_port_destroy(task->itk_space, reply_port); if ((address != 0) || (size != 0)) vm_deallocate(task->map, address, size); return thread_terminate(thread); } /* * thread_force_terminate: * * Version of thread_terminate called by task_terminate. thread is * not the current thread. task_terminate is the dominant operation, * so we can force this thread to stop. */ void thread_force_terminate( thread_t thread) { boolean_t deallocate_here; spl_t s; ipc_thread_disable(thread); #if MACH_HOST /* * Reassign thread to default pset if needed. */ thread_freeze(thread); if (thread->processor_set != &default_pset) thread_doassign(thread, &default_pset, FALSE); #endif /* MACH_HOST */ s = splsched(); thread_lock(thread); deallocate_here = thread->active; thread->active = FALSE; thread_unlock(thread); (void) splx(s); (void) thread_halt(thread, TRUE); ipc_thread_terminate(thread); #if MACH_HOST thread_unfreeze(thread); #endif /* MACH_HOST */ if (deallocate_here) thread_deallocate(thread); } /* * Halt a thread at a clean point, leaving it suspended. * * must_halt indicates whether thread must halt. * */ kern_return_t thread_halt( thread_t thread, boolean_t must_halt) { thread_t cur_thread = current_thread(); kern_return_t ret; spl_t s; if (thread == cur_thread) panic("thread_halt: trying to halt current thread."); /* * If must_halt is FALSE, then a check must be made for * a cycle of halt operations. */ if (!must_halt) { /* * Grab both thread locks. */ s = splsched(); if ((vm_offset_t)thread < (vm_offset_t)cur_thread) { thread_lock(thread); thread_lock(cur_thread); } else { thread_lock(cur_thread); thread_lock(thread); } /* * If target thread is already halted, grab a hold * on it and return. */ if (thread->state & TH_HALTED) { thread->suspend_count++; thread_unlock(cur_thread); thread_unlock(thread); (void) splx(s); return KERN_SUCCESS; } /* * If someone is trying to halt us, we have a potential * halt cycle. Break the cycle by interrupting anyone * who is trying to halt us, and causing this operation * to fail; retry logic will only retry operations * that cannot deadlock. (If must_halt is TRUE, this * operation can never cause a deadlock.) */ if (cur_thread->ast & AST_HALT) { thread_wakeup_with_result(TH_EV_WAKE_ACTIVE(cur_thread), THREAD_INTERRUPTED); thread_unlock(thread); thread_unlock(cur_thread); (void) splx(s); return KERN_FAILURE; } thread_unlock(cur_thread); } else { /* * Lock thread and check whether it is already halted. */ s = splsched(); thread_lock(thread); if (thread->state & TH_HALTED) { thread->suspend_count++; thread_unlock(thread); (void) splx(s); return KERN_SUCCESS; } } /* * Suspend thread - inline version of thread_hold() because * thread is already locked. */ thread->suspend_count++; thread->state |= TH_SUSP; /* * If someone else is halting it, wait for that to complete. * Fail if wait interrupted and must_halt is false. */ while ((thread->ast & AST_HALT) && (!(thread->state & TH_HALTED))) { thread->wake_active = TRUE; thread_sleep(TH_EV_WAKE_ACTIVE(thread), simple_lock_addr(thread->lock), TRUE); if (thread->state & TH_HALTED) { (void) splx(s); return KERN_SUCCESS; } if ((current_thread()->wait_result != THREAD_AWAKENED) && !(must_halt)) { (void) splx(s); thread_release(thread); return KERN_FAILURE; } thread_lock(thread); } /* * Otherwise, have to do it ourselves. */ thread_ast_set(thread, AST_HALT); while (TRUE) { /* * Wait for thread to stop. */ thread_unlock(thread); (void) splx(s); ret = thread_dowait(thread, must_halt); /* * If the dowait failed, so do we. Drop AST_HALT, and * wake up anyone else who might be waiting for it. */ if (ret != KERN_SUCCESS) { s = splsched(); thread_lock(thread); thread_ast_clear(thread, AST_HALT); thread_wakeup_with_result(TH_EV_WAKE_ACTIVE(thread), THREAD_INTERRUPTED); thread_unlock(thread); (void) splx(s); thread_release(thread); return ret; } /* * Clear any interruptible wait. */ clear_wait(thread, THREAD_INTERRUPTED, TRUE); /* * If the thread's at a clean point, we're done. * Don't need a lock because it really is stopped. */ if (thread->state & TH_HALTED) { return KERN_SUCCESS; } /* * If the thread is at a nice continuation, * or a continuation with a cleanup routine, * call the cleanup routine. */ if ((((thread->swap_func == mach_msg_continue) || (thread->swap_func == mach_msg_receive_continue)) && mach_msg_interrupt(thread)) || (thread->swap_func == thread_exception_return) || (thread->swap_func == thread_bootstrap_return)) { s = splsched(); thread_lock(thread); thread->state |= TH_HALTED; thread_ast_clear(thread, AST_HALT); thread_unlock(thread); splx(s); return KERN_SUCCESS; } /* * Force the thread to stop at a clean * point, and arrange to wait for it. * * Set it running, so it can notice. Override * the suspend count. We know that the thread * is suspended and not waiting. * * Since the thread may hit an interruptible wait * before it reaches a clean point, we must force it * to wake us up when it does so. This involves some * trickery: * We mark the thread SUSPENDED so that thread_block * will suspend it and wake us up. * We mark the thread RUNNING so that it will run. * We mark the thread UN-INTERRUPTIBLE (!) so that * some other thread trying to halt or suspend it won't * take it off the run queue before it runs. Since * dispatching a thread (the tail of thread_invoke) marks * the thread interruptible, it will stop at the next * context switch or interruptible wait. */ s = splsched(); thread_lock(thread); if ((thread->state & TH_SCHED_STATE) != TH_SUSP) panic("thread_halt"); thread->state |= TH_RUN | TH_UNINT; thread_setrun(thread, FALSE); /* * Continue loop and wait for thread to stop. */ } } void __attribute__((noreturn)) walking_zombie(void) { panic("the zombie walks!"); } /* * Thread calls this routine on exit from the kernel when it * notices a halt request. */ void thread_halt_self(void) { thread_t thread = current_thread(); spl_t s; if (thread->ast & AST_TERMINATE) { /* * Thread is terminating itself. Shut * down IPC, then queue it up for the * reaper thread. */ ipc_thread_terminate(thread); thread_hold(thread); s = splsched(); simple_lock(&reaper_lock); enqueue_tail(&reaper_queue, &(thread->links)); simple_unlock(&reaper_lock); thread_lock(thread); thread->state |= TH_HALTED; thread_unlock(thread); (void) splx(s); thread_wakeup((event_t)&reaper_queue); counter(c_thread_halt_self_block++); thread_block(walking_zombie); /*NOTREACHED*/ } else { /* * Thread was asked to halt - show that it * has done so. */ s = splsched(); thread_lock(thread); thread->state |= TH_HALTED; thread_ast_clear(thread, AST_HALT); thread_unlock(thread); splx(s); counter(c_thread_halt_self_block++); thread_block(thread_exception_return); /* * thread_release resets TH_HALTED. */ } } /* * thread_hold: * * Suspend execution of the specified thread. * This is a recursive-style suspension of the thread, a count of * suspends is maintained. */ void thread_hold( thread_t thread) { spl_t s; s = splsched(); thread_lock(thread); thread->suspend_count++; thread->state |= TH_SUSP; thread_unlock(thread); (void) splx(s); } /* * thread_dowait: * * Wait for a thread to actually enter stopped state. * * must_halt argument indicates if this may fail on interruption. * This is FALSE only if called from thread_abort via thread_halt. */ kern_return_t thread_dowait( thread_t thread, boolean_t must_halt) { boolean_t need_wakeup; kern_return_t ret = KERN_SUCCESS; spl_t s; if (thread == current_thread()) panic("thread_dowait"); /* * If a thread is not interruptible, it may not be suspended * until it becomes interruptible. In this case, we wait for * the thread to stop itself, and indicate that we are waiting * for it to stop so that it can wake us up when it does stop. * * If the thread is interruptible, we may be able to suspend * it immediately. There are several cases: * * 1) The thread is already stopped (trivial) * 2) The thread is runnable (marked RUN and on a run queue). * We pull it off the run queue and mark it stopped. * 3) The thread is running. We wait for it to stop. */ need_wakeup = FALSE; s = splsched(); thread_lock(thread); for (;;) { switch (thread->state & TH_SCHED_STATE) { case TH_SUSP: case TH_WAIT | TH_SUSP: /* * Thread is already suspended, or sleeping in an * interruptible wait. We win! */ break; case TH_RUN | TH_SUSP: /* * The thread is interruptible. If we can pull * it off a runq, stop it here. */ if (rem_runq(thread) != RUN_QUEUE_NULL) { thread->state &= ~TH_RUN; need_wakeup = thread->wake_active; thread->wake_active = FALSE; break; } #if NCPUS > 1 /* * The thread must be running, so make its * processor execute ast_check(). This * should cause the thread to take an ast and * context switch to suspend for us. */ cause_ast_check(thread->last_processor); #endif /* NCPUS > 1 */ /* * Fall through to wait for thread to stop. */ case TH_RUN | TH_SUSP | TH_UNINT: case TH_RUN | TH_WAIT | TH_SUSP: case TH_RUN | TH_WAIT | TH_SUSP | TH_UNINT: case TH_WAIT | TH_SUSP | TH_UNINT: /* * Wait for the thread to stop, or sleep interruptibly * (thread_block will stop it in the latter case). * Check for failure if interrupted. */ thread->wake_active = TRUE; thread_sleep(TH_EV_WAKE_ACTIVE(thread), simple_lock_addr(thread->lock), TRUE); thread_lock(thread); if ((current_thread()->wait_result != THREAD_AWAKENED) && !must_halt) { ret = KERN_FAILURE; break; } /* * Repeat loop to check thread`s state. */ continue; } /* * Thread is stopped at this point. */ break; } thread_unlock(thread); (void) splx(s); if (need_wakeup) thread_wakeup(TH_EV_WAKE_ACTIVE(thread)); return ret; } void thread_release( thread_t thread) { spl_t s; s = splsched(); thread_lock(thread); if (--thread->suspend_count == 0) { thread->state &= ~(TH_SUSP | TH_HALTED); if ((thread->state & (TH_WAIT | TH_RUN)) == 0) { /* was only suspended */ thread->state |= TH_RUN; thread_setrun(thread, TRUE); } } thread_unlock(thread); (void) splx(s); } kern_return_t thread_suspend( thread_t thread) { boolean_t hold; spl_t spl; if (thread == THREAD_NULL) return KERN_INVALID_ARGUMENT; hold = FALSE; spl = splsched(); thread_lock(thread); /* Wait for thread to get interruptible */ while (thread->state & TH_UNINT) { assert_wait(TH_EV_STATE(thread), TRUE); thread_unlock(thread); thread_block(NULL); thread_lock(thread); } if (thread->user_stop_count++ == 0) { hold = TRUE; thread->suspend_count++; thread->state |= TH_SUSP; } thread_unlock(thread); (void) splx(spl); /* * Now wait for the thread if necessary. */ if (hold) { if (thread == current_thread()) { /* * We want to call thread_block on our way out, * to stop running. */ spl = splsched(); ast_on(cpu_number(), AST_BLOCK); (void) splx(spl); } else (void) thread_dowait(thread, TRUE); } return KERN_SUCCESS; } kern_return_t thread_resume( thread_t thread) { kern_return_t ret; spl_t s; if (thread == THREAD_NULL) return KERN_INVALID_ARGUMENT; ret = KERN_SUCCESS; s = splsched(); thread_lock(thread); if (thread->user_stop_count > 0) { if (--thread->user_stop_count == 0) { if (--thread->suspend_count == 0) { thread->state &= ~(TH_SUSP | TH_HALTED); if ((thread->state & (TH_WAIT | TH_RUN)) == 0) { /* was only suspended */ thread->state |= TH_RUN; thread_setrun(thread, TRUE); } } } } else { ret = KERN_FAILURE; } thread_unlock(thread); (void) splx(s); return ret; } /* * Return thread's machine-dependent state. */ kern_return_t thread_get_state( thread_t thread, int flavor, thread_state_t old_state, /* pointer to OUT array */ natural_t *old_state_count) /*IN/OUT*/ { kern_return_t ret; if (thread == THREAD_NULL || thread == current_thread()) { return KERN_INVALID_ARGUMENT; } thread_hold(thread); (void) thread_dowait(thread, TRUE); ret = thread_getstatus(thread, flavor, old_state, old_state_count); thread_release(thread); return ret; } /* * Change thread's machine-dependent state. */ kern_return_t thread_set_state( thread_t thread, int flavor, thread_state_t new_state, natural_t new_state_count) { kern_return_t ret; if (thread == THREAD_NULL || thread == current_thread()) { return KERN_INVALID_ARGUMENT; } thread_hold(thread); (void) thread_dowait(thread, TRUE); ret = thread_setstatus(thread, flavor, new_state, new_state_count); thread_release(thread); return ret; } kern_return_t thread_info( thread_t thread, int flavor, thread_info_t thread_info_out, /* pointer to OUT array */ natural_t *thread_info_count) /*IN/OUT*/ { int state, flags; spl_t s; if (thread == THREAD_NULL) return KERN_INVALID_ARGUMENT; if (flavor == THREAD_BASIC_INFO) { thread_basic_info_t basic_info; /* Allow *thread_info_count to be one smaller than the usual amount, because creation_time is a new member that some callers might not know about. */ if (*thread_info_count < THREAD_BASIC_INFO_COUNT - 1) { return KERN_INVALID_ARGUMENT; } basic_info = (thread_basic_info_t) thread_info_out; s = splsched(); thread_lock(thread); /* * Update lazy-evaluated scheduler info because someone wants it. */ if ((thread->state & TH_RUN) == 0 && thread->sched_stamp != sched_tick) update_priority(thread); /* fill in info */ thread_read_times(thread, &basic_info->user_time, &basic_info->system_time); basic_info->base_priority = thread->priority; basic_info->cur_priority = thread->sched_pri; read_time_stamp(&thread->creation_time, &basic_info->creation_time); /* * To calculate cpu_usage, first correct for timer rate, * then for 5/8 ageing. The correction factor [3/5] is * (1/(5/8) - 1). */ basic_info->cpu_usage = thread->cpu_usage / (TIMER_RATE/TH_USAGE_SCALE); basic_info->cpu_usage = (basic_info->cpu_usage * 3) / 5; #if SIMPLE_CLOCK /* * Clock drift compensation. */ basic_info->cpu_usage = (basic_info->cpu_usage * 1000000)/sched_usec; #endif /* SIMPLE_CLOCK */ flags = 0; if (thread->state & TH_SWAPPED) flags |= TH_FLAGS_SWAPPED; if (thread->state & TH_IDLE) flags |= TH_FLAGS_IDLE; if (thread->state & TH_HALTED) state = TH_STATE_HALTED; else if (thread->state & TH_RUN) state = TH_STATE_RUNNING; else if (thread->state & TH_UNINT) state = TH_STATE_UNINTERRUPTIBLE; else if (thread->state & TH_SUSP) state = TH_STATE_STOPPED; else if (thread->state & TH_WAIT) state = TH_STATE_WAITING; else state = 0; /* ? */ basic_info->run_state = state; basic_info->flags = flags; basic_info->suspend_count = thread->user_stop_count; if (state == TH_STATE_RUNNING) basic_info->sleep_time = 0; else basic_info->sleep_time = sched_tick - thread->sched_stamp; thread_unlock(thread); splx(s); if (*thread_info_count > THREAD_BASIC_INFO_COUNT) *thread_info_count = THREAD_BASIC_INFO_COUNT; return KERN_SUCCESS; } else if (flavor == THREAD_SCHED_INFO) { thread_sched_info_t sched_info; if (*thread_info_count < THREAD_SCHED_INFO_COUNT) { return KERN_INVALID_ARGUMENT; } sched_info = (thread_sched_info_t) thread_info_out; s = splsched(); thread_lock(thread); #if MACH_FIXPRI sched_info->policy = thread->policy; if (thread->policy == POLICY_FIXEDPRI) { sched_info->data = (thread->sched_data * tick)/1000; } else { sched_info->data = 0; } #else /* MACH_FIXPRI */ sched_info->policy = POLICY_TIMESHARE; sched_info->data = 0; #endif /* MACH_FIXPRI */ sched_info->base_priority = thread->priority; sched_info->max_priority = thread->max_priority; sched_info->cur_priority = thread->sched_pri; sched_info->depressed = (thread->depress_priority >= 0); sched_info->depress_priority = thread->depress_priority; thread_unlock(thread); splx(s); *thread_info_count = THREAD_SCHED_INFO_COUNT; return KERN_SUCCESS; } return KERN_INVALID_ARGUMENT; } kern_return_t thread_abort( thread_t thread) { if (thread == THREAD_NULL || thread == current_thread()) { return KERN_INVALID_ARGUMENT; } /* * * clear it of an event wait */ evc_notify_abort(thread); /* * Try to force the thread to a clean point * If the halt operation fails return KERN_ABORTED. * ipc code will convert this to an ipc interrupted error code. */ if (thread_halt(thread, FALSE) != KERN_SUCCESS) return KERN_ABORTED; /* * If the thread was in an exception, abort that too. */ mach_msg_abort_rpc(thread); /* * Then set it going again. */ thread_release(thread); /* * Also abort any depression. */ if (thread->depress_priority != -1) thread_depress_abort(thread); return KERN_SUCCESS; } /* * thread_start: * * Start a thread at the specified routine. * The thread must be in a swapped state. */ void thread_start( thread_t thread, continuation_t start) { thread->swap_func = start; } /* * kernel_thread: * * Start up a kernel thread in the specified task. */ thread_t kernel_thread( task_t task, continuation_t start, void * arg) { kern_return_t kr; thread_t thread; kr = thread_create(task, &thread); if (kr != KERN_SUCCESS) return THREAD_NULL; /* release "extra" ref that thread_create gave us */ thread_deallocate(thread); thread_start(thread, start); thread->ith_other = arg; /* * We ensure that the kernel thread starts with a stack. * The swapin mechanism might not be operational yet. */ thread_doswapin(thread); thread->max_priority = BASEPRI_SYSTEM; thread->priority = BASEPRI_SYSTEM; thread->sched_pri = BASEPRI_SYSTEM; (void) thread_resume(thread); return thread; } /* * reaper_thread: * * This kernel thread runs forever looking for threads to destroy * (when they request that they be destroyed, of course). */ void __attribute__((noreturn)) reaper_thread_continue(void) { for (;;) { thread_t thread; spl_t s; s = splsched(); simple_lock(&reaper_lock); while ((thread = (thread_t) dequeue_head(&reaper_queue)) != THREAD_NULL) { simple_unlock(&reaper_lock); (void) splx(s); (void) thread_dowait(thread, TRUE); /* may block */ thread_deallocate(thread); /* may block */ s = splsched(); simple_lock(&reaper_lock); } assert_wait((event_t) &reaper_queue, FALSE); simple_unlock(&reaper_lock); (void) splx(s); counter(c_reaper_thread_block++); thread_block(reaper_thread_continue); } } void reaper_thread(void) { reaper_thread_continue(); /*NOTREACHED*/ } #if MACH_HOST /* * thread_assign: * * Change processor set assignment. * Caller must hold an extra reference to the thread (if this is * called directly from the ipc interface, this is an operation * in progress reference). Caller must hold no locks -- this may block. */ kern_return_t thread_assign( thread_t thread, processor_set_t new_pset) { if (thread == THREAD_NULL || new_pset == PROCESSOR_SET_NULL) { return KERN_INVALID_ARGUMENT; } thread_freeze(thread); thread_doassign(thread, new_pset, TRUE); return KERN_SUCCESS; } /* * thread_freeze: * * Freeze thread's assignment. Prelude to assigning thread. * Only one freeze may be held per thread. */ void thread_freeze( thread_t thread) { spl_t s; /* * Freeze the assignment, deferring to a prior freeze. */ s = splsched(); thread_lock(thread); while (thread->may_assign == FALSE) { thread->assign_active = TRUE; thread_sleep((event_t) &thread->assign_active, simple_lock_addr(thread->lock), FALSE); thread_lock(thread); } thread->may_assign = FALSE; thread_unlock(thread); (void) splx(s); } /* * thread_unfreeze: release freeze on thread's assignment. */ void thread_unfreeze( thread_t thread) { spl_t s; s = splsched(); thread_lock(thread); thread->may_assign = TRUE; if (thread->assign_active) { thread->assign_active = FALSE; thread_wakeup((event_t)&thread->assign_active); } thread_unlock(thread); splx(s); } /* * thread_doassign: * * Actually do thread assignment. thread_will_assign must have been * called on the thread. release_freeze argument indicates whether * to release freeze on thread. */ void thread_doassign( thread_t thread, processor_set_t new_pset, boolean_t release_freeze) { processor_set_t pset; boolean_t old_empty, new_empty; boolean_t recompute_pri = FALSE; spl_t s; /* * Check for silly no-op. */ pset = thread->processor_set; if (pset == new_pset) { if (release_freeze) thread_unfreeze(thread); return; } /* * Suspend the thread and stop it if it's not the current thread. */ thread_hold(thread); if (thread != current_thread()) (void) thread_dowait(thread, TRUE); /* * Lock both psets now, use ordering to avoid deadlocks. */ Restart: if ((vm_offset_t)pset < (vm_offset_t)new_pset) { pset_lock(pset); pset_lock(new_pset); } else { pset_lock(new_pset); pset_lock(pset); } /* * Check if new_pset is ok to assign to. If not, reassign * to default_pset. */ if (!new_pset->active) { pset_unlock(pset); pset_unlock(new_pset); new_pset = &default_pset; goto Restart; } pset_reference(new_pset); /* * Grab the thread lock and move the thread. * Then drop the lock on the old pset and the thread's * reference to it. */ s = splsched(); thread_lock(thread); thread_change_psets(thread, pset, new_pset); old_empty = pset->empty; new_empty = new_pset->empty; pset_unlock(pset); /* * Reset policy and priorities if needed. */ #if MACH_FIXPRI if (thread->policy & new_pset->policies == 0) { thread->policy = POLICY_TIMESHARE; recompute_pri = TRUE; } #endif /* MACH_FIXPRI */ if (thread->max_priority < new_pset->max_priority) { thread->max_priority = new_pset->max_priority; if (thread->priority < thread->max_priority) { thread->priority = thread->max_priority; recompute_pri = TRUE; } else { if ((thread->depress_priority >= 0) && (thread->depress_priority < thread->max_priority)) { thread->depress_priority = thread->max_priority; } } } pset_unlock(new_pset); if (recompute_pri) compute_priority(thread, TRUE); if (release_freeze) { thread->may_assign = TRUE; if (thread->assign_active) { thread->assign_active = FALSE; thread_wakeup((event_t)&thread->assign_active); } } thread_unlock(thread); splx(s); pset_deallocate(pset); /* * Figure out hold status of thread. Threads assigned to empty * psets must be held. Therefore: * If old pset was empty release its hold. * Release our hold from above unless new pset is empty. */ if (old_empty) thread_release(thread); if (!new_empty) thread_release(thread); /* * If current_thread is assigned, context switch to force * assignment to happen. This also causes hold to take * effect if the new pset is empty. */ if (thread == current_thread()) { s = splsched(); ast_on(cpu_number(), AST_BLOCK); (void) splx(s); } } #else /* MACH_HOST */ kern_return_t thread_assign( thread_t thread, processor_set_t new_pset) { return KERN_FAILURE; } #endif /* MACH_HOST */ /* * thread_assign_default: * * Special version of thread_assign for assigning threads to default * processor set. */ kern_return_t thread_assign_default( thread_t thread) { return thread_assign(thread, &default_pset); } /* * thread_get_assignment * * Return current assignment for this thread. */ kern_return_t thread_get_assignment( thread_t thread, processor_set_t *pset) { if (thread == THREAD_NULL) return KERN_INVALID_ARGUMENT; *pset = thread->processor_set; pset_reference(*pset); return KERN_SUCCESS; } /* * thread_priority: * * Set priority (and possibly max priority) for thread. */ kern_return_t thread_priority( thread_t thread, int priority, boolean_t set_max) { spl_t s; kern_return_t ret = KERN_SUCCESS; if ((thread == THREAD_NULL) || invalid_pri(priority)) return KERN_INVALID_ARGUMENT; s = splsched(); thread_lock(thread); /* * Check for violation of max priority */ if (priority < thread->max_priority) { ret = KERN_FAILURE; } else { /* * Set priorities. If a depression is in progress, * change the priority to restore. */ if (thread->depress_priority >= 0) { thread->depress_priority = priority; } else { thread->priority = priority; compute_priority(thread, TRUE); } if (set_max) thread->max_priority = priority; } thread_unlock(thread); (void) splx(s); return ret; } /* * thread_set_own_priority: * * Internal use only; sets the priority of the calling thread. * Will adjust max_priority if necessary. */ void thread_set_own_priority( int priority) { spl_t s; thread_t thread = current_thread(); s = splsched(); thread_lock(thread); if (priority < thread->max_priority) thread->max_priority = priority; thread->priority = priority; compute_priority(thread, TRUE); thread_unlock(thread); (void) splx(s); } /* * thread_max_priority: * * Reset the max priority for a thread. */ kern_return_t thread_max_priority( thread_t thread, processor_set_t pset, int max_priority) { spl_t s; kern_return_t ret = KERN_SUCCESS; if ((thread == THREAD_NULL) || (pset == PROCESSOR_SET_NULL) || invalid_pri(max_priority)) return KERN_INVALID_ARGUMENT; s = splsched(); thread_lock(thread); #if MACH_HOST /* * Check for wrong processor set. */ if (pset != thread->processor_set) { ret = KERN_FAILURE; } else { #endif /* MACH_HOST */ thread->max_priority = max_priority; /* * Reset priority if it violates new max priority */ if (max_priority > thread->priority) { thread->priority = max_priority; compute_priority(thread, TRUE); } else { if (thread->depress_priority >= 0 && max_priority > thread->depress_priority) thread->depress_priority = max_priority; } #if MACH_HOST } #endif /* MACH_HOST */ thread_unlock(thread); (void) splx(s); return ret; } /* * thread_policy: * * Set scheduling policy for thread. */ kern_return_t thread_policy( thread_t thread, int policy, int data) { #if MACH_FIXPRI kern_return_t ret = KERN_SUCCESS; int temp; spl_t s; #endif /* MACH_FIXPRI */ if ((thread == THREAD_NULL) || invalid_policy(policy)) return KERN_INVALID_ARGUMENT; #if MACH_FIXPRI s = splsched(); thread_lock(thread); /* * Check if changing policy. */ if (policy == thread->policy) { /* * Just changing data. This is meaningless for * timesharing, quantum for fixed priority (but * has no effect until current quantum runs out). */ if (policy == POLICY_FIXEDPRI) { temp = data * 1000; if (temp % tick) temp += tick; thread->sched_data = temp/tick; } } else { /* * Changing policy. Check if new policy is allowed. */ if ((thread->processor_set->policies & policy) == 0) { ret = KERN_FAILURE; } else { /* * Changing policy. Save data and calculate new * priority. */ thread->policy = policy; if (policy == POLICY_FIXEDPRI) { temp = data * 1000; if (temp % tick) temp += tick; thread->sched_data = temp/tick; } compute_priority(thread, TRUE); } } thread_unlock(thread); (void) splx(s); return ret; #else /* MACH_FIXPRI */ if (policy == POLICY_TIMESHARE) return KERN_SUCCESS; else return KERN_FAILURE; #endif /* MACH_FIXPRI */ } /* * thread_wire: * * Specify that the target thread must always be able * to run and to allocate memory. */ kern_return_t thread_wire( host_t host, thread_t thread, boolean_t wired) { spl_t s; if (host == HOST_NULL) return KERN_INVALID_ARGUMENT; if (thread == THREAD_NULL) return KERN_INVALID_ARGUMENT; /* * This implementation only works for the current thread. * See stack_privilege. */ if (thread != current_thread()) return KERN_INVALID_ARGUMENT; s = splsched(); thread_lock(thread); if (wired) { thread->vm_privilege = TRUE; stack_privilege(thread); } else { thread->vm_privilege = FALSE; /*XXX stack_unprivilege(thread); */ thread->stack_privilege = 0; } thread_unlock(thread); splx(s); return KERN_SUCCESS; } /* * thread_collect_scan: * * Attempt to free resources owned by threads. * pcb_collect doesn't do anything yet. */ void thread_collect_scan(void) { register thread_t thread, prev_thread; processor_set_t pset, prev_pset; prev_thread = THREAD_NULL; prev_pset = PROCESSOR_SET_NULL; lock_all_psets(); queue_iterate(&all_psets, pset, processor_set_t, all_psets) { pset_lock(pset); queue_iterate(&pset->threads, thread, thread_t, pset_threads) { spl_t s = splsched(); thread_lock(thread); /* * Only collect threads which are * not runnable and are swapped. */ if ((thread->state & (TH_RUN|TH_SWAPPED)) == TH_SWAPPED) { thread->ref_count++; thread_unlock(thread); (void) splx(s); pset->ref_count++; pset_unlock(pset); unlock_all_psets(); pcb_collect(thread); if (prev_thread != THREAD_NULL) thread_deallocate(prev_thread); prev_thread = thread; if (prev_pset != PROCESSOR_SET_NULL) pset_deallocate(prev_pset); prev_pset = pset; lock_all_psets(); pset_lock(pset); } else { thread_unlock(thread); (void) splx(s); } } pset_unlock(pset); } unlock_all_psets(); if (prev_thread != THREAD_NULL) thread_deallocate(prev_thread); if (prev_pset != PROCESSOR_SET_NULL) pset_deallocate(prev_pset); } boolean_t thread_collect_allowed = TRUE; unsigned thread_collect_last_tick = 0; unsigned thread_collect_max_rate = 0; /* in ticks */ /* * consider_thread_collect: * * Called by the pageout daemon when the system needs more free pages. */ void consider_thread_collect(void) { /* * By default, don't attempt thread collection more frequently * than once a second. */ if (thread_collect_max_rate == 0) thread_collect_max_rate = hz; if (thread_collect_allowed && (sched_tick > (thread_collect_last_tick + thread_collect_max_rate))) { thread_collect_last_tick = sched_tick; thread_collect_scan(); } } #if MACH_DEBUG vm_size_t stack_usage( vm_offset_t stack) { int i; for (i = 0; i < KERNEL_STACK_SIZE/sizeof(unsigned int); i++) if (((unsigned int *)stack)[i] != STACK_MARKER) break; return KERNEL_STACK_SIZE - i * sizeof(unsigned int); } /* * Machine-dependent code should call stack_init * before doing its own initialization of the stack. */ void stack_init( vm_offset_t stack) { if (stack_check_usage) { int i; for (i = 0; i < KERNEL_STACK_SIZE/sizeof(unsigned int); i++) ((unsigned int *)stack)[i] = STACK_MARKER; } } /* * Machine-dependent code should call stack_finalize * before releasing the stack memory. */ void stack_finalize( vm_offset_t stack) { if (stack_check_usage) { vm_size_t used = stack_usage(stack); simple_lock(&stack_usage_lock); if (used > stack_max_usage) stack_max_usage = used; simple_unlock(&stack_usage_lock); } } kern_return_t host_stack_usage( host_t host, vm_size_t *reservedp, unsigned int *totalp, vm_size_t *spacep, vm_size_t *residentp, vm_size_t *maxusagep, vm_offset_t *maxstackp) { natural_t total; vm_size_t maxusage; if (host == HOST_NULL) return KERN_INVALID_HOST; total = 0; /* XXX */ simple_lock(&stack_usage_lock); maxusage = stack_max_usage; simple_unlock(&stack_usage_lock); *reservedp = 0; *totalp = total; *spacep = *residentp = total * round_page(KERNEL_STACK_SIZE); *maxusagep = maxusage; *maxstackp = 0; return KERN_SUCCESS; } kern_return_t processor_set_stack_usage( processor_set_t pset, unsigned int *totalp, vm_size_t *spacep, vm_size_t *residentp, vm_size_t *maxusagep, vm_offset_t *maxstackp) { unsigned int total; vm_size_t maxusage; vm_offset_t maxstack; thread_t *threads; thread_t tmp_thread; unsigned int actual; /* this many things */ unsigned int i; vm_size_t size, size_needed; vm_offset_t addr; if (pset == PROCESSOR_SET_NULL) return KERN_INVALID_ARGUMENT; size = 0; addr = 0; for (;;) { pset_lock(pset); if (!pset->active) { pset_unlock(pset); return KERN_INVALID_ARGUMENT; } actual = pset->thread_count; /* do we have the memory we need? */ size_needed = actual * sizeof(thread_t); if (size_needed <= size) break; /* unlock the pset and allocate more memory */ pset_unlock(pset); if (size != 0) kfree(addr, size); assert(size_needed > 0); size = size_needed; addr = kalloc(size); if (addr == 0) return KERN_RESOURCE_SHORTAGE; } /* OK, have memory and the processor_set is locked & active */ threads = (thread_t *) addr; for (i = 0, tmp_thread = (thread_t) queue_first(&pset->threads); i < actual; i++, tmp_thread = (thread_t) queue_next(&tmp_thread->pset_threads)) { thread_reference(tmp_thread); threads[i] = tmp_thread; } assert(queue_end(&pset->threads, (queue_entry_t) tmp_thread)); /* can unlock processor set now that we have the thread refs */ pset_unlock(pset); /* calculate maxusage and free thread references */ total = 0; maxusage = 0; maxstack = 0; for (i = 0; i < actual; i++) { thread_t thread = threads[i]; vm_offset_t stack = 0; /* * thread->kernel_stack is only accurate if the * thread isn't swapped and is not executing. * * Of course, we don't have the appropriate locks * for these shenanigans. */ if ((thread->state & TH_SWAPPED) == 0) { int cpu; stack = thread->kernel_stack; for (cpu = 0; cpu < NCPUS; cpu++) if (active_threads[cpu] == thread) { stack = active_stacks[cpu]; break; } } if (stack != 0) { total++; if (stack_check_usage) { vm_size_t usage = stack_usage(stack); if (usage > maxusage) { maxusage = usage; maxstack = (vm_offset_t) thread; } } } thread_deallocate(thread); } if (size != 0) kfree(addr, size); *totalp = total; *residentp = *spacep = total * round_page(KERNEL_STACK_SIZE); *maxusagep = maxusage; *maxstackp = maxstack; return KERN_SUCCESS; } /* * Useful in the debugger: */ void thread_stats(void) { thread_t thread; int total = 0, rpcreply = 0; queue_iterate(&default_pset.threads, thread, thread_t, pset_threads) { total++; if (thread->ith_rpc_reply != IP_NULL) rpcreply++; } printf("%d total threads.\n", total); printf("%d using rpc_reply.\n", rpcreply); } #endif /* MACH_DEBUG */