diff options
Diffstat (limited to 'kern')
| -rw-r--r-- | kern/thread.c | 70 | ||||
| -rw-r--r-- | kern/thread.h | 31 | ||||
| -rw-r--r-- | kern/thread_i.h | 3 |
3 files changed, 96 insertions, 8 deletions
diff --git a/kern/thread.c b/kern/thread.c index 4800fa84..bd29ef84 100644 --- a/kern/thread.c +++ b/kern/thread.c @@ -646,6 +646,11 @@ thread_runq_schedule(struct thread_runq *runq) thread_clear_flag(prev, THREAD_YIELD); thread_runq_put_prev(runq, prev); + if (prev->suspend) { + prev->state = THREAD_SUSPENDED; + prev->suspend = false; + } + if (prev->state != THREAD_RUNNING) { thread_runq_remove(runq, prev); @@ -1854,6 +1859,7 @@ thread_init(struct thread *thread, void *stack, turnstile_td_init(&thread->turnstile_td); thread->propagate_priority = false; + thread->suspend = false; thread->preempt_level = THREAD_SUSPEND_PREEMPT_LEVEL; thread->pin_level = 0; thread->intr_level = 0; @@ -2480,7 +2486,7 @@ thread_join(struct thread *thread) } static int -thread_wakeup_common(struct thread *thread, int error) +thread_wakeup_common(struct thread *thread, int error, bool resume) { struct thread_runq *runq; unsigned long flags; @@ -2500,7 +2506,8 @@ thread_wakeup_common(struct thread *thread, int error) } else { runq = thread_lock_runq(thread, &flags); - if (thread->state == THREAD_RUNNING) { + if ((thread->state == THREAD_RUNNING) + || ((thread->state == THREAD_SUSPENDED) && !resume)) { thread_unlock_runq(runq, flags); return EINVAL; } @@ -2534,7 +2541,7 @@ thread_wakeup_common(struct thread *thread, int error) int thread_wakeup(struct thread *thread) { - return thread_wakeup_common(thread, 0); + return thread_wakeup_common(thread, 0, false); } struct thread_timeout_waiter { @@ -2548,7 +2555,7 @@ thread_timeout(struct timer *timer) struct thread_timeout_waiter *waiter; waiter = structof(timer, struct thread_timeout_waiter, timer); - thread_wakeup_common(waiter->thread, ETIMEDOUT); + thread_wakeup_common(waiter->thread, ETIMEDOUT, false); } static int @@ -2613,6 +2620,59 @@ thread_timedsleep(struct spinlock *interlock, const void *wchan_addr, return thread_sleep_common(interlock, wchan_addr, wchan_desc, true, ticks); } +int +thread_suspend(struct thread *thread) +{ + struct thread_runq *runq; + unsigned long flags; + int error; + + if (thread == NULL) { + return EINVAL; + } + + thread_preempt_disable(); + runq = thread_lock_runq(thread, &flags); + + if ((thread == runq->idler) || (thread == runq->balancer)) { + error = EINVAL; + goto done; + } else if ((thread->state == THREAD_SUSPENDED) || (thread->suspend)) { + error = EAGAIN; + goto done; + } + + if (thread->state == THREAD_SLEEPING) { + thread->state = THREAD_SUSPENDED; + } else if (thread != runq->current) { + thread->state = THREAD_SUSPENDED; + thread_runq_remove(runq, thread); + } else { + thread->suspend = true; + + if (runq == thread_runq_local()) { + runq = thread_runq_schedule(runq); + } else { + thread_set_flag(thread, THREAD_YIELD); + cpu_send_thread_schedule(thread_runq_cpu(runq)); + } + } + + error = 0; + +done: + thread_unlock_runq(runq, flags); + thread_preempt_enable(); + + return error; +} + +int +thread_resume(struct thread *thread) +{ + return thread_wakeup_common(thread, 0, true); +} + void thread_delay(uint64_t ticks, bool absolute) { @@ -2753,6 +2813,8 @@ thread_state_to_chr(unsigned int state) return 'S'; case THREAD_DEAD: return 'Z'; + case THREAD_SUSPENDED: + return 'T'; default: panic("thread: unknown state"); } diff --git a/kern/thread.h b/kern/thread.h index 787fc083..41cd6a5b 100644 --- a/kern/thread.h +++ b/kern/thread.h @@ -77,9 +77,10 @@ struct thread_sched_data { /* * Thread states. */ -#define THREAD_RUNNING 0 -#define THREAD_SLEEPING 1 -#define THREAD_DEAD 2 +#define THREAD_RUNNING 0 +#define THREAD_SLEEPING 1 +#define THREAD_DEAD 2 +#define THREAD_SUSPENDED 3 /* * Scheduling policies. @@ -237,13 +238,35 @@ int thread_timedsleep(struct spinlock *interlock, const void *wchan_addr, * Schedule a thread for execution on a processor. * * If the target thread is NULL, the calling thread, or already in the - * running state, no action is performed and EINVAL is returned. + * running state, or in the suspended state, no action is performed and + * EINVAL is returned. * * TODO Describe memory ordering with regard to thread_sleep(). */ int thread_wakeup(struct thread *thread); /* + * Suspend a thread. + * + * A suspended thread may only be resumed by calling thread_resume(). + * + * This operation is asynchronous, i.e. the caller must not expect the target + * thread to be suspended on return. + * + * If attempting to suspend core system threads, the request is ignored and + * EINVAL is returned. + */ +int thread_suspend(struct thread *thread); + +/* + * Resume a thread. + * + * This call is equivalent to thread_wakeup(), with the exception that + * it may also wake up suspended threads. + */ +int thread_resume(struct thread *thread); + +/* * Suspend execution of the calling thread. */ void thread_delay(uint64_t ticks, bool absolute); diff --git a/kern/thread_i.h b/kern/thread_i.h index 57871cd0..21f92a29 100644 --- a/kern/thread_i.h +++ b/kern/thread_i.h @@ -139,6 +139,9 @@ struct thread { */ bool boosted; /* (r,t) */ + /* True if the thread is marked to suspend */ + bool suspend; /* (r) */ + union { struct thread_rt_data rt_data; /* (r) */ struct thread_fs_data fs_data; /* (r) */ |