* UCRL-CODE-235197
*
* This file is part of the SPL, Solaris Porting Layer.
- * For details, see <http://github.com/behlendorf/spl/>.
+ * For details, see <http://zfsonlinux.org/>.
*
* The SPL is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
#include <sys/taskq.h>
#include <sys/kmem.h>
-#ifdef DEBUG_SUBSYSTEM
-#undef DEBUG_SUBSYSTEM
-#endif
+int spl_taskq_thread_bind = 0;
+module_param(spl_taskq_thread_bind, int, 0644);
+MODULE_PARM_DESC(spl_taskq_thread_bind, "Bind taskq thread to CPU by default");
-#define DEBUG_SUBSYSTEM S_TASKQ
+
+int spl_taskq_thread_dynamic = 1;
+module_param(spl_taskq_thread_dynamic, int, 0644);
+MODULE_PARM_DESC(spl_taskq_thread_dynamic, "Allow dynamic taskq threads");
+
+int spl_taskq_thread_priority = 1;
+module_param(spl_taskq_thread_priority, int, 0644);
+MODULE_PARM_DESC(spl_taskq_thread_priority,
+ "Allow non-default priority for taskq threads");
+
+int spl_taskq_thread_sequential = 4;
+module_param(spl_taskq_thread_sequential, int, 0644);
+MODULE_PARM_DESC(spl_taskq_thread_sequential,
+ "Create new taskq threads after N sequential tasks");
/* Global system-wide dynamic task queue available for all consumers */
taskq_t *system_taskq;
EXPORT_SYMBOL(system_taskq);
-typedef struct spl_task {
- spinlock_t t_lock;
- struct list_head t_list;
- taskqid_t t_id;
- task_func_t *t_func;
- void *t_arg;
-} spl_task_t;
+/* Private dedicated taskq for creating new taskq threads on demand. */
+static taskq_t *dynamic_taskq;
+static taskq_thread_t *taskq_thread_create(taskq_t *);
+
+static int
+task_km_flags(uint_t flags)
+{
+ if (flags & TQ_NOSLEEP)
+ return KM_NOSLEEP;
+
+ if (flags & TQ_PUSHPAGE)
+ return KM_PUSHPAGE;
+
+ return KM_SLEEP;
+}
/*
* NOTE: Must be called with tq->tq_lock held, returns a list_t which
* is not attached to the free, work, or pending taskq lists.
*/
-static spl_task_t *
-task_alloc(taskq_t *tq, uint_t flags)
+static taskq_ent_t *
+task_alloc(taskq_t *tq, uint_t flags, unsigned long *irqflags)
{
- spl_task_t *t;
- int count = 0;
- ENTRY;
+ taskq_ent_t *t;
+ int count = 0;
- ASSERT(tq);
- ASSERT(flags & (TQ_SLEEP | TQ_NOSLEEP)); /* One set */
- ASSERT(!((flags & TQ_SLEEP) && (flags & TQ_NOSLEEP))); /* Not both */
- ASSERT(spin_is_locked(&tq->tq_lock));
+ ASSERT(tq);
+ ASSERT(spin_is_locked(&tq->tq_lock));
retry:
- /* Acquire spl_task_t's from free list if available */
- if (!list_empty(&tq->tq_free_list) && !(flags & TQ_NEW)) {
- t = list_entry(tq->tq_free_list.next, spl_task_t, t_list);
- list_del_init(&t->t_list);
- RETURN(t);
- }
-
- /* Free list is empty and memory allocations are prohibited */
- if (flags & TQ_NOALLOC)
- RETURN(NULL);
-
- /* Hit maximum spl_task_t pool size */
- if (tq->tq_nalloc >= tq->tq_maxalloc) {
- if (flags & TQ_NOSLEEP)
- RETURN(NULL);
-
- /* Sleep periodically polling the free list for an available
- * spl_task_t. If a full second passes and we have not found
- * one gives up and return a NULL to the caller. */
- if (flags & TQ_SLEEP) {
- spin_unlock_irqrestore(&tq->tq_lock, tq->tq_lock_flags);
- schedule_timeout(HZ / 100);
- spin_lock_irqsave(&tq->tq_lock, tq->tq_lock_flags);
- if (count < 100)
- GOTO(retry, count++);
-
- RETURN(NULL);
- }
-
- /* Unreachable, TQ_SLEEP or TQ_NOSLEEP */
- SBUG();
- }
-
- spin_unlock_irqrestore(&tq->tq_lock, tq->tq_lock_flags);
- t = kmem_alloc(sizeof(spl_task_t), flags & (TQ_SLEEP | TQ_NOSLEEP));
- spin_lock_irqsave(&tq->tq_lock, tq->tq_lock_flags);
+ /* Acquire taskq_ent_t's from free list if available */
+ if (!list_empty(&tq->tq_free_list) && !(flags & TQ_NEW)) {
+ t = list_entry(tq->tq_free_list.next, taskq_ent_t, tqent_list);
+
+ ASSERT(!(t->tqent_flags & TQENT_FLAG_PREALLOC));
+ ASSERT(!(t->tqent_flags & TQENT_FLAG_CANCEL));
+ ASSERT(!timer_pending(&t->tqent_timer));
+
+ list_del_init(&t->tqent_list);
+ return (t);
+ }
+
+ /* Free list is empty and memory allocations are prohibited */
+ if (flags & TQ_NOALLOC)
+ return (NULL);
+
+ /* Hit maximum taskq_ent_t pool size */
+ if (tq->tq_nalloc >= tq->tq_maxalloc) {
+ if (flags & TQ_NOSLEEP)
+ return (NULL);
+
+ /*
+ * Sleep periodically polling the free list for an available
+ * taskq_ent_t. Dispatching with TQ_SLEEP should always succeed
+ * but we cannot block forever waiting for an taskq_ent_t to
+ * show up in the free list, otherwise a deadlock can happen.
+ *
+ * Therefore, we need to allocate a new task even if the number
+ * of allocated tasks is above tq->tq_maxalloc, but we still
+ * end up delaying the task allocation by one second, thereby
+ * throttling the task dispatch rate.
+ */
+ spin_unlock_irqrestore(&tq->tq_lock, *irqflags);
+ schedule_timeout(HZ / 100);
+ spin_lock_irqsave_nested(&tq->tq_lock, *irqflags,
+ tq->tq_lock_class);
+ if (count < 100) {
+ count++;
+ goto retry;
+ }
+ }
+
+ spin_unlock_irqrestore(&tq->tq_lock, *irqflags);
+ t = kmem_alloc(sizeof(taskq_ent_t), task_km_flags(flags));
+ spin_lock_irqsave_nested(&tq->tq_lock, *irqflags, tq->tq_lock_class);
if (t) {
- spin_lock_init(&t->t_lock);
- INIT_LIST_HEAD(&t->t_list);
- t->t_id = 0;
- t->t_func = NULL;
- t->t_arg = NULL;
+ taskq_init_ent(t);
tq->tq_nalloc++;
}
- RETURN(t);
+ return (t);
}
/*
- * NOTE: Must be called with tq->tq_lock held, expects the spl_task_t
+ * NOTE: Must be called with tq->tq_lock held, expects the taskq_ent_t
* to already be removed from the free, work, or pending taskq lists.
*/
static void
-task_free(taskq_t *tq, spl_task_t *t)
+task_free(taskq_t *tq, taskq_ent_t *t)
{
- ENTRY;
-
- ASSERT(tq);
- ASSERT(t);
+ ASSERT(tq);
+ ASSERT(t);
ASSERT(spin_is_locked(&tq->tq_lock));
- ASSERT(list_empty(&t->t_list));
-
- kmem_free(t, sizeof(spl_task_t));
- tq->tq_nalloc--;
+ ASSERT(list_empty(&t->tqent_list));
+ ASSERT(!timer_pending(&t->tqent_timer));
- EXIT;
+ kmem_free(t, sizeof(taskq_ent_t));
+ tq->tq_nalloc--;
}
/*
* NOTE: Must be called with tq->tq_lock held, either destroys the
- * spl_task_t if too many exist or moves it to the free list for later use.
+ * taskq_ent_t if too many exist or moves it to the free list for later use.
*/
static void
-task_done(taskq_t *tq, spl_task_t *t)
+task_done(taskq_t *tq, taskq_ent_t *t)
{
- ENTRY;
ASSERT(tq);
ASSERT(t);
ASSERT(spin_is_locked(&tq->tq_lock));
- list_del_init(&t->t_list);
+ /* Wake tasks blocked in taskq_wait_id() */
+ wake_up_all(&t->tqent_waitq);
- if (tq->tq_nalloc <= tq->tq_minalloc) {
- t->t_id = 0;
- t->t_func = NULL;
- t->t_arg = NULL;
- list_add_tail(&t->t_list, &tq->tq_free_list);
+ list_del_init(&t->tqent_list);
+
+ if (tq->tq_nalloc <= tq->tq_minalloc) {
+ t->tqent_id = 0;
+ t->tqent_func = NULL;
+ t->tqent_arg = NULL;
+ t->tqent_flags = 0;
+
+ list_add_tail(&t->tqent_list, &tq->tq_free_list);
} else {
task_free(tq, t);
}
+}
- EXIT;
+/*
+ * When a delayed task timer expires remove it from the delay list and
+ * add it to the priority list in order for immediate processing.
+ */
+static void
+task_expire(unsigned long data)
+{
+ taskq_ent_t *w, *t = (taskq_ent_t *)data;
+ taskq_t *tq = t->tqent_taskq;
+ struct list_head *l;
+ unsigned long flags;
+
+ spin_lock_irqsave_nested(&tq->tq_lock, flags, tq->tq_lock_class);
+
+ if (t->tqent_flags & TQENT_FLAG_CANCEL) {
+ ASSERT(list_empty(&t->tqent_list));
+ spin_unlock_irqrestore(&tq->tq_lock, flags);
+ return;
+ }
+
+ /*
+ * The priority list must be maintained in strict task id order
+ * from lowest to highest for lowest_id to be easily calculable.
+ */
+ list_del(&t->tqent_list);
+ list_for_each_prev(l, &tq->tq_prio_list) {
+ w = list_entry(l, taskq_ent_t, tqent_list);
+ if (w->tqent_id < t->tqent_id) {
+ list_add(&t->tqent_list, l);
+ break;
+ }
+ }
+ if (l == &tq->tq_prio_list)
+ list_add(&t->tqent_list, &tq->tq_prio_list);
+
+ spin_unlock_irqrestore(&tq->tq_lock, flags);
+
+ wake_up(&tq->tq_work_waitq);
}
/*
- * As tasks are submitted to the task queue they are assigned a
- * monotonically increasing taskqid and added to the tail of the
- * pending list. As worker threads become available the tasks are
- * removed from the head of the pending list and added to the tail
- * of the work list. Finally, as tasks complete they are removed
- * from the work list. This means that the pending and work lists
- * are always kept sorted by taskqid. Thus the lowest outstanding
- * incomplete taskqid can be determined simply by checking the min
- * taskqid for each head item on the pending and work list. This
- * value is stored in tq->tq_lowest_id and only updated to the new
- * lowest id when the previous lowest id completes. All taskqids
- * lower than tq->tq_lowest_id must have completed. It is also
- * possible larger taskqid's have completed because they may be
- * processed in parallel by several worker threads. However, this
- * is not a problem because the behavior of taskq_wait_id() is to
- * block until all previously submitted taskqid's have completed.
+ * Returns the lowest incomplete taskqid_t. The taskqid_t may
+ * be queued on the pending list, on the priority list, on the
+ * delay list, or on the work list currently being handled, but
+ * it is not 100% complete yet.
+ */
+static taskqid_t
+taskq_lowest_id(taskq_t *tq)
+{
+ taskqid_t lowest_id = tq->tq_next_id;
+ taskq_ent_t *t;
+ taskq_thread_t *tqt;
+
+ ASSERT(tq);
+ ASSERT(spin_is_locked(&tq->tq_lock));
+
+ if (!list_empty(&tq->tq_pend_list)) {
+ t = list_entry(tq->tq_pend_list.next, taskq_ent_t, tqent_list);
+ lowest_id = MIN(lowest_id, t->tqent_id);
+ }
+
+ if (!list_empty(&tq->tq_prio_list)) {
+ t = list_entry(tq->tq_prio_list.next, taskq_ent_t, tqent_list);
+ lowest_id = MIN(lowest_id, t->tqent_id);
+ }
+
+ if (!list_empty(&tq->tq_delay_list)) {
+ t = list_entry(tq->tq_delay_list.next, taskq_ent_t, tqent_list);
+ lowest_id = MIN(lowest_id, t->tqent_id);
+ }
+
+ if (!list_empty(&tq->tq_active_list)) {
+ tqt = list_entry(tq->tq_active_list.next, taskq_thread_t,
+ tqt_active_list);
+ ASSERT(tqt->tqt_id != 0);
+ lowest_id = MIN(lowest_id, tqt->tqt_id);
+ }
+
+ return (lowest_id);
+}
+
+/*
+ * Insert a task into a list keeping the list sorted by increasing taskqid.
+ */
+static void
+taskq_insert_in_order(taskq_t *tq, taskq_thread_t *tqt)
+{
+ taskq_thread_t *w;
+ struct list_head *l;
+
+ ASSERT(tq);
+ ASSERT(tqt);
+ ASSERT(spin_is_locked(&tq->tq_lock));
+
+ list_for_each_prev(l, &tq->tq_active_list) {
+ w = list_entry(l, taskq_thread_t, tqt_active_list);
+ if (w->tqt_id < tqt->tqt_id) {
+ list_add(&tqt->tqt_active_list, l);
+ break;
+ }
+ }
+ if (l == &tq->tq_active_list)
+ list_add(&tqt->tqt_active_list, &tq->tq_active_list);
+}
+
+/*
+ * Find and return a task from the given list if it exists. The list
+ * must be in lowest to highest task id order.
+ */
+static taskq_ent_t *
+taskq_find_list(taskq_t *tq, struct list_head *lh, taskqid_t id)
+{
+ struct list_head *l;
+ taskq_ent_t *t;
+
+ ASSERT(spin_is_locked(&tq->tq_lock));
+
+ list_for_each(l, lh) {
+ t = list_entry(l, taskq_ent_t, tqent_list);
+
+ if (t->tqent_id == id)
+ return (t);
+
+ if (t->tqent_id > id)
+ break;
+ }
+
+ return (NULL);
+}
+
+/*
+ * Find an already dispatched task given the task id regardless of what
+ * state it is in. If a task is still pending or executing it will be
+ * returned and 'active' set appropriately. If the task has already
+ * been run then NULL is returned.
+ */
+static taskq_ent_t *
+taskq_find(taskq_t *tq, taskqid_t id, int *active)
+{
+ taskq_thread_t *tqt;
+ struct list_head *l;
+ taskq_ent_t *t;
+
+ ASSERT(spin_is_locked(&tq->tq_lock));
+ *active = 0;
+
+ t = taskq_find_list(tq, &tq->tq_delay_list, id);
+ if (t)
+ return (t);
+
+ t = taskq_find_list(tq, &tq->tq_prio_list, id);
+ if (t)
+ return (t);
+
+ t = taskq_find_list(tq, &tq->tq_pend_list, id);
+ if (t)
+ return (t);
+
+ list_for_each(l, &tq->tq_active_list) {
+ tqt = list_entry(l, taskq_thread_t, tqt_active_list);
+ if (tqt->tqt_id == id) {
+ t = tqt->tqt_task;
+ *active = 1;
+ return (t);
+ }
+ }
+
+ return (NULL);
+}
+
+/*
+ * Theory for the taskq_wait_id(), taskq_wait_outstanding(), and
+ * taskq_wait() functions below.
+ *
+ * Taskq waiting is accomplished by tracking the lowest outstanding task
+ * id and the next available task id. As tasks are dispatched they are
+ * added to the tail of the pending, priority, or delay lists. As worker
+ * threads become available the tasks are removed from the heads of these
+ * lists and linked to the worker threads. This ensures the lists are
+ * kept sorted by lowest to highest task id.
+ *
+ * Therefore the lowest outstanding task id can be quickly determined by
+ * checking the head item from all of these lists. This value is stored
+ * with the taskq as the lowest id. It only needs to be recalculated when
+ * either the task with the current lowest id completes or is canceled.
*
- * XXX: Taskqid_t wrapping is not handled. However, taskqid_t's are
- * 64-bit values so even if a taskq is processing 2^24 (16,777,216)
- * taskqid_ts per second it will still take 2^40 seconds, 34,865 years,
- * before the wrap occurs. I can live with that for now.
+ * By blocking until the lowest task id exceeds the passed task id the
+ * taskq_wait_outstanding() function can be easily implemented. Similarly,
+ * by blocking until the lowest task id matches the next task id taskq_wait()
+ * can be implemented.
+ *
+ * Callers should be aware that when there are multiple worked threads it
+ * is possible for larger task ids to complete before smaller ones. Also
+ * when the taskq contains delay tasks with small task ids callers may
+ * block for a considerable length of time waiting for them to expire and
+ * execute.
+ */
+static int
+taskq_wait_id_check(taskq_t *tq, taskqid_t id)
+{
+ int active = 0;
+ int rc;
+ unsigned long flags;
+
+ spin_lock_irqsave_nested(&tq->tq_lock, flags, tq->tq_lock_class);
+ rc = (taskq_find(tq, id, &active) == NULL);
+ spin_unlock_irqrestore(&tq->tq_lock, flags);
+
+ return (rc);
+}
+
+/*
+ * The taskq_wait_id() function blocks until the passed task id completes.
+ * This does not guarantee that all lower task ids have completed.
*/
+void
+taskq_wait_id(taskq_t *tq, taskqid_t id)
+{
+ wait_event(tq->tq_wait_waitq, taskq_wait_id_check(tq, id));
+}
+EXPORT_SYMBOL(taskq_wait_id);
+
static int
-taskq_wait_check(taskq_t *tq, taskqid_t id)
+taskq_wait_outstanding_check(taskq_t *tq, taskqid_t id)
{
int rc;
+ unsigned long flags;
- spin_lock_irqsave(&tq->tq_lock, tq->tq_lock_flags);
+ spin_lock_irqsave_nested(&tq->tq_lock, flags, tq->tq_lock_class);
rc = (id < tq->tq_lowest_id);
- spin_unlock_irqrestore(&tq->tq_lock, tq->tq_lock_flags);
+ spin_unlock_irqrestore(&tq->tq_lock, flags);
- RETURN(rc);
+ return (rc);
}
+/*
+ * The taskq_wait_outstanding() function will block until all tasks with a
+ * lower taskqid than the passed 'id' have been completed. Note that all
+ * task id's are assigned monotonically at dispatch time. Zero may be
+ * passed for the id to indicate all tasks dispatch up to this point,
+ * but not after, should be waited for.
+ */
void
-__taskq_wait_id(taskq_t *tq, taskqid_t id)
+taskq_wait_outstanding(taskq_t *tq, taskqid_t id)
{
- ENTRY;
- ASSERT(tq);
+ wait_event(tq->tq_wait_waitq,
+ taskq_wait_outstanding_check(tq, id ? id : tq->tq_next_id - 1));
+}
+EXPORT_SYMBOL(taskq_wait_outstanding);
- wait_event(tq->tq_wait_waitq, taskq_wait_check(tq, id));
+static int
+taskq_wait_check(taskq_t *tq)
+{
+ int rc;
+ unsigned long flags;
- EXIT;
+ spin_lock_irqsave_nested(&tq->tq_lock, flags, tq->tq_lock_class);
+ rc = (tq->tq_lowest_id == tq->tq_next_id);
+ spin_unlock_irqrestore(&tq->tq_lock, flags);
+
+ return (rc);
}
-EXPORT_SYMBOL(__taskq_wait_id);
+/*
+ * The taskq_wait() function will block until the taskq is empty.
+ * This means that if a taskq re-dispatches work to itself taskq_wait()
+ * callers will block indefinitely.
+ */
void
-__taskq_wait(taskq_t *tq)
+taskq_wait(taskq_t *tq)
+{
+ wait_event(tq->tq_wait_waitq, taskq_wait_check(tq));
+}
+EXPORT_SYMBOL(taskq_wait);
+
+static int
+taskq_member_impl(taskq_t *tq, void *t)
{
- taskqid_t id;
- ENTRY;
+ struct list_head *l;
+ taskq_thread_t *tqt;
+ int found = 0;
+
ASSERT(tq);
+ ASSERT(t);
+ ASSERT(spin_is_locked(&tq->tq_lock));
- /* Wait for the largest outstanding taskqid */
- spin_lock_irqsave(&tq->tq_lock, tq->tq_lock_flags);
- id = tq->tq_next_id - 1;
- spin_unlock_irqrestore(&tq->tq_lock, tq->tq_lock_flags);
+ list_for_each(l, &tq->tq_thread_list) {
+ tqt = list_entry(l, taskq_thread_t, tqt_thread_list);
+ if (tqt->tqt_thread == (struct task_struct *)t) {
+ found = 1;
+ break;
+ }
+ }
+ return (found);
+}
- __taskq_wait_id(tq, id);
+int
+taskq_member(taskq_t *tq, void *t)
+{
+ int found;
+ unsigned long flags;
- EXIT;
+ spin_lock_irqsave_nested(&tq->tq_lock, flags, tq->tq_lock_class);
+ found = taskq_member_impl(tq, t);
+ spin_unlock_irqrestore(&tq->tq_lock, flags);
+ return (found);
}
-EXPORT_SYMBOL(__taskq_wait);
+EXPORT_SYMBOL(taskq_member);
+/*
+ * Cancel an already dispatched task given the task id. Still pending tasks
+ * will be immediately canceled, and if the task is active the function will
+ * block until it completes. Preallocated tasks which are canceled must be
+ * freed by the caller.
+ */
int
-__taskq_member(taskq_t *tq, void *t)
+taskq_cancel_id(taskq_t *tq, taskqid_t id)
{
- int i;
- ENTRY;
+ taskq_ent_t *t;
+ int active = 0;
+ int rc = ENOENT;
+ unsigned long flags;
ASSERT(tq);
- ASSERT(t);
- for (i = 0; i < tq->tq_nthreads; i++)
- if (tq->tq_threads[i] == (struct task_struct *)t)
- RETURN(1);
+ spin_lock_irqsave_nested(&tq->tq_lock, flags, tq->tq_lock_class);
+ t = taskq_find(tq, id, &active);
+ if (t && !active) {
+ list_del_init(&t->tqent_list);
+ t->tqent_flags |= TQENT_FLAG_CANCEL;
+
+ /*
+ * When canceling the lowest outstanding task id we
+ * must recalculate the new lowest outstanding id.
+ */
+ if (tq->tq_lowest_id == t->tqent_id) {
+ tq->tq_lowest_id = taskq_lowest_id(tq);
+ ASSERT3S(tq->tq_lowest_id, >, t->tqent_id);
+ }
+
+ /*
+ * The task_expire() function takes the tq->tq_lock so drop
+ * drop the lock before synchronously cancelling the timer.
+ */
+ if (timer_pending(&t->tqent_timer)) {
+ spin_unlock_irqrestore(&tq->tq_lock, flags);
+ del_timer_sync(&t->tqent_timer);
+ spin_lock_irqsave_nested(&tq->tq_lock, flags,
+ tq->tq_lock_class);
+ }
+
+ if (!(t->tqent_flags & TQENT_FLAG_PREALLOC))
+ task_done(tq, t);
+
+ rc = 0;
+ }
+ spin_unlock_irqrestore(&tq->tq_lock, flags);
+
+ if (active) {
+ taskq_wait_id(tq, id);
+ rc = EBUSY;
+ }
- RETURN(0);
+ return (rc);
}
-EXPORT_SYMBOL(__taskq_member);
+EXPORT_SYMBOL(taskq_cancel_id);
+
+static int taskq_thread_spawn(taskq_t *tq);
taskqid_t
-__taskq_dispatch(taskq_t *tq, task_func_t func, void *arg, uint_t flags)
+taskq_dispatch(taskq_t *tq, task_func_t func, void *arg, uint_t flags)
{
- spl_task_t *t;
+ taskq_ent_t *t;
taskqid_t rc = 0;
- ENTRY;
-
- ASSERT(tq);
- ASSERT(func);
+ unsigned long irqflags;
- /* Solaris assumes TQ_SLEEP if not passed explicitly */
- if (!(flags & (TQ_SLEEP | TQ_NOSLEEP)))
- flags |= TQ_SLEEP;
-
- if (unlikely(in_atomic() && (flags & TQ_SLEEP))) {
- CERROR("May schedule while atomic: %s/0x%08x/%d\n",
- current->comm, preempt_count(), current->pid);
- SBUG();
- }
+ ASSERT(tq);
+ ASSERT(func);
- spin_lock_irqsave(&tq->tq_lock, tq->tq_lock_flags);
+ spin_lock_irqsave_nested(&tq->tq_lock, irqflags, tq->tq_lock_class);
/* Taskq being destroyed and all tasks drained */
- if (!(tq->tq_flags & TQ_ACTIVE))
- GOTO(out, rc = 0);
+ if (!(tq->tq_flags & TASKQ_ACTIVE))
+ goto out;
/* Do not queue the task unless there is idle thread for it */
ASSERT(tq->tq_nactive <= tq->tq_nthreads);
if ((flags & TQ_NOQUEUE) && (tq->tq_nactive == tq->tq_nthreads))
- GOTO(out, rc = 0);
+ goto out;
- if ((t = task_alloc(tq, flags)) == NULL)
- GOTO(out, rc = 0);
+ if ((t = task_alloc(tq, flags, &irqflags)) == NULL)
+ goto out;
- spin_lock(&t->t_lock);
+ spin_lock(&t->tqent_lock);
- /* Queue to the head instead of the tail */
+ /* Queue to the priority list instead of the pending list */
if (flags & TQ_FRONT)
- list_add(&t->t_list, &tq->tq_pend_list);
+ list_add_tail(&t->tqent_list, &tq->tq_prio_list);
else
- list_add_tail(&t->t_list, &tq->tq_pend_list);
+ list_add_tail(&t->tqent_list, &tq->tq_pend_list);
- t->t_id = rc = tq->tq_next_id;
+ t->tqent_id = rc = tq->tq_next_id;
tq->tq_next_id++;
- t->t_func = func;
- t->t_arg = arg;
- spin_unlock(&t->t_lock);
+ t->tqent_func = func;
+ t->tqent_arg = arg;
+ t->tqent_taskq = tq;
+ t->tqent_timer.data = 0;
+ t->tqent_timer.function = NULL;
+ t->tqent_timer.expires = 0;
+
+ ASSERT(!(t->tqent_flags & TQENT_FLAG_PREALLOC));
+
+ spin_unlock(&t->tqent_lock);
wake_up(&tq->tq_work_waitq);
out:
- spin_unlock_irqrestore(&tq->tq_lock, tq->tq_lock_flags);
- RETURN(rc);
+ /* Spawn additional taskq threads if required. */
+ if (tq->tq_nactive == tq->tq_nthreads)
+ (void) taskq_thread_spawn(tq);
+
+ spin_unlock_irqrestore(&tq->tq_lock, irqflags);
+ return (rc);
}
-EXPORT_SYMBOL(__taskq_dispatch);
+EXPORT_SYMBOL(taskq_dispatch);
+
+taskqid_t
+taskq_dispatch_delay(taskq_t *tq, task_func_t func, void *arg,
+ uint_t flags, clock_t expire_time)
+{
+ taskqid_t rc = 0;
+ taskq_ent_t *t;
+ unsigned long irqflags;
+
+ ASSERT(tq);
+ ASSERT(func);
+
+ spin_lock_irqsave_nested(&tq->tq_lock, irqflags, tq->tq_lock_class);
+
+ /* Taskq being destroyed and all tasks drained */
+ if (!(tq->tq_flags & TASKQ_ACTIVE))
+ goto out;
+
+ if ((t = task_alloc(tq, flags, &irqflags)) == NULL)
+ goto out;
+
+ spin_lock(&t->tqent_lock);
+
+ /* Queue to the delay list for subsequent execution */
+ list_add_tail(&t->tqent_list, &tq->tq_delay_list);
+
+ t->tqent_id = rc = tq->tq_next_id;
+ tq->tq_next_id++;
+ t->tqent_func = func;
+ t->tqent_arg = arg;
+ t->tqent_taskq = tq;
+ t->tqent_timer.data = (unsigned long)t;
+ t->tqent_timer.function = task_expire;
+ t->tqent_timer.expires = (unsigned long)expire_time;
+ add_timer(&t->tqent_timer);
+
+ ASSERT(!(t->tqent_flags & TQENT_FLAG_PREALLOC));
+
+ spin_unlock(&t->tqent_lock);
+out:
+ /* Spawn additional taskq threads if required. */
+ if (tq->tq_nactive == tq->tq_nthreads)
+ (void) taskq_thread_spawn(tq);
+ spin_unlock_irqrestore(&tq->tq_lock, irqflags);
+ return (rc);
+}
+EXPORT_SYMBOL(taskq_dispatch_delay);
+
+void
+taskq_dispatch_ent(taskq_t *tq, task_func_t func, void *arg, uint_t flags,
+ taskq_ent_t *t)
+{
+ unsigned long irqflags;
+ ASSERT(tq);
+ ASSERT(func);
+
+ spin_lock_irqsave_nested(&tq->tq_lock, irqflags,
+ tq->tq_lock_class);
+
+ /* Taskq being destroyed and all tasks drained */
+ if (!(tq->tq_flags & TASKQ_ACTIVE)) {
+ t->tqent_id = 0;
+ goto out;
+ }
+
+ spin_lock(&t->tqent_lock);
+
+ /*
+ * Mark it as a prealloc'd task. This is important
+ * to ensure that we don't free it later.
+ */
+ t->tqent_flags |= TQENT_FLAG_PREALLOC;
+
+ /* Queue to the priority list instead of the pending list */
+ if (flags & TQ_FRONT)
+ list_add_tail(&t->tqent_list, &tq->tq_prio_list);
+ else
+ list_add_tail(&t->tqent_list, &tq->tq_pend_list);
+
+ t->tqent_id = tq->tq_next_id;
+ tq->tq_next_id++;
+ t->tqent_func = func;
+ t->tqent_arg = arg;
+ t->tqent_taskq = tq;
+
+ spin_unlock(&t->tqent_lock);
+
+ wake_up(&tq->tq_work_waitq);
+out:
+ /* Spawn additional taskq threads if required. */
+ if (tq->tq_nactive == tq->tq_nthreads)
+ (void) taskq_thread_spawn(tq);
+ spin_unlock_irqrestore(&tq->tq_lock, irqflags);
+}
+EXPORT_SYMBOL(taskq_dispatch_ent);
+
+int
+taskq_empty_ent(taskq_ent_t *t)
+{
+ return list_empty(&t->tqent_list);
+}
+EXPORT_SYMBOL(taskq_empty_ent);
+
+void
+taskq_init_ent(taskq_ent_t *t)
+{
+ spin_lock_init(&t->tqent_lock);
+ init_waitqueue_head(&t->tqent_waitq);
+ init_timer(&t->tqent_timer);
+ INIT_LIST_HEAD(&t->tqent_list);
+ t->tqent_id = 0;
+ t->tqent_func = NULL;
+ t->tqent_arg = NULL;
+ t->tqent_flags = 0;
+ t->tqent_taskq = NULL;
+}
+EXPORT_SYMBOL(taskq_init_ent);
/*
- * Returns the lowest incomplete taskqid_t. The taskqid_t may
- * be queued on the pending list or may be on the work list
- * currently being handled, but it is not 100% complete yet.
+ * Return the next pending task, preference is given to tasks on the
+ * priority list which were dispatched with TQ_FRONT.
*/
-static taskqid_t
-taskq_lowest_id(taskq_t *tq)
+static taskq_ent_t *
+taskq_next_ent(taskq_t *tq)
{
- taskqid_t lowest_id = tq->tq_next_id;
- spl_task_t *t;
- ENTRY;
+ struct list_head *list;
- ASSERT(tq);
ASSERT(spin_is_locked(&tq->tq_lock));
- if (!list_empty(&tq->tq_pend_list)) {
- t = list_entry(tq->tq_pend_list.next, spl_task_t, t_list);
- lowest_id = MIN(lowest_id, t->t_id);
- }
+ if (!list_empty(&tq->tq_prio_list))
+ list = &tq->tq_prio_list;
+ else if (!list_empty(&tq->tq_pend_list))
+ list = &tq->tq_pend_list;
+ else
+ return (NULL);
- if (!list_empty(&tq->tq_work_list)) {
- t = list_entry(tq->tq_work_list.next, spl_task_t, t_list);
- lowest_id = MIN(lowest_id, t->t_id);
+ return (list_entry(list->next, taskq_ent_t, tqent_list));
+}
+
+/*
+ * Spawns a new thread for the specified taskq.
+ */
+static void
+taskq_thread_spawn_task(void *arg)
+{
+ taskq_t *tq = (taskq_t *)arg;
+ unsigned long flags;
+
+ (void) taskq_thread_create(tq);
+
+ spin_lock_irqsave_nested(&tq->tq_lock, flags, tq->tq_lock_class);
+ tq->tq_nspawn--;
+ spin_unlock_irqrestore(&tq->tq_lock, flags);
+}
+
+/*
+ * Spawn addition threads for dynamic taskqs (TASKQ_DYNAMIC) the current
+ * number of threads is insufficient to handle the pending tasks. These
+ * new threads must be created by the dedicated dynamic_taskq to avoid
+ * deadlocks between thread creation and memory reclaim. The system_taskq
+ * which is also a dynamic taskq cannot be safely used for this.
+ */
+static int
+taskq_thread_spawn(taskq_t *tq)
+{
+ int spawning = 0;
+
+ if (!(tq->tq_flags & TASKQ_DYNAMIC))
+ return (0);
+
+ if ((tq->tq_nthreads + tq->tq_nspawn < tq->tq_maxthreads) &&
+ (tq->tq_flags & TASKQ_ACTIVE)) {
+ spawning = (++tq->tq_nspawn);
+ taskq_dispatch(dynamic_taskq, taskq_thread_spawn_task,
+ tq, TQ_NOSLEEP);
}
- RETURN(lowest_id);
+ return (spawning);
}
+/*
+ * Threads in a dynamic taskq should only exit once it has been completely
+ * drained and no other threads are actively servicing tasks. This prevents
+ * threads from being created and destroyed more than is required.
+ *
+ * The first thread is the thread list is treated as the primary thread.
+ * There is nothing special about the primary thread but in order to avoid
+ * all the taskq pids from changing we opt to make it long running.
+ */
static int
-taskq_thread(void *args)
+taskq_thread_should_stop(taskq_t *tq, taskq_thread_t *tqt)
{
- DECLARE_WAITQUEUE(wait, current);
- sigset_t blocked;
- taskqid_t id;
- taskq_t *tq = args;
- spl_task_t *t;
- ENTRY;
+ ASSERT(spin_is_locked(&tq->tq_lock));
- ASSERT(tq);
- current->flags |= PF_NOFREEZE;
+ if (!(tq->tq_flags & TASKQ_DYNAMIC))
+ return (0);
- sigfillset(&blocked);
- sigprocmask(SIG_BLOCK, &blocked, NULL);
- flush_signals(current);
+ if (list_first_entry(&(tq->tq_thread_list), taskq_thread_t,
+ tqt_thread_list) == tqt)
+ return (0);
- spin_lock_irqsave(&tq->tq_lock, tq->tq_lock_flags);
- tq->tq_nthreads++;
- wake_up(&tq->tq_wait_waitq);
- set_current_state(TASK_INTERRUPTIBLE);
+ return
+ ((tq->tq_nspawn == 0) && /* No threads are being spawned */
+ (tq->tq_nactive == 0) && /* No threads are handling tasks */
+ (tq->tq_nthreads > 1) && /* More than 1 thread is running */
+ (!taskq_next_ent(tq)) && /* There are no pending tasks */
+ (spl_taskq_thread_dynamic));/* Dynamic taskqs are allowed */
+}
+
+static int
+taskq_thread(void *args)
+{
+ DECLARE_WAITQUEUE(wait, current);
+ sigset_t blocked;
+ taskq_thread_t *tqt = args;
+ taskq_t *tq;
+ taskq_ent_t *t;
+ int seq_tasks = 0;
+ unsigned long flags;
+
+ ASSERT(tqt);
+ ASSERT(tqt->tqt_tq);
+ tq = tqt->tqt_tq;
+ current->flags |= PF_NOFREEZE;
+
+ #if defined(PF_MEMALLOC_NOIO)
+ (void) memalloc_noio_save();
+ #endif
+
+ sigfillset(&blocked);
+ sigprocmask(SIG_BLOCK, &blocked, NULL);
+ flush_signals(current);
+
+ spin_lock_irqsave_nested(&tq->tq_lock, flags, tq->tq_lock_class);
+
+ /* Immediately exit if more threads than allowed were created. */
+ if (tq->tq_nthreads >= tq->tq_maxthreads)
+ goto error;
+
+ tq->tq_nthreads++;
+ list_add_tail(&tqt->tqt_thread_list, &tq->tq_thread_list);
+ wake_up(&tq->tq_wait_waitq);
+ set_current_state(TASK_INTERRUPTIBLE);
+
+ while (!kthread_should_stop()) {
+
+ if (list_empty(&tq->tq_pend_list) &&
+ list_empty(&tq->tq_prio_list)) {
+
+ if (taskq_thread_should_stop(tq, tqt)) {
+ wake_up_all(&tq->tq_wait_waitq);
+ break;
+ }
- while (!kthread_should_stop()) {
+ add_wait_queue_exclusive(&tq->tq_work_waitq, &wait);
+ spin_unlock_irqrestore(&tq->tq_lock, flags);
- add_wait_queue(&tq->tq_work_waitq, &wait);
- if (list_empty(&tq->tq_pend_list)) {
- spin_unlock_irqrestore(&tq->tq_lock, tq->tq_lock_flags);
schedule();
- spin_lock_irqsave(&tq->tq_lock, tq->tq_lock_flags);
+ seq_tasks = 0;
+
+ spin_lock_irqsave_nested(&tq->tq_lock, flags,
+ tq->tq_lock_class);
+ remove_wait_queue(&tq->tq_work_waitq, &wait);
} else {
__set_current_state(TASK_RUNNING);
}
- remove_wait_queue(&tq->tq_work_waitq, &wait);
- if (!list_empty(&tq->tq_pend_list)) {
- t = list_entry(tq->tq_pend_list.next,spl_task_t,t_list);
- list_del_init(&t->t_list);
- list_add_tail(&t->t_list, &tq->tq_work_list);
- tq->tq_nactive++;
- spin_unlock_irqrestore(&tq->tq_lock, tq->tq_lock_flags);
+ if ((t = taskq_next_ent(tq)) != NULL) {
+ list_del_init(&t->tqent_list);
+
+ /* In order to support recursively dispatching a
+ * preallocated taskq_ent_t, tqent_id must be
+ * stored prior to executing tqent_func. */
+ tqt->tqt_id = t->tqent_id;
+ tqt->tqt_task = t;
+
+ /* We must store a copy of the flags prior to
+ * servicing the task (servicing a prealloc'd task
+ * returns the ownership of the tqent back to
+ * the caller of taskq_dispatch). Thus,
+ * tqent_flags _may_ change within the call. */
+ tqt->tqt_flags = t->tqent_flags;
+
+ taskq_insert_in_order(tq, tqt);
+ tq->tq_nactive++;
+ spin_unlock_irqrestore(&tq->tq_lock, flags);
/* Perform the requested task */
- t->t_func(t->t_arg);
+ t->tqent_func(t->tqent_arg);
+
+ spin_lock_irqsave_nested(&tq->tq_lock, flags,
+ tq->tq_lock_class);
+ tq->tq_nactive--;
+ list_del_init(&tqt->tqt_active_list);
+ tqt->tqt_task = NULL;
- spin_lock_irqsave(&tq->tq_lock, tq->tq_lock_flags);
- tq->tq_nactive--;
- id = t->t_id;
- task_done(tq, t);
+ /* For prealloc'd tasks, we don't free anything. */
+ if (!(tqt->tqt_flags & TQENT_FLAG_PREALLOC))
+ task_done(tq, t);
/* When the current lowest outstanding taskqid is
* done calculate the new lowest outstanding id */
- if (tq->tq_lowest_id == id) {
+ if (tq->tq_lowest_id == tqt->tqt_id) {
tq->tq_lowest_id = taskq_lowest_id(tq);
- ASSERT(tq->tq_lowest_id > id);
+ ASSERT3S(tq->tq_lowest_id, >, tqt->tqt_id);
}
- wake_up_all(&tq->tq_wait_waitq);
+ /* Spawn additional taskq threads if required. */
+ if ((++seq_tasks) > spl_taskq_thread_sequential &&
+ taskq_thread_spawn(tq))
+ seq_tasks = 0;
+
+ tqt->tqt_id = 0;
+ tqt->tqt_flags = 0;
+ wake_up_all(&tq->tq_wait_waitq);
+ } else {
+ if (taskq_thread_should_stop(tq, tqt))
+ break;
}
set_current_state(TASK_INTERRUPTIBLE);
- }
+ }
__set_current_state(TASK_RUNNING);
- tq->tq_nthreads--;
- spin_unlock_irqrestore(&tq->tq_lock, tq->tq_lock_flags);
+ tq->tq_nthreads--;
+ list_del_init(&tqt->tqt_thread_list);
+error:
+ kmem_free(tqt, sizeof (taskq_thread_t));
+ spin_unlock_irqrestore(&tq->tq_lock, flags);
- RETURN(0);
+ return (0);
+}
+
+static taskq_thread_t *
+taskq_thread_create(taskq_t *tq)
+{
+ static int last_used_cpu = 0;
+ taskq_thread_t *tqt;
+
+ tqt = kmem_alloc(sizeof (*tqt), KM_PUSHPAGE);
+ INIT_LIST_HEAD(&tqt->tqt_thread_list);
+ INIT_LIST_HEAD(&tqt->tqt_active_list);
+ tqt->tqt_tq = tq;
+ tqt->tqt_id = 0;
+
+ tqt->tqt_thread = spl_kthread_create(taskq_thread, tqt,
+ "%s", tq->tq_name);
+ if (tqt->tqt_thread == NULL) {
+ kmem_free(tqt, sizeof (taskq_thread_t));
+ return (NULL);
+ }
+
+ if (spl_taskq_thread_bind) {
+ last_used_cpu = (last_used_cpu + 1) % num_online_cpus();
+ kthread_bind(tqt->tqt_thread, last_used_cpu);
+ }
+
+ if (spl_taskq_thread_priority)
+ set_user_nice(tqt->tqt_thread, PRIO_TO_NICE(tq->tq_pri));
+
+ wake_up_process(tqt->tqt_thread);
+
+ return (tqt);
}
taskq_t *
-__taskq_create(const char *name, int nthreads, pri_t pri,
- int minalloc, int maxalloc, uint_t flags)
+taskq_create(const char *name, int nthreads, pri_t pri,
+ int minalloc, int maxalloc, uint_t flags)
{
- taskq_t *tq;
- struct task_struct *t;
- int rc = 0, i, j = 0;
- ENTRY;
+ taskq_t *tq;
+ taskq_thread_t *tqt;
+ int count = 0, rc = 0, i;
+ unsigned long irqflags;
- ASSERT(name != NULL);
- ASSERT(pri <= maxclsyspri);
- ASSERT(minalloc >= 0);
- ASSERT(maxalloc <= INT_MAX);
- ASSERT(!(flags & (TASKQ_CPR_SAFE | TASKQ_DYNAMIC))); /* Unsupported */
+ ASSERT(name != NULL);
+ ASSERT(minalloc >= 0);
+ ASSERT(maxalloc <= INT_MAX);
+ ASSERT(!(flags & (TASKQ_CPR_SAFE))); /* Unsupported */
/* Scale the number of threads using nthreads as a percentage */
if (flags & TASKQ_THREADS_CPU_PCT) {
nthreads = MAX((num_online_cpus() * nthreads) / 100, 1);
}
- tq = kmem_alloc(sizeof(*tq), KM_SLEEP);
- if (tq == NULL)
- RETURN(NULL);
-
- tq->tq_threads = kmem_alloc(nthreads * sizeof(t), KM_SLEEP);
- if (tq->tq_threads == NULL) {
- kmem_free(tq, sizeof(*tq));
- RETURN(NULL);
- }
-
- spin_lock_init(&tq->tq_lock);
- spin_lock_irqsave(&tq->tq_lock, tq->tq_lock_flags);
- tq->tq_name = name;
- tq->tq_nactive = 0;
- tq->tq_nthreads = 0;
- tq->tq_pri = pri;
- tq->tq_minalloc = minalloc;
- tq->tq_maxalloc = maxalloc;
- tq->tq_nalloc = 0;
- tq->tq_flags = (flags | TQ_ACTIVE);
- tq->tq_next_id = 1;
- tq->tq_lowest_id = 1;
- INIT_LIST_HEAD(&tq->tq_free_list);
- INIT_LIST_HEAD(&tq->tq_work_list);
- INIT_LIST_HEAD(&tq->tq_pend_list);
- init_waitqueue_head(&tq->tq_work_waitq);
- init_waitqueue_head(&tq->tq_wait_waitq);
-
- if (flags & TASKQ_PREPOPULATE)
- for (i = 0; i < minalloc; i++)
- task_done(tq, task_alloc(tq, TQ_SLEEP | TQ_NEW));
-
- spin_unlock_irqrestore(&tq->tq_lock, tq->tq_lock_flags);
-
- for (i = 0; i < nthreads; i++) {
- t = kthread_create(taskq_thread, tq, "%s/%d", name, i);
- if (t) {
- tq->tq_threads[i] = t;
- kthread_bind(t, i % num_online_cpus());
- set_user_nice(t, PRIO_TO_NICE(pri));
- wake_up_process(t);
- j++;
- } else {
- tq->tq_threads[i] = NULL;
- rc = 1;
- }
- }
-
- /* Wait for all threads to be started before potential destroy */
- wait_event(tq->tq_wait_waitq, tq->tq_nthreads == j);
-
- if (rc) {
- __taskq_destroy(tq);
- tq = NULL;
- }
-
- RETURN(tq);
-}
-EXPORT_SYMBOL(__taskq_create);
+ tq = kmem_alloc(sizeof (*tq), KM_PUSHPAGE);
+ if (tq == NULL)
+ return (NULL);
+
+ spin_lock_init(&tq->tq_lock);
+ INIT_LIST_HEAD(&tq->tq_thread_list);
+ INIT_LIST_HEAD(&tq->tq_active_list);
+ tq->tq_name = strdup(name);
+ tq->tq_nactive = 0;
+ tq->tq_nthreads = 0;
+ tq->tq_nspawn = 0;
+ tq->tq_maxthreads = nthreads;
+ tq->tq_pri = pri;
+ tq->tq_minalloc = minalloc;
+ tq->tq_maxalloc = maxalloc;
+ tq->tq_nalloc = 0;
+ tq->tq_flags = (flags | TASKQ_ACTIVE);
+ tq->tq_next_id = 1;
+ tq->tq_lowest_id = 1;
+ INIT_LIST_HEAD(&tq->tq_free_list);
+ INIT_LIST_HEAD(&tq->tq_pend_list);
+ INIT_LIST_HEAD(&tq->tq_prio_list);
+ INIT_LIST_HEAD(&tq->tq_delay_list);
+ init_waitqueue_head(&tq->tq_work_waitq);
+ init_waitqueue_head(&tq->tq_wait_waitq);
+ tq->tq_lock_class = TQ_LOCK_GENERAL;
+
+ if (flags & TASKQ_PREPOPULATE) {
+ spin_lock_irqsave_nested(&tq->tq_lock, irqflags,
+ tq->tq_lock_class);
+
+ for (i = 0; i < minalloc; i++)
+ task_done(tq, task_alloc(tq, TQ_PUSHPAGE | TQ_NEW,
+ &irqflags));
+
+ spin_unlock_irqrestore(&tq->tq_lock, irqflags);
+ }
+
+ if ((flags & TASKQ_DYNAMIC) && spl_taskq_thread_dynamic)
+ nthreads = 1;
+
+ for (i = 0; i < nthreads; i++) {
+ tqt = taskq_thread_create(tq);
+ if (tqt == NULL)
+ rc = 1;
+ else
+ count++;
+ }
+
+ /* Wait for all threads to be started before potential destroy */
+ wait_event(tq->tq_wait_waitq, tq->tq_nthreads == count);
+
+ if (rc) {
+ taskq_destroy(tq);
+ tq = NULL;
+ }
+
+ return (tq);
+}
+EXPORT_SYMBOL(taskq_create);
void
-__taskq_destroy(taskq_t *tq)
+taskq_destroy(taskq_t *tq)
{
- spl_task_t *t;
- int i, nthreads;
- ENTRY;
+ struct task_struct *thread;
+ taskq_thread_t *tqt;
+ taskq_ent_t *t;
+ unsigned long flags;
ASSERT(tq);
- spin_lock_irqsave(&tq->tq_lock, tq->tq_lock_flags);
- tq->tq_flags &= ~TQ_ACTIVE;
- spin_unlock_irqrestore(&tq->tq_lock, tq->tq_lock_flags);
-
- /* TQ_ACTIVE cleared prevents new tasks being added to pending */
- __taskq_wait(tq);
+ spin_lock_irqsave_nested(&tq->tq_lock, flags, tq->tq_lock_class);
+ tq->tq_flags &= ~TASKQ_ACTIVE;
+ spin_unlock_irqrestore(&tq->tq_lock, flags);
+
+ /*
+ * When TASKQ_ACTIVE is clear new tasks may not be added nor may
+ * new worker threads be spawned for dynamic taskq.
+ */
+ if (dynamic_taskq != NULL)
+ taskq_wait_outstanding(dynamic_taskq, 0);
+
+ taskq_wait(tq);
+
+ spin_lock_irqsave_nested(&tq->tq_lock, flags, tq->tq_lock_class);
+
+ /*
+ * Signal each thread to exit and block until it does. Each thread
+ * is responsible for removing itself from the list and freeing its
+ * taskq_thread_t. This allows for idle threads to opt to remove
+ * themselves from the taskq. They can be recreated as needed.
+ */
+ while (!list_empty(&tq->tq_thread_list)) {
+ tqt = list_entry(tq->tq_thread_list.next,
+ taskq_thread_t, tqt_thread_list);
+ thread = tqt->tqt_thread;
+ spin_unlock_irqrestore(&tq->tq_lock, flags);
+
+ kthread_stop(thread);
+
+ spin_lock_irqsave_nested(&tq->tq_lock, flags,
+ tq->tq_lock_class);
+ }
- nthreads = tq->tq_nthreads;
- for (i = 0; i < nthreads; i++)
- if (tq->tq_threads[i])
- kthread_stop(tq->tq_threads[i]);
+ while (!list_empty(&tq->tq_free_list)) {
+ t = list_entry(tq->tq_free_list.next, taskq_ent_t, tqent_list);
- spin_lock_irqsave(&tq->tq_lock, tq->tq_lock_flags);
+ ASSERT(!(t->tqent_flags & TQENT_FLAG_PREALLOC));
- while (!list_empty(&tq->tq_free_list)) {
- t = list_entry(tq->tq_free_list.next, spl_task_t, t_list);
- list_del_init(&t->t_list);
- task_free(tq, t);
- }
+ list_del_init(&t->tqent_list);
+ task_free(tq, t);
+ }
- ASSERT(tq->tq_nthreads == 0);
- ASSERT(tq->tq_nalloc == 0);
- ASSERT(list_empty(&tq->tq_free_list));
- ASSERT(list_empty(&tq->tq_work_list));
- ASSERT(list_empty(&tq->tq_pend_list));
+ ASSERT0(tq->tq_nthreads);
+ ASSERT0(tq->tq_nalloc);
+ ASSERT0(tq->tq_nspawn);
+ ASSERT(list_empty(&tq->tq_thread_list));
+ ASSERT(list_empty(&tq->tq_active_list));
+ ASSERT(list_empty(&tq->tq_free_list));
+ ASSERT(list_empty(&tq->tq_pend_list));
+ ASSERT(list_empty(&tq->tq_prio_list));
+ ASSERT(list_empty(&tq->tq_delay_list));
- spin_unlock_irqrestore(&tq->tq_lock, tq->tq_lock_flags);
- kmem_free(tq->tq_threads, nthreads * sizeof(spl_task_t *));
- kmem_free(tq, sizeof(taskq_t));
+ spin_unlock_irqrestore(&tq->tq_lock, flags);
- EXIT;
+ strfree(tq->tq_name);
+ kmem_free(tq, sizeof (taskq_t));
}
-EXPORT_SYMBOL(__taskq_destroy);
+EXPORT_SYMBOL(taskq_destroy);
int
spl_taskq_init(void)
{
- ENTRY;
-
- /* Solaris creates a dynamic taskq of up to 64 threads, however in
- * a Linux environment 1 thread per-core is usually about right */
- system_taskq = taskq_create("spl_system_taskq", num_online_cpus(),
- minclsyspri, 4, 512, TASKQ_PREPOPULATE);
+ system_taskq = taskq_create("spl_system_taskq", MAX(boot_ncpus, 64),
+ maxclsyspri, boot_ncpus, INT_MAX, TASKQ_PREPOPULATE|TASKQ_DYNAMIC);
if (system_taskq == NULL)
- RETURN(1);
+ return (1);
- RETURN(0);
+ dynamic_taskq = taskq_create("spl_dynamic_taskq", 1,
+ maxclsyspri, boot_ncpus, INT_MAX, TASKQ_PREPOPULATE);
+ if (dynamic_taskq == NULL) {
+ taskq_destroy(system_taskq);
+ return (1);
+ }
+
+ /* This is used to annotate tq_lock, so
+ * taskq_dispatch -> taskq_thread_spawn -> taskq_dispatch
+ * does not trigger a lockdep warning re: possible recursive locking
+ */
+ dynamic_taskq->tq_lock_class = TQ_LOCK_DYNAMIC;
+
+ return (0);
}
void
spl_taskq_fini(void)
{
- ENTRY;
+ taskq_destroy(dynamic_taskq);
+ dynamic_taskq = NULL;
+
taskq_destroy(system_taskq);
- EXIT;
+ system_taskq = NULL;
}
projects / mirror_spl.git / blobdiff