Use taskq for dump_bytes()
[zfs.git] / lib / libzpool / taskq.c
index 36c0ec7..96c0d5c 100644 (file)
  * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
+/*
+ * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
+ * Copyright 2012 Garrett D'Amore <garrett@damore.org>.  All rights reserved.
+ */
 
 #include <sys/zfs_context.h>
 
 int taskq_now;
 taskq_t *system_taskq;
 
-typedef struct task {
-       struct task     *task_next;
-       struct task     *task_prev;
-       task_func_t     *task_func;
-       void            *task_arg;
-} task_t;
-
 #define        TASKQ_ACTIVE    0x00010000
 
 struct taskq {
@@ -51,18 +48,19 @@ struct taskq {
        int             tq_maxalloc;
        kcondvar_t      tq_maxalloc_cv;
        int             tq_maxalloc_wait;
-       task_t          *tq_freelist;
-       task_t          tq_task;
+       taskq_ent_t     *tq_freelist;
+       taskq_ent_t     tq_task;
 };
 
-static task_t *
+static taskq_ent_t *
 task_alloc(taskq_t *tq, int tqflags)
 {
-       task_t *t;
+       taskq_ent_t *t;
        int rv;
 
 again: if ((t = tq->tq_freelist) != NULL && tq->tq_nalloc >= tq->tq_minalloc) {
-               tq->tq_freelist = t->task_next;
+               ASSERT(!(t->tqent_flags & TQENT_FLAG_PREALLOC));
+               tq->tq_freelist = t->tqent_next;
        } else {
                if (tq->tq_nalloc >= tq->tq_maxalloc) {
                        if (!(tqflags & KM_SLEEP))
@@ -87,25 +85,28 @@ again:      if ((t = tq->tq_freelist) != NULL && tq->tq_nalloc >= tq->tq_minalloc) {
                }
                mutex_exit(&tq->tq_lock);
 
-               t = kmem_alloc(sizeof (task_t), tqflags);
+               t = kmem_alloc(sizeof (taskq_ent_t), tqflags);
 
                mutex_enter(&tq->tq_lock);
-               if (t != NULL)
+               if (t != NULL) {
+                       /* Make sure we start without any flags */
+                       t->tqent_flags = 0;
                        tq->tq_nalloc++;
+               }
        }
        return (t);
 }
 
 static void
-task_free(taskq_t *tq, task_t *t)
+task_free(taskq_t *tq, taskq_ent_t *t)
 {
        if (tq->tq_nalloc <= tq->tq_minalloc) {
-               t->task_next = tq->tq_freelist;
+               t->tqent_next = tq->tq_freelist;
                tq->tq_freelist = t;
        } else {
                tq->tq_nalloc--;
                mutex_exit(&tq->tq_lock);
-               kmem_free(t, sizeof (task_t));
+               kmem_free(t, sizeof (taskq_ent_t));
                mutex_enter(&tq->tq_lock);
        }
 
@@ -116,7 +117,7 @@ task_free(taskq_t *tq, task_t *t)
 taskqid_t
 taskq_dispatch(taskq_t *tq, task_func_t func, void *arg, uint_t tqflags)
 {
-       task_t *t;
+       taskq_ent_t *t;
 
        if (taskq_now) {
                func(arg);
@@ -130,55 +131,122 @@ taskq_dispatch(taskq_t *tq, task_func_t func, void *arg, uint_t tqflags)
                return (0);
        }
        if (tqflags & TQ_FRONT) {
-               t->task_next = tq->tq_task.task_next;
-               t->task_prev = &tq->tq_task;
+               t->tqent_next = tq->tq_task.tqent_next;
+               t->tqent_prev = &tq->tq_task;
        } else {
-               t->task_next = &tq->tq_task;
-               t->task_prev = tq->tq_task.task_prev;
+               t->tqent_next = &tq->tq_task;
+               t->tqent_prev = tq->tq_task.tqent_prev;
        }
-       t->task_next->task_prev = t;
-       t->task_prev->task_next = t;
-       t->task_func = func;
-       t->task_arg = arg;
+       t->tqent_next->tqent_prev = t;
+       t->tqent_prev->tqent_next = t;
+       t->tqent_func = func;
+       t->tqent_arg = arg;
+       t->tqent_flags = 0;
        cv_signal(&tq->tq_dispatch_cv);
        mutex_exit(&tq->tq_lock);
        return (1);
 }
 
+taskqid_t
+taskq_dispatch_delay(taskq_t *tq,  task_func_t func, void *arg, uint_t tqflags,
+    clock_t expire_time)
+{
+       return (0);
+}
+
+int
+taskq_empty_ent(taskq_ent_t *t)
+{
+       return t->tqent_next == NULL;
+}
+
+void
+taskq_init_ent(taskq_ent_t *t)
+{
+       t->tqent_next = NULL;
+       t->tqent_prev = NULL;
+       t->tqent_func = NULL;
+       t->tqent_arg = NULL;
+       t->tqent_flags = 0;
+}
+
+void
+taskq_dispatch_ent(taskq_t *tq, task_func_t func, void *arg, uint_t flags,
+    taskq_ent_t *t)
+{
+       ASSERT(func != NULL);
+       ASSERT(!(tq->tq_flags & TASKQ_DYNAMIC));
+
+       /*
+        * 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;
+       /*
+        * Enqueue the task to the underlying queue.
+        */
+       mutex_enter(&tq->tq_lock);
+
+       if (flags & TQ_FRONT) {
+               t->tqent_next = tq->tq_task.tqent_next;
+               t->tqent_prev = &tq->tq_task;
+       } else {
+               t->tqent_next = &tq->tq_task;
+               t->tqent_prev = tq->tq_task.tqent_prev;
+       }
+       t->tqent_next->tqent_prev = t;
+       t->tqent_prev->tqent_next = t;
+       t->tqent_func = func;
+       t->tqent_arg = arg;
+       cv_signal(&tq->tq_dispatch_cv);
+       mutex_exit(&tq->tq_lock);
+}
+
 void
 taskq_wait(taskq_t *tq)
 {
        mutex_enter(&tq->tq_lock);
-       while (tq->tq_task.task_next != &tq->tq_task || tq->tq_active != 0)
+       while (tq->tq_task.tqent_next != &tq->tq_task || tq->tq_active != 0)
                cv_wait(&tq->tq_wait_cv, &tq->tq_lock);
        mutex_exit(&tq->tq_lock);
 }
 
+void
+taskq_wait_id(taskq_t *tq, taskqid_t id)
+{
+       taskq_wait(tq);
+}
+
 static void
 taskq_thread(void *arg)
 {
        taskq_t *tq = arg;
-       task_t *t;
+       taskq_ent_t *t;
+       boolean_t prealloc;
 
        mutex_enter(&tq->tq_lock);
        while (tq->tq_flags & TASKQ_ACTIVE) {
-               if ((t = tq->tq_task.task_next) == &tq->tq_task) {
+               if ((t = tq->tq_task.tqent_next) == &tq->tq_task) {
                        if (--tq->tq_active == 0)
                                cv_broadcast(&tq->tq_wait_cv);
                        cv_wait(&tq->tq_dispatch_cv, &tq->tq_lock);
                        tq->tq_active++;
                        continue;
                }
-               t->task_prev->task_next = t->task_next;
-               t->task_next->task_prev = t->task_prev;
+               t->tqent_prev->tqent_next = t->tqent_next;
+               t->tqent_next->tqent_prev = t->tqent_prev;
+               t->tqent_next = NULL;
+               t->tqent_prev = NULL;
+               prealloc = t->tqent_flags & TQENT_FLAG_PREALLOC;
                mutex_exit(&tq->tq_lock);
 
                rw_enter(&tq->tq_threadlock, RW_READER);
-               t->task_func(t->task_arg);
+               t->tqent_func(t->tqent_arg);
                rw_exit(&tq->tq_threadlock);
 
                mutex_enter(&tq->tq_lock);
-               task_free(tq, t);
+               if (!prealloc)
+                       task_free(tq, t);
        }
        tq->tq_nthreads--;
        cv_broadcast(&tq->tq_wait_cv);
@@ -217,8 +285,8 @@ taskq_create(const char *name, int nthreads, pri_t pri,
        tq->tq_nthreads = nthreads;
        tq->tq_minalloc = minalloc;
        tq->tq_maxalloc = maxalloc;
-       tq->tq_task.task_next = &tq->tq_task;
-       tq->tq_task.task_prev = &tq->tq_task;
+       tq->tq_task.tqent_next = &tq->tq_task;
+       tq->tq_task.tqent_prev = &tq->tq_task;
        tq->tq_threadlist = kmem_alloc(nthreads*sizeof(kthread_t *), KM_SLEEP);
 
        if (flags & TASKQ_PREPOPULATE) {
@@ -284,6 +352,12 @@ taskq_member(taskq_t *tq, kthread_t *t)
        return (0);
 }
 
+int
+taskq_cancel_id(taskq_t *tq, taskqid_t id)
+{
+       return (ENOENT);
+}
+
 void
 system_taskq_init(void)
 {