freebsd-nq/lib/libzpool/taskq.c
Brian Behlendorf 1e33ac1e26 Fix Solaris thread dependency by using pthreads
This is a portability change which removes the dependence of the Solaris
thread library.  All locations where Solaris thread API was used before
have been replaced with equivilant Solaris kernel style thread calls.
In user space the kernel style threading API is implemented in term of
the portable pthreads library.  This includes all threads, mutexs,
condition variables, reader/writer locks, and taskqs.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2010-08-31 08:38:47 -07:00

300 lines
6.8 KiB
C

/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2010 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#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 {
kmutex_t tq_lock;
krwlock_t tq_threadlock;
kcondvar_t tq_dispatch_cv;
kcondvar_t tq_wait_cv;
kthread_t **tq_threadlist;
int tq_flags;
int tq_active;
int tq_nthreads;
int tq_nalloc;
int tq_minalloc;
int tq_maxalloc;
kcondvar_t tq_maxalloc_cv;
int tq_maxalloc_wait;
task_t *tq_freelist;
task_t tq_task;
};
static task_t *
task_alloc(taskq_t *tq, int tqflags)
{
task_t *t;
int rv;
again: if ((t = tq->tq_freelist) != NULL && tq->tq_nalloc >= tq->tq_minalloc) {
tq->tq_freelist = t->task_next;
} else {
if (tq->tq_nalloc >= tq->tq_maxalloc) {
if (!(tqflags & KM_SLEEP))
return (NULL);
/*
* We don't want to exceed tq_maxalloc, but we can't
* wait for other tasks to complete (and thus free up
* task structures) without risking deadlock with
* the caller. So, we just delay for one second
* to throttle the allocation rate. If we have tasks
* complete before one second timeout expires then
* taskq_ent_free will signal us and we will
* immediately retry the allocation.
*/
tq->tq_maxalloc_wait++;
rv = cv_timedwait(&tq->tq_maxalloc_cv,
&tq->tq_lock, ddi_get_lbolt() + hz);
tq->tq_maxalloc_wait--;
if (rv > 0)
goto again; /* signaled */
}
mutex_exit(&tq->tq_lock);
t = kmem_alloc(sizeof (task_t), tqflags);
mutex_enter(&tq->tq_lock);
if (t != NULL)
tq->tq_nalloc++;
}
return (t);
}
static void
task_free(taskq_t *tq, task_t *t)
{
if (tq->tq_nalloc <= tq->tq_minalloc) {
t->task_next = tq->tq_freelist;
tq->tq_freelist = t;
} else {
tq->tq_nalloc--;
mutex_exit(&tq->tq_lock);
kmem_free(t, sizeof (task_t));
mutex_enter(&tq->tq_lock);
}
if (tq->tq_maxalloc_wait)
cv_signal(&tq->tq_maxalloc_cv);
}
taskqid_t
taskq_dispatch(taskq_t *tq, task_func_t func, void *arg, uint_t tqflags)
{
task_t *t;
if (taskq_now) {
func(arg);
return (1);
}
mutex_enter(&tq->tq_lock);
ASSERT(tq->tq_flags & TASKQ_ACTIVE);
if ((t = task_alloc(tq, tqflags)) == NULL) {
mutex_exit(&tq->tq_lock);
return (0);
}
if (tqflags & TQ_FRONT) {
t->task_next = tq->tq_task.task_next;
t->task_prev = &tq->tq_task;
} else {
t->task_next = &tq->tq_task;
t->task_prev = tq->tq_task.task_prev;
}
t->task_next->task_prev = t;
t->task_prev->task_next = t;
t->task_func = func;
t->task_arg = arg;
cv_signal(&tq->tq_dispatch_cv);
mutex_exit(&tq->tq_lock);
return (1);
}
void
taskq_wait(taskq_t *tq)
{
mutex_enter(&tq->tq_lock);
while (tq->tq_task.task_next != &tq->tq_task || tq->tq_active != 0)
cv_wait(&tq->tq_wait_cv, &tq->tq_lock);
mutex_exit(&tq->tq_lock);
}
static void
taskq_thread(void *arg)
{
taskq_t *tq = arg;
task_t *t;
mutex_enter(&tq->tq_lock);
while (tq->tq_flags & TASKQ_ACTIVE) {
if ((t = tq->tq_task.task_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;
mutex_exit(&tq->tq_lock);
rw_enter(&tq->tq_threadlock, RW_READER);
t->task_func(t->task_arg);
rw_exit(&tq->tq_threadlock);
mutex_enter(&tq->tq_lock);
task_free(tq, t);
}
tq->tq_nthreads--;
cv_broadcast(&tq->tq_wait_cv);
mutex_exit(&tq->tq_lock);
thread_exit();
}
/*ARGSUSED*/
taskq_t *
taskq_create(const char *name, int nthreads, pri_t pri,
int minalloc, int maxalloc, uint_t flags)
{
taskq_t *tq = kmem_zalloc(sizeof (taskq_t), KM_SLEEP);
int t;
if (flags & TASKQ_THREADS_CPU_PCT) {
int pct;
ASSERT3S(nthreads, >=, 0);
ASSERT3S(nthreads, <=, 100);
pct = MIN(nthreads, 100);
pct = MAX(pct, 0);
nthreads = (sysconf(_SC_NPROCESSORS_ONLN) * pct) / 100;
nthreads = MAX(nthreads, 1); /* need at least 1 thread */
} else {
ASSERT3S(nthreads, >=, 1);
}
rw_init(&tq->tq_threadlock, NULL, RW_DEFAULT, NULL);
mutex_init(&tq->tq_lock, NULL, MUTEX_DEFAULT, NULL);
cv_init(&tq->tq_dispatch_cv, NULL, CV_DEFAULT, NULL);
cv_init(&tq->tq_wait_cv, NULL, CV_DEFAULT, NULL);
cv_init(&tq->tq_maxalloc_cv, NULL, CV_DEFAULT, NULL);
tq->tq_flags = flags | TASKQ_ACTIVE;
tq->tq_active = nthreads;
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_threadlist = kmem_alloc(nthreads*sizeof(kthread_t *), KM_SLEEP);
if (flags & TASKQ_PREPOPULATE) {
mutex_enter(&tq->tq_lock);
while (minalloc-- > 0)
task_free(tq, task_alloc(tq, KM_SLEEP));
mutex_exit(&tq->tq_lock);
}
for (t = 0; t < nthreads; t++)
VERIFY((tq->tq_threadlist[t] = thread_create(NULL, 0,
taskq_thread, tq, TS_RUN, NULL, 0, 0)) != NULL);
return (tq);
}
void
taskq_destroy(taskq_t *tq)
{
int nthreads = tq->tq_nthreads;
taskq_wait(tq);
mutex_enter(&tq->tq_lock);
tq->tq_flags &= ~TASKQ_ACTIVE;
cv_broadcast(&tq->tq_dispatch_cv);
while (tq->tq_nthreads != 0)
cv_wait(&tq->tq_wait_cv, &tq->tq_lock);
tq->tq_minalloc = 0;
while (tq->tq_nalloc != 0) {
ASSERT(tq->tq_freelist != NULL);
task_free(tq, task_alloc(tq, KM_SLEEP));
}
mutex_exit(&tq->tq_lock);
kmem_free(tq->tq_threadlist, nthreads * sizeof (kthread_t *));
rw_destroy(&tq->tq_threadlock);
mutex_destroy(&tq->tq_lock);
cv_destroy(&tq->tq_dispatch_cv);
cv_destroy(&tq->tq_wait_cv);
cv_destroy(&tq->tq_maxalloc_cv);
kmem_free(tq, sizeof (taskq_t));
}
int
taskq_member(taskq_t *tq, kthread_t *t)
{
int i;
if (taskq_now)
return (1);
for (i = 0; i < tq->tq_nthreads; i++)
if (tq->tq_threadlist[i] == t)
return (1);
return (0);
}
void
system_taskq_init(void)
{
system_taskq = taskq_create("system_taskq", 64, minclsyspri, 4, 512,
TASKQ_DYNAMIC | TASKQ_PREPOPULATE);
}
void
system_taskq_fini(void)
{
taskq_destroy(system_taskq);
system_taskq = NULL; /* defensive */
}