Revert "Create a new thread during recursive taskq dispatch if necessary"

This reverts commit 076821e due to a locking issue uncovered in
subsequent testing.  An ASSERT is hit due to tq->tq_nspawn being
updated outside the lock.  The patch will need to be reworked.

VERIFY3(0 == tq->tq_nspawn) failed (0 == -1)

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #472
This commit is contained in:
Brian Behlendorf 2015-08-31 17:00:17 -07:00
parent 076821eaff
commit 801b56090b

View File

@ -53,7 +53,6 @@ EXPORT_SYMBOL(system_taskq);
/* 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 taskq_thread_spawn(taskq_t *tq, int seq_tasks);
static int
task_km_flags(uint_t flags)
@ -534,7 +533,6 @@ taskq_dispatch(taskq_t *tq, task_func_t func, void *arg, uint_t flags)
{
taskq_ent_t *t;
taskqid_t rc = 0;
boolean_t threadlimit = B_FALSE;
ASSERT(tq);
ASSERT(func);
@ -576,13 +574,7 @@ taskq_dispatch(taskq_t *tq, task_func_t func, void *arg, uint_t flags)
wake_up(&tq->tq_work_waitq);
out:
threadlimit = (tq->tq_nactive == tq->tq_nthreads);
spin_unlock_irqrestore(&tq->tq_lock, tq->tq_lock_flags);
/* Spawn additional taskq threads if required. */
if (threadlimit && taskq_member(tq, current))
(void) taskq_thread_spawn(tq, spl_taskq_thread_sequential + 1);
return (rc);
}
EXPORT_SYMBOL(taskq_dispatch);
@ -593,7 +585,6 @@ taskq_dispatch_delay(taskq_t *tq, task_func_t func, void *arg,
{
taskqid_t rc = 0;
taskq_ent_t *t;
boolean_t threadlimit = B_FALSE;
ASSERT(tq);
ASSERT(func);
@ -626,13 +617,7 @@ taskq_dispatch_delay(taskq_t *tq, task_func_t func, void *arg,
spin_unlock(&t->tqent_lock);
out:
threadlimit = (tq->tq_nactive == tq->tq_nthreads);
spin_unlock_irqrestore(&tq->tq_lock, tq->tq_lock_flags);
/* Spawn additional taskq threads if required. */
if (threadlimit && taskq_member(tq, current))
(void) taskq_thread_spawn(tq, spl_taskq_thread_sequential + 1);
return (rc);
}
EXPORT_SYMBOL(taskq_dispatch_delay);
@ -641,8 +626,6 @@ void
taskq_dispatch_ent(taskq_t *tq, task_func_t func, void *arg, uint_t flags,
taskq_ent_t *t)
{
boolean_t threadlimit = B_FALSE;
ASSERT(tq);
ASSERT(func);
@ -678,12 +661,7 @@ taskq_dispatch_ent(taskq_t *tq, task_func_t func, void *arg, uint_t flags,
wake_up(&tq->tq_work_waitq);
out:
threadlimit = (tq->tq_nactive == tq->tq_nthreads);
spin_unlock_irqrestore(&tq->tq_lock, tq->tq_lock_flags);
/* Spawn additional taskq threads if required. */
if (threadlimit && taskq_member(tq, current))
(void) taskq_thread_spawn(tq, spl_taskq_thread_sequential + 1);
}
EXPORT_SYMBOL(taskq_dispatch_ent);