Module Name: src
Committed By: ozaki-r
Date: Thu Dec 28 07:00:52 UTC 2017
Modified Files:
src/share/man/man9: workqueue.9
src/sys/kern: subr_workqueue.c
src/sys/sys: workqueue.h
Log Message:
Add workqueue_wait that waits for a specific work to finish
The caller must ensure that no new work is enqueued before calling
workqueue_wait. Note that Note that if the workqueue is WQ_PERCPU, the caller
can enqueue a new work to another queue other than the waiting queue.
Discussed on tech-kern@
To generate a diff of this commit:
cvs rdiff -u -r1.11 -r1.12 src/share/man/man9/workqueue.9
cvs rdiff -u -r1.33 -r1.34 src/sys/kern/subr_workqueue.c
cvs rdiff -u -r1.9 -r1.10 src/sys/sys/workqueue.h
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/share/man/man9/workqueue.9
diff -u src/share/man/man9/workqueue.9:1.11 src/share/man/man9/workqueue.9:1.12
--- src/share/man/man9/workqueue.9:1.11 Tue Oct 13 04:22:24 2015
+++ src/share/man/man9/workqueue.9 Thu Dec 28 07:00:52 2017
@@ -1,4 +1,4 @@
-.\" $NetBSD: workqueue.9,v 1.11 2015/10/13 04:22:24 riastradh Exp $
+.\" $NetBSD: workqueue.9,v 1.12 2017/12/28 07:00:52 ozaki-r Exp $
.\"
.\" Copyright (c)2005 YAMAMOTO Takashi,
.\" All rights reserved.
@@ -25,7 +25,7 @@
.\" SUCH DAMAGE.
.\"
.\" ------------------------------------------------------------
-.Dd October 24, 2011
+.Dd December 28, 2017
.Dt WORKQUEUE 9
.Os
.\" ------------------------------------------------------------
@@ -47,6 +47,10 @@
"struct workqueue *wq" "struct work *wk" "struct cpu_info *ci"
.\" - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
.Ft void
+.Fn workqueue_wait \
+"struct workqueue *wq" "struct work *wk"
+.\" - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+.Ft void
.Fn workqueue_destroy \
"struct workqueue *wq"
.\" ------------------------------------------------------------
@@ -118,6 +122,19 @@ the
framework.
.Pp
.\" - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+.Fn workqueue_wait
+waits for a specified work
+.Fa wk
+on the workqueue
+.Fa wq
+to finish.
+The caller must ensure that no new work will be enqueued to the workqueue
+beforehand.
+Note that if the workqueue is
+.Dv WQ_PERCPU ,
+the caller can enqueue a new work to another queue other than the waiting queue.
+.Pp
+.\" - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
.Fn workqueue_destroy
destroys a workqueue and frees associated resources.
The caller should ensure that the workqueue has no work enqueued beforehand.
Index: src/sys/kern/subr_workqueue.c
diff -u src/sys/kern/subr_workqueue.c:1.33 src/sys/kern/subr_workqueue.c:1.34
--- src/sys/kern/subr_workqueue.c:1.33 Sun Oct 7 22:16:21 2012
+++ src/sys/kern/subr_workqueue.c Thu Dec 28 07:00:52 2017
@@ -1,4 +1,4 @@
-/* $NetBSD: subr_workqueue.c,v 1.33 2012/10/07 22:16:21 matt Exp $ */
+/* $NetBSD: subr_workqueue.c,v 1.34 2017/12/28 07:00:52 ozaki-r Exp $ */
/*-
* Copyright (c)2002, 2005, 2006, 2007 YAMAMOTO Takashi,
@@ -27,7 +27,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: subr_workqueue.c,v 1.33 2012/10/07 22:16:21 matt Exp $");
+__KERNEL_RCSID(0, "$NetBSD: subr_workqueue.c,v 1.34 2017/12/28 07:00:52 ozaki-r Exp $");
#include <sys/param.h>
#include <sys/cpu.h>
@@ -49,8 +49,10 @@ SIMPLEQ_HEAD(workqhead, work_impl);
struct workqueue_queue {
kmutex_t q_mutex;
kcondvar_t q_cv;
- struct workqhead q_queue;
+ struct workqhead q_queue_pending;
+ struct workqhead q_queue_running;
lwp_t *q_worker;
+ work_impl_t *q_waiter;
};
struct workqueue {
@@ -115,24 +117,29 @@ workqueue_worker(void *cookie)
q = workqueue_queue_lookup(wq, curlwp->l_cpu);
for (;;) {
- struct workqhead tmp;
-
/*
* we violate abstraction of SIMPLEQ.
*/
-#if defined(DIAGNOSTIC)
- tmp.sqh_last = (void *)POISON;
-#endif /* defined(DIAGNOSTIC) */
-
mutex_enter(&q->q_mutex);
- while (SIMPLEQ_EMPTY(&q->q_queue))
+ while (SIMPLEQ_EMPTY(&q->q_queue_pending))
cv_wait(&q->q_cv, &q->q_mutex);
- tmp.sqh_first = q->q_queue.sqh_first; /* XXX */
- SIMPLEQ_INIT(&q->q_queue);
+ KASSERT(SIMPLEQ_EMPTY(&q->q_queue_running));
+ q->q_queue_running.sqh_first =
+ q->q_queue_pending.sqh_first; /* XXX */
+ SIMPLEQ_INIT(&q->q_queue_pending);
mutex_exit(&q->q_mutex);
- workqueue_runlist(wq, &tmp);
+ workqueue_runlist(wq, &q->q_queue_running);
+
+ mutex_enter(&q->q_mutex);
+ KASSERT(!SIMPLEQ_EMPTY(&q->q_queue_running));
+ SIMPLEQ_INIT(&q->q_queue_running);
+ if (__predict_false(q->q_waiter != NULL)) {
+ /* Wake up workqueue_wait */
+ cv_signal(&q->q_cv);
+ }
+ mutex_exit(&q->q_mutex);
}
}
@@ -159,7 +166,8 @@ workqueue_initqueue(struct workqueue *wq
mutex_init(&q->q_mutex, MUTEX_DEFAULT, ipl);
cv_init(&q->q_cv, wq->wq_name);
- SIMPLEQ_INIT(&q->q_queue);
+ SIMPLEQ_INIT(&q->q_queue_pending);
+ SIMPLEQ_INIT(&q->q_queue_running);
ktf = ((wq->wq_flags & WQ_MPSAFE) != 0 ? KTHREAD_MPSAFE : 0);
if (wq->wq_prio < PRI_KERNEL)
ktf |= KTHREAD_TS;
@@ -194,7 +202,7 @@ workqueue_exit(struct work *wk, void *ar
*/
KASSERT(q->q_worker == curlwp);
- KASSERT(SIMPLEQ_EMPTY(&q->q_queue));
+ KASSERT(SIMPLEQ_EMPTY(&q->q_queue_pending));
mutex_enter(&q->q_mutex);
q->q_worker = NULL;
cv_signal(&q->q_cv);
@@ -210,10 +218,10 @@ workqueue_finiqueue(struct workqueue *wq
KASSERT(wq->wq_func == workqueue_exit);
wqe.wqe_q = q;
- KASSERT(SIMPLEQ_EMPTY(&q->q_queue));
+ KASSERT(SIMPLEQ_EMPTY(&q->q_queue_pending));
KASSERT(q->q_worker != NULL);
mutex_enter(&q->q_mutex);
- SIMPLEQ_INSERT_TAIL(&q->q_queue, &wqe.wqe_wk, wk_entry);
+ SIMPLEQ_INSERT_TAIL(&q->q_queue_pending, &wqe.wqe_wk, wk_entry);
cv_signal(&q->q_cv);
while (q->q_worker != NULL) {
cv_wait(&q->q_cv, &q->q_mutex);
@@ -271,6 +279,64 @@ workqueue_create(struct workqueue **wqp,
return error;
}
+static bool
+workqueue_q_wait(struct workqueue_queue *q, work_impl_t *wk_target)
+{
+ work_impl_t *wk;
+ bool found = false;
+
+ mutex_enter(&q->q_mutex);
+ again:
+ SIMPLEQ_FOREACH(wk, &q->q_queue_pending, wk_entry) {
+ if (wk == wk_target)
+ goto found;
+ }
+ SIMPLEQ_FOREACH(wk, &q->q_queue_running, wk_entry) {
+ if (wk == wk_target)
+ goto found;
+ }
+ found:
+ if (wk != NULL) {
+ found = true;
+ KASSERT(q->q_waiter == NULL);
+ q->q_waiter = wk;
+ cv_wait(&q->q_cv, &q->q_mutex);
+ goto again;
+ }
+ if (q->q_waiter != NULL)
+ q->q_waiter = NULL;
+ mutex_exit(&q->q_mutex);
+
+ return found;
+}
+
+/*
+ * Wait for a specified work to finish. The caller must ensure that no new
+ * work will be enqueued before calling workqueue_wait. Note that if the
+ * workqueue is WQ_PERCPU, the caller can enqueue a new work to another queue
+ * other than the waiting queue.
+ */
+void
+workqueue_wait(struct workqueue *wq, struct work *wk)
+{
+ struct workqueue_queue *q;
+ bool found;
+
+ if (ISSET(wq->wq_flags, WQ_PERCPU)) {
+ struct cpu_info *ci;
+ CPU_INFO_ITERATOR cii;
+ for (CPU_INFO_FOREACH(cii, ci)) {
+ q = workqueue_queue_lookup(wq, ci);
+ found = workqueue_q_wait(q, (work_impl_t *)wk);
+ if (found)
+ break;
+ }
+ } else {
+ q = workqueue_queue_lookup(wq, NULL);
+ (void) workqueue_q_wait(q, (work_impl_t *)wk);
+ }
+}
+
void
workqueue_destroy(struct workqueue *wq)
{
@@ -298,7 +364,8 @@ workqueue_enqueue(struct workqueue *wq,
q = workqueue_queue_lookup(wq, ci);
mutex_enter(&q->q_mutex);
- SIMPLEQ_INSERT_TAIL(&q->q_queue, wk, wk_entry);
+ KASSERT(q->q_waiter == NULL);
+ SIMPLEQ_INSERT_TAIL(&q->q_queue_pending, wk, wk_entry);
cv_signal(&q->q_cv);
mutex_exit(&q->q_mutex);
}
Index: src/sys/sys/workqueue.h
diff -u src/sys/sys/workqueue.h:1.9 src/sys/sys/workqueue.h:1.10
--- src/sys/sys/workqueue.h:1.9 Fri Oct 19 12:16:48 2007
+++ src/sys/sys/workqueue.h Thu Dec 28 07:00:52 2017
@@ -1,4 +1,4 @@
-/* $NetBSD: workqueue.h,v 1.9 2007/10/19 12:16:48 ad Exp $ */
+/* $NetBSD: workqueue.h,v 1.10 2017/12/28 07:00:52 ozaki-r Exp $ */
/*-
* Copyright (c)2002, 2005 YAMAMOTO Takashi,
@@ -51,6 +51,7 @@ struct workqueue;
int workqueue_create(struct workqueue **, const char *,
void (*)(struct work *, void *), void *, pri_t, int, int);
void workqueue_destroy(struct workqueue *);
+void workqueue_wait(struct workqueue *, struct work *);
void workqueue_enqueue(struct workqueue *, struct work *, struct cpu_info *);
