CVS commit: src/sys/kern

[Taylor R Campbell]

Module Name:    src
Committed By:   riastradh
Date:           Wed Aug  9 08:23:45 UTC 2023

Modified Files:
        src/sys/kern: subr_workqueue.c

Log Message:
workqueue(9): Avoid unnecessary mutex_exit/enter cycle each loop.


To generate a diff of this commit:
cvs rdiff -u -r1.44 -r1.45 src/sys/kern/subr_workqueue.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.


Modified files:

Index: src/sys/kern/subr_workqueue.c
diff -u src/sys/kern/subr_workqueue.c:1.44 src/sys/kern/subr_workqueue.c:1.45
--- src/sys/kern/subr_workqueue.c:1.44	Wed Aug  9 08:23:35 2023
+++ src/sys/kern/subr_workqueue.c	Wed Aug  9 08:23:45 2023
@@ -1,4 +1,4 @@
-/*	$NetBSD: subr_workqueue.c,v 1.44 2023/08/09 08:23:35 riastradh Exp $	*/
+/*	$NetBSD: subr_workqueue.c,v 1.45 2023/08/09 08:23:45 riastradh 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 1.44 2023/08/09 08:23:35 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: subr_workqueue.c,v 1.45 2023/08/09 08:23:45 riastradh Exp $");
 
 #include <sys/param.h>
 #include <sys/cpu.h>
@@ -162,12 +162,12 @@ workqueue_worker(void *cookie)
 
 	if (wq->wq_flags & WQ_FPU)
 		s = kthread_fpu_enter();
+	mutex_enter(&q->q_mutex);
 	for (;;) {
 		struct workqhead tmp;
 
 		SIMPLEQ_INIT(&tmp);
 
-		mutex_enter(&q->q_mutex);
 		while (SIMPLEQ_EMPTY(&q->q_queue_pending))
 			cv_wait(&q->q_cv, &q->q_mutex);
 		SIMPLEQ_CONCAT(&tmp, &q->q_queue_pending);
@@ -190,8 +190,8 @@ workqueue_worker(void *cookie)
 		KASSERTMSG(q->q_gen & 1, "q=%p gen=%"PRIu64, q, q->q_gen);
 		q->q_gen++;
 		cv_broadcast(&q->q_cv);
-		mutex_exit(&q->q_mutex);
 	}
+	mutex_exit(&q->q_mutex);
 	if (wq->wq_flags & WQ_FPU)
 		kthread_fpu_exit(s);
 }