[.joined/src/trunk]: .joined/src sysmon(9): New sysmon_task_queue_barrier(pri...

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/.joined/src/rev/aaaf8c1082d5
branches:  trunk
changeset: 359335:aaaf8c1082d5
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Fri Dec 31 14:22:10 2021 +0000

description:
sysmon(9): New sysmon_task_queue_barrier(pri) function.

This waits for the completion of all tasks at priority pri or lower
that are currently queued at the time of the call.

diffstat:

 share/man/man9/sysmon_taskq.9 |  12 ++++-
 sys/dev/sysmon/sysmon_taskq.c |  93 +++++++++++++++++++++++++++++++++++-------
 sys/dev/sysmon/sysmon_taskq.h |   3 +-
 3 files changed, 89 insertions(+), 19 deletions(-)

diffs (188 lines):

diff -r a047dd7bbcf5 -r aaaf8c1082d5 share/man/man9/sysmon_taskq.9
--- a/share/man/man9/sysmon_taskq.9     Fri Dec 31 14:20:56 2021 +0000
+++ b/share/man/man9/sysmon_taskq.9     Fri Dec 31 14:22:10 2021 +0000
@@ -1,4 +1,4 @@
-.\" $NetBSD: sysmon_taskq.9,v 1.8 2014/03/18 18:20:40 riastradh Exp $
+.\" $NetBSD: sysmon_taskq.9,v 1.9 2021/12/31 14:22:10 riastradh Exp $
 .\"
 .\" Copyright (c) 2010 The NetBSD Foundation, Inc.
 .\" All rights reserved.
@@ -43,6 +43,8 @@
 .Fn sysmon_task_queue_fini "void"
 .Ft int
 .Fn sysmon_task_queue_sched "u_int pri" "void (*func)(void *)" "void *arg"
+.Ft void
+.Fn sysmon_task_queue_barrier "u_int pri"
 .Sh DESCRIPTION
 The machine-independent
 .Nm
@@ -67,7 +69,7 @@
 .Pp
 The
 .Fn sysmon_task_queue_sched
-enqueues
+function enqueues
 .Fa func
 to be executed at the priority
 .Fa pri .
@@ -78,6 +80,12 @@
 .Fa func
 is specified by
 .Fa arg .
+.Pp
+The
+.Fn sysmon_task_queue_barrier
+function waits for the completion of all tasks at
+.Fa pri
+or lower currently queued at the time of the call.
 .Sh RETURN VALUES
 Upon successful completion,
 .Fn sysmon_task_queue_sched
diff -r a047dd7bbcf5 -r aaaf8c1082d5 sys/dev/sysmon/sysmon_taskq.c
--- a/sys/dev/sysmon/sysmon_taskq.c     Fri Dec 31 14:20:56 2021 +0000
+++ b/sys/dev/sysmon/sysmon_taskq.c     Fri Dec 31 14:22:10 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: sysmon_taskq.c,v 1.21 2021/12/31 11:05:41 riastradh Exp $      */
+/*     $NetBSD: sysmon_taskq.c,v 1.22 2021/12/31 14:22:11 riastradh Exp $      */
 
 /*
  * Copyright (c) 2001, 2003 Wasabi Systems, Inc.
@@ -41,7 +41,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: sysmon_taskq.c,v 1.21 2021/12/31 11:05:41 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: sysmon_taskq.c,v 1.22 2021/12/31 14:22:11 riastradh Exp $");
 
 #include <sys/param.h>
 #include <sys/malloc.h>
@@ -202,6 +202,26 @@
        kthread_exit(0);
 }
 
+static void
+sysmon_task_queue_sched_task(struct sysmon_task *st)
+{
+       struct sysmon_task *lst;
+
+       mutex_enter(&sysmon_task_queue_mtx);
+       TAILQ_FOREACH(lst, &sysmon_task_queue, st_list) {
+               if (st->st_pri > lst->st_pri) {
+                       TAILQ_INSERT_BEFORE(lst, st, st_list);
+                       break;
+               }
+       }
+
+       if (lst == NULL)
+               TAILQ_INSERT_TAIL(&sysmon_task_queue, st, st_list);
+
+       cv_broadcast(&sysmon_task_queue_cv);
+       mutex_exit(&sysmon_task_queue_mtx);
+}
+
 /*
  * sysmon_task_queue_sched:
  *
@@ -210,7 +230,7 @@
 int
 sysmon_task_queue_sched(u_int pri, void (*func)(void *), void *arg)
 {
-       struct sysmon_task *st, *lst;
+       struct sysmon_task *st;
 
        (void)RUN_ONCE(&once_tq, tq_preinit);
 
@@ -229,23 +249,64 @@
        st->st_arg = arg;
        st->st_pri = pri;
 
-       mutex_enter(&sysmon_task_queue_mtx);
-       TAILQ_FOREACH(lst, &sysmon_task_queue, st_list) {
-               if (st->st_pri > lst->st_pri) {
-                       TAILQ_INSERT_BEFORE(lst, st, st_list);
-                       break;
-               }
-       }
-
-       if (lst == NULL)
-               TAILQ_INSERT_TAIL(&sysmon_task_queue, st, st_list);
-
-       cv_broadcast(&sysmon_task_queue_cv);
-       mutex_exit(&sysmon_task_queue_mtx);
+       sysmon_task_queue_sched_task(st);
 
        return 0;
 }
 
+struct tqbarrier {
+       kmutex_t        lock;
+       kcondvar_t      cv;
+       bool            done;
+};
+
+static void
+tqbarrier_task(void *cookie)
+{
+       struct tqbarrier *bar = cookie;
+
+       mutex_enter(&bar->lock);
+       bar->done = true;
+       cv_broadcast(&bar->cv);
+       mutex_exit(&bar->lock);
+}
+
+/*
+ * sysmon_task_queue_barrier:
+ *
+ *     Wait for the completion of all tasks at priority pri or lower
+ *     currently queued at the time of the call.
+ */
+void
+sysmon_task_queue_barrier(u_int pri)
+{
+       struct sysmon_task st;
+       struct tqbarrier bar;
+
+       (void)RUN_ONCE(&once_tq, tq_preinit);
+
+       KASSERT(sysmon_task_queue_lwp);
+       KASSERT(curlwp != sysmon_task_queue_lwp);
+
+       mutex_init(&bar.lock, MUTEX_DEFAULT, IPL_NONE);
+       cv_init(&bar.cv, "sysmontq");
+       bar.done = false;
+
+       st.st_func = &tqbarrier_task;
+       st.st_arg = &bar;
+       st.st_pri = pri;
+
+       sysmon_task_queue_sched_task(&st);
+
+       mutex_enter(&bar.lock);
+       while (!bar.done)
+               cv_wait(&bar.cv, &bar.lock);
+       mutex_exit(&bar.lock);
+
+       cv_destroy(&bar.cv);
+       mutex_destroy(&bar.lock);
+}
+
 static int
 sysmon_taskq_modcmd(modcmd_t cmd, void *arg)
 {
diff -r a047dd7bbcf5 -r aaaf8c1082d5 sys/dev/sysmon/sysmon_taskq.h
--- a/sys/dev/sysmon/sysmon_taskq.h     Fri Dec 31 14:20:56 2021 +0000
+++ b/sys/dev/sysmon/sysmon_taskq.h     Fri Dec 31 14:22:10 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: sysmon_taskq.h,v 1.4 2015/04/27 07:51:28 pgoyette Exp $        */
+/*     $NetBSD: sysmon_taskq.h,v 1.5 2021/12/31 14:22:11 riastradh Exp $       */
 
 /*
  * Copyright (c) 2003 Wasabi Systems, Inc.
@@ -41,5 +41,6 @@
 void   sysmon_task_queue_init(void);
 int    sysmon_task_queue_fini(void);
 int    sysmon_task_queue_sched(u_int, void (*)(void *), void *);
+void   sysmon_task_queue_barrier(u_int);
 
 #endif /* _DEV_SYSMON_SYSMON_TASKQ_H_ */