1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
|
From 3cf7a90f946a893311cfe44a8b06ecffeb370b79 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Fri, 3 Jul 2009 08:44:32 -0500
Subject: [PATCH] hrtimer: Fix softirq device reprogramming
commit b275903a1dc4442383a05137ea6a8985605291e9 in tip.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
---
kernel/hrtimer.c | 60 +++++++++++++++++++++++++++++++++++++++--------------
1 files changed, 44 insertions(+), 16 deletions(-)
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index 834e1bc..f05d9ce 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -563,7 +563,6 @@ static int hrtimer_reprogram(struct hrtimer *timer,
WARN_ON_ONCE(hrtimer_get_expires_tv64(timer) < 0);
-#ifndef CONFIG_PREEMPT_RT
/*
* When the callback is running, we do not reprogram the clock event
* device. The timer callback is either running on a different CPU or
@@ -572,15 +571,6 @@ static int hrtimer_reprogram(struct hrtimer *timer,
*/
if (hrtimer_callback_running(timer))
return 0;
-#else
- /*
- * preempt-rt changes the rules here as long as we have not
- * solved the callback problem. For softirq based timers we
- * need to allow reprogramming.
- */
- if (hrtimer_callback_running(timer) && timer->irqsafe)
- return 0;
-#endif
/*
* CLOCK_REALTIME timer might be requested with an absolute
@@ -1309,6 +1299,49 @@ static void __run_hrtimer(struct hrtimer *timer, ktime_t *now)
#ifdef CONFIG_PREEMPT_RT
+
+static void hrtimer_rt_reprogram(int restart, struct hrtimer *timer,
+ struct hrtimer_clock_base *base)
+{
+ /*
+ * Note, we clear the callback flag before we requeue the
+ * timer otherwise we trigger the callback_running() check
+ * in hrtimer_reprogram().
+ */
+ timer->state &= ~HRTIMER_STATE_CALLBACK;
+
+ if (restart != HRTIMER_NORESTART) {
+ BUG_ON(hrtimer_active(timer));
+ /*
+ * Enqueue the timer, if it's the leftmost timer then
+ * we need to reprogram it.
+ */
+ if (!enqueue_hrtimer(timer, base))
+ return;
+
+ if (hrtimer_reprogram(timer, base))
+ goto requeue;
+
+ } else if (hrtimer_active(timer)) {
+ /*
+ * If the timer was rearmed on another CPU, reprogram
+ * the event device.
+ */
+ if (base->first == &timer->node &&
+ hrtimer_reprogram(timer, base))
+ goto requeue;
+ }
+ return;
+
+requeue:
+ /*
+ * Timer is expired. Thus move it from tree to pending list
+ * again.
+ */
+ __remove_hrtimer(timer, base, timer->state, 0);
+ list_add_tail(&timer->cb_entry, &base->expired);
+}
+
/*
* The changes in mainline which removed the callback modes from
* hrtimer are not yet working with -rt. The non wakeup_process()
@@ -1348,11 +1381,7 @@ static void hrtimer_rt_run_pending(void)
restart = fn(timer);
raw_spin_lock_irq(&cpu_base->lock);
- if (restart != HRTIMER_NORESTART) {
- BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
- enqueue_hrtimer(timer, base);
- }
- timer->state &= ~HRTIMER_STATE_CALLBACK;
+ hrtimer_rt_reprogram(restart, timer, base);
}
}
@@ -1553,7 +1582,6 @@ static inline void __hrtimer_peek_ahead_timers(void) { }
static void run_hrtimer_softirq(struct softirq_action *h)
{
- hrtimer_peek_ahead_timers();
hrtimer_rt_run_pending();
}
--
1.7.0.4
|
