s390/vtimer: rework virtual timer interface

The current virtual timer interface is inherently per-cpu and hard to
use. The sole user of the interface is appldata which uses it to execute
a function after a specific amount of cputime has been used over all cpus.

Rework the virtual timer interface to hook into the cputime accounting.
This makes the interface independent from the CPU timer interrupts, and
makes the virtual timers global as opposed to per-cpu.
Overall the code is greatly simplified. The downside is that the accuracy
is not as good as the original implementation, but it is still good enough
for appldata.

Reviewed-by: Jan Glauber <jang@linux.vnet.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

3 files changed, 37 insertions, 53 deletions

diff --git a/arch/s390/include/asm/cputime.h b/arch/s390/include/asm/cputime.h
index 357ea7b..8709bde 100644
--- a/arch/s390/include/asm/cputime.h
+++ b/arch/s390/include/asm/cputime.h
@@ -168,9 +168,11 @@ struct s390_idle_data {
 	int nohz_delay;
 	unsigned int sequence;
 	unsigned long long idle_count;
-	unsigned long long idle_enter;
-	unsigned long long idle_exit;
 	unsigned long long idle_time;
+	unsigned long long clock_idle_enter;
+	unsigned long long clock_idle_exit;
+	unsigned long long timer_idle_enter;
+	unsigned long long timer_idle_exit;
 };
 
 DECLARE_PER_CPU(struct s390_idle_data, s390_idle);
diff --git a/arch/s390/include/asm/timer.h b/arch/s390/include/asm/timer.h
deleted file mode 100644
index 15d6479..0000000
--- a/arch/s390/include/asm/timer.h
+++ /dev/null
@@ -1,51 +0,0 @@
-/*
- *  include/asm-s390/timer.h
- *
- *  (C) Copyright IBM Corp. 2003,2006
- *  Virtual CPU timer
- *
- *  Author: Jan Glauber (jang@de.ibm.com)
- */
-
-#ifndef _ASM_S390_TIMER_H
-#define _ASM_S390_TIMER_H
-
-#include <linux/timer.h>
-
-#define VTIMER_MAX_SLICE (0x7ffffffffffff000LL)
-
-struct vtimer_list {
-	struct list_head entry;
-
-	int cpu;
-	__u64 expires;
-	__u64 interval;
-
-	void (*function)(unsigned long);
-	unsigned long data;
-};
-
-/* the vtimer value will wrap after ca. 71 years */
-struct vtimer_queue {
-	struct list_head list;
-	spinlock_t lock;
-	__u64 timer;		/* last programmed timer */
-	__u64 elapsed;		/* elapsed time of timer expire values */
-	__u64 idle_enter;	/* cpu timer on idle enter */
-	__u64 idle_exit;	/* cpu timer on idle exit */
-};
-
-extern void init_virt_timer(struct vtimer_list *timer);
-extern void add_virt_timer(void *new);
-extern void add_virt_timer_periodic(void *new);
-extern int mod_virt_timer(struct vtimer_list *timer, __u64 expires);
-extern int mod_virt_timer_periodic(struct vtimer_list *timer, __u64 expires);
-extern int del_virt_timer(struct vtimer_list *timer);
-
-extern void init_cpu_vtimer(void);
-extern void vtime_init(void);
-
-extern void vtime_stop_cpu(void);
-extern void vtime_start_leave(void);
-
-#endif /* _ASM_S390_TIMER_H */
diff --git a/arch/s390/include/asm/vtimer.h b/arch/s390/include/asm/vtimer.h
new file mode 100644
index 0000000..bfe25d5
--- /dev/null
+++ b/arch/s390/include/asm/vtimer.h
@@ -0,0 +1,33 @@
+/*
+ *  Copyright IBM Corp. 2003, 2012
+ *  Virtual CPU timer
+ *
+ *  Author(s): Jan Glauber <jan.glauber@de.ibm.com>
+ */
+
+#ifndef _ASM_S390_TIMER_H
+#define _ASM_S390_TIMER_H
+
+#define VTIMER_MAX_SLICE (0x7fffffffffffffffULL)
+
+struct vtimer_list {
+	struct list_head entry;
+	u64 expires;
+	u64 interval;
+	void (*function)(unsigned long);
+	unsigned long data;
+};
+
+extern void init_virt_timer(struct vtimer_list *timer);
+extern void add_virt_timer(struct vtimer_list *timer);
+extern void add_virt_timer_periodic(struct vtimer_list *timer);
+extern int mod_virt_timer(struct vtimer_list *timer, u64 expires);
+extern int mod_virt_timer_periodic(struct vtimer_list *timer, u64 expires);
+extern int del_virt_timer(struct vtimer_list *timer);
+
+extern void init_cpu_vtimer(void);
+extern void vtime_init(void);
+
+extern void vtime_stop_cpu(void);
+
+#endif /* _ASM_S390_TIMER_H */