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-rw-r--r--arch/s390/kernel/vtime.c370
1 files changed, 131 insertions, 239 deletions
diff --git a/arch/s390/kernel/vtime.c b/arch/s390/kernel/vtime.c
index 39ebff5..4fc97b4 100644
--- a/arch/s390/kernel/vtime.c
+++ b/arch/s390/kernel/vtime.c
@@ -1,71 +1,82 @@
/*
- * arch/s390/kernel/vtime.c
* Virtual cpu timer based timer functions.
*
- * S390 version
- * Copyright (C) 2004 IBM Deutschland Entwicklung GmbH, IBM Corporation
+ * Copyright IBM Corp. 2004, 2012
* Author(s): Jan Glauber <jan.glauber@de.ibm.com>
*/
-#include <linux/module.h>
+#include <linux/kernel_stat.h>
+#include <linux/notifier.h>
+#include <linux/kprobes.h>
+#include <linux/export.h>
#include <linux/kernel.h>
-#include <linux/time.h>
-#include <linux/delay.h>
-#include <linux/init.h>
-#include <linux/smp.h>
-#include <linux/types.h>
#include <linux/timex.h>
-#include <linux/notifier.h>
-#include <linux/kernel_stat.h>
-#include <linux/rcupdate.h>
-#include <linux/posix-timers.h>
+#include <linux/types.h>
+#include <linux/time.h>
#include <linux/cpu.h>
-#include <linux/kprobes.h>
+#include <linux/smp.h>
-#include <asm/timer.h>
#include <asm/irq_regs.h>
#include <asm/cputime.h>
+#include <asm/vtimer.h>
#include <asm/irq.h>
#include "entry.h"
-static DEFINE_PER_CPU(struct vtimer_queue, virt_cpu_timer);
+static void virt_timer_expire(void);
DEFINE_PER_CPU(struct s390_idle_data, s390_idle);
-static inline __u64 get_vtimer(void)
+static LIST_HEAD(virt_timer_list);
+static DEFINE_SPINLOCK(virt_timer_lock);
+static atomic64_t virt_timer_current;
+static atomic64_t virt_timer_elapsed;
+
+static inline u64 get_vtimer(void)
{
- __u64 timer;
+ u64 timer;
- asm volatile("STPT %0" : "=m" (timer));
+ asm volatile("stpt %0" : "=m" (timer));
return timer;
}
-static inline void set_vtimer(__u64 expires)
+static inline void set_vtimer(u64 expires)
{
- __u64 timer;
+ u64 timer;
- asm volatile (" STPT %0\n" /* Store current cpu timer value */
- " SPT %1" /* Set new value immediately afterwards */
- : "=m" (timer) : "m" (expires) );
+ asm volatile(
+ " stpt %0\n" /* Store current cpu timer value */
+ " spt %1" /* Set new value imm. afterwards */
+ : "=m" (timer) : "m" (expires));
S390_lowcore.system_timer += S390_lowcore.last_update_timer - timer;
S390_lowcore.last_update_timer = expires;
}
+static inline int virt_timer_forward(u64 elapsed)
+{
+ BUG_ON(!irqs_disabled());
+
+ if (list_empty(&virt_timer_list))
+ return 0;
+ elapsed = atomic64_add_return(elapsed, &virt_timer_elapsed);
+ return elapsed >= atomic64_read(&virt_timer_current);
+}
+
/*
* Update process times based on virtual cpu times stored by entry.S
* to the lowcore fields user_timer, system_timer & steal_clock.
*/
-static void do_account_vtime(struct task_struct *tsk, int hardirq_offset)
+static int do_account_vtime(struct task_struct *tsk, int hardirq_offset)
{
struct thread_info *ti = task_thread_info(tsk);
- __u64 timer, clock, user, system, steal;
+ u64 timer, clock, user, system, steal;
timer = S390_lowcore.last_update_timer;
clock = S390_lowcore.last_update_clock;
- asm volatile (" STPT %0\n" /* Store current cpu timer value */
- " STCK %1" /* Store current tod clock value */
- : "=m" (S390_lowcore.last_update_timer),
- "=m" (S390_lowcore.last_update_clock) );
+ asm volatile(
+ " stpt %0\n" /* Store current cpu timer value */
+ " stck %1" /* Store current tod clock value */
+ : "=m" (S390_lowcore.last_update_timer),
+ "=m" (S390_lowcore.last_update_clock));
S390_lowcore.system_timer += timer - S390_lowcore.last_update_timer;
S390_lowcore.steal_timer += S390_lowcore.last_update_clock - clock;
@@ -84,6 +95,8 @@ static void do_account_vtime(struct task_struct *tsk, int hardirq_offset)
S390_lowcore.steal_timer = 0;
account_steal_time(steal);
}
+
+ return virt_timer_forward(user + system);
}
void account_vtime(struct task_struct *prev, struct task_struct *next)
@@ -101,7 +114,8 @@ void account_vtime(struct task_struct *prev, struct task_struct *next)
void account_process_tick(struct task_struct *tsk, int user_tick)
{
- do_account_vtime(tsk, HARDIRQ_OFFSET);
+ if (do_account_vtime(tsk, HARDIRQ_OFFSET))
+ virt_timer_expire();
}
/*
@@ -111,7 +125,7 @@ void account_process_tick(struct task_struct *tsk, int user_tick)
void account_system_vtime(struct task_struct *tsk)
{
struct thread_info *ti = task_thread_info(tsk);
- __u64 timer, system;
+ u64 timer, system;
timer = S390_lowcore.last_update_timer;
S390_lowcore.last_update_timer = get_vtimer();
@@ -121,13 +135,14 @@ void account_system_vtime(struct task_struct *tsk)
S390_lowcore.steal_timer -= system;
ti->system_timer = S390_lowcore.system_timer;
account_system_time(tsk, 0, system, system);
+
+ virt_timer_forward(system);
}
EXPORT_SYMBOL_GPL(account_system_vtime);
void __kprobes vtime_stop_cpu(void)
{
struct s390_idle_data *idle = &__get_cpu_var(s390_idle);
- struct vtimer_queue *vq = &__get_cpu_var(virt_cpu_timer);
unsigned long long idle_time;
unsigned long psw_mask;
@@ -141,7 +156,7 @@ void __kprobes vtime_stop_cpu(void)
idle->nohz_delay = 0;
/* Call the assembler magic in entry.S */
- psw_idle(idle, vq, psw_mask, !list_empty(&vq->list));
+ psw_idle(idle, psw_mask);
/* Reenable preemption tracer. */
start_critical_timings();
@@ -149,9 +164,9 @@ void __kprobes vtime_stop_cpu(void)
/* Account time spent with enabled wait psw loaded as idle time. */
idle->sequence++;
smp_wmb();
- idle_time = idle->idle_exit - idle->idle_enter;
+ idle_time = idle->clock_idle_exit - idle->clock_idle_enter;
+ idle->clock_idle_enter = idle->clock_idle_exit = 0ULL;
idle->idle_time += idle_time;
- idle->idle_enter = idle->idle_exit = 0ULL;
idle->idle_count++;
account_idle_time(idle_time);
smp_wmb();
@@ -167,10 +182,10 @@ cputime64_t s390_get_idle_time(int cpu)
do {
now = get_clock();
sequence = ACCESS_ONCE(idle->sequence);
- idle_enter = ACCESS_ONCE(idle->idle_enter);
- idle_exit = ACCESS_ONCE(idle->idle_exit);
+ idle_enter = ACCESS_ONCE(idle->clock_idle_enter);
+ idle_exit = ACCESS_ONCE(idle->clock_idle_exit);
} while ((sequence & 1) || (idle->sequence != sequence));
- return idle_enter ? ((idle_exit ? : now) - idle_enter) : 0;
+ return idle_enter ? ((idle_exit ?: now) - idle_enter) : 0;
}
/*
@@ -179,11 +194,11 @@ cputime64_t s390_get_idle_time(int cpu)
*/
static void list_add_sorted(struct vtimer_list *timer, struct list_head *head)
{
- struct vtimer_list *event;
+ struct vtimer_list *tmp;
- list_for_each_entry(event, head, entry) {
- if (event->expires > timer->expires) {
- list_add_tail(&timer->entry, &event->entry);
+ list_for_each_entry(tmp, head, entry) {
+ if (tmp->expires > timer->expires) {
+ list_add_tail(&timer->entry, &tmp->entry);
return;
}
}
@@ -191,82 +206,45 @@ static void list_add_sorted(struct vtimer_list *timer, struct list_head *head)
}
/*
- * Do the callback functions of expired vtimer events.
- * Called from within the interrupt handler.
- */
-static void do_callbacks(struct list_head *cb_list)
-{
- struct vtimer_queue *vq;
- struct vtimer_list *event, *tmp;
-
- if (list_empty(cb_list))
- return;
-
- vq = &__get_cpu_var(virt_cpu_timer);
-
- list_for_each_entry_safe(event, tmp, cb_list, entry) {
- list_del_init(&event->entry);
- (event->function)(event->data);
- if (event->interval) {
- /* Recharge interval timer */
- event->expires = event->interval + vq->elapsed;
- spin_lock(&vq->lock);
- list_add_sorted(event, &vq->list);
- spin_unlock(&vq->lock);
- }
- }
-}
-
-/*
- * Handler for the virtual CPU timer.
+ * Handler for expired virtual CPU timer.
*/
-static void do_cpu_timer_interrupt(struct ext_code ext_code,
- unsigned int param32, unsigned long param64)
+static void virt_timer_expire(void)
{
- struct vtimer_queue *vq;
- struct vtimer_list *event, *tmp;
- struct list_head cb_list; /* the callback queue */
- __u64 elapsed, next;
-
- kstat_cpu(smp_processor_id()).irqs[EXTINT_TMR]++;
- INIT_LIST_HEAD(&cb_list);
- vq = &__get_cpu_var(virt_cpu_timer);
-
- /* walk timer list, fire all expired events */
- spin_lock(&vq->lock);
-
- elapsed = vq->elapsed + (vq->timer - S390_lowcore.async_enter_timer);
- BUG_ON((s64) elapsed < 0);
- vq->elapsed = 0;
- list_for_each_entry_safe(event, tmp, &vq->list, entry) {
- if (event->expires < elapsed)
+ struct vtimer_list *timer, *tmp;
+ unsigned long elapsed;
+ LIST_HEAD(cb_list);
+
+ /* walk timer list, fire all expired timers */
+ spin_lock(&virt_timer_lock);
+ elapsed = atomic64_read(&virt_timer_elapsed);
+ list_for_each_entry_safe(timer, tmp, &virt_timer_list, entry) {
+ if (timer->expires < elapsed)
/* move expired timer to the callback queue */
- list_move_tail(&event->entry, &cb_list);
+ list_move_tail(&timer->entry, &cb_list);
else
- event->expires -= elapsed;
+ timer->expires -= elapsed;
}
- spin_unlock(&vq->lock);
-
- do_callbacks(&cb_list);
-
- /* next event is first in list */
- next = VTIMER_MAX_SLICE;
- spin_lock(&vq->lock);
- if (!list_empty(&vq->list)) {
- event = list_first_entry(&vq->list, struct vtimer_list, entry);
- next = event->expires;
+ if (!list_empty(&virt_timer_list)) {
+ timer = list_first_entry(&virt_timer_list,
+ struct vtimer_list, entry);
+ atomic64_set(&virt_timer_current, timer->expires);
+ }
+ atomic64_sub(elapsed, &virt_timer_elapsed);
+ spin_unlock(&virt_timer_lock);
+
+ /* Do callbacks and recharge periodic timers */
+ list_for_each_entry_safe(timer, tmp, &cb_list, entry) {
+ list_del_init(&timer->entry);
+ timer->function(timer->data);
+ if (timer->interval) {
+ /* Recharge interval timer */
+ timer->expires = timer->interval +
+ atomic64_read(&virt_timer_elapsed);
+ spin_lock(&virt_timer_lock);
+ list_add_sorted(timer, &virt_timer_list);
+ spin_unlock(&virt_timer_lock);
+ }
}
- spin_unlock(&vq->lock);
- /*
- * To improve precision add the time spent by the
- * interrupt handler to the elapsed time.
- * Note: CPU timer counts down and we got an interrupt,
- * the current content is negative
- */
- elapsed = S390_lowcore.async_enter_timer - get_vtimer();
- set_vtimer(next - elapsed);
- vq->timer = next - elapsed;
- vq->elapsed = elapsed;
}
void init_virt_timer(struct vtimer_list *timer)
@@ -278,179 +256,108 @@ EXPORT_SYMBOL(init_virt_timer);
static inline int vtimer_pending(struct vtimer_list *timer)
{
- return (!list_empty(&timer->entry));
+ return !list_empty(&timer->entry);
}
-/*
- * this function should only run on the specified CPU
- */
static void internal_add_vtimer(struct vtimer_list *timer)
{
- struct vtimer_queue *vq;
- unsigned long flags;
- __u64 left, expires;
-
- vq = &per_cpu(virt_cpu_timer, timer->cpu);
- spin_lock_irqsave(&vq->lock, flags);
-
- BUG_ON(timer->cpu != smp_processor_id());
-
- if (list_empty(&vq->list)) {
- /* First timer on this cpu, just program it. */
- list_add(&timer->entry, &vq->list);
- set_vtimer(timer->expires);
- vq->timer = timer->expires;
- vq->elapsed = 0;
+ if (list_empty(&virt_timer_list)) {
+ /* First timer, just program it. */
+ atomic64_set(&virt_timer_current, timer->expires);
+ atomic64_set(&virt_timer_elapsed, 0);
+ list_add(&timer->entry, &virt_timer_list);
} else {
- /* Check progress of old timers. */
- expires = timer->expires;
- left = get_vtimer();
- if (likely((s64) expires < (s64) left)) {
+ /* Update timer against current base. */
+ timer->expires += atomic64_read(&virt_timer_elapsed);
+ if (likely((s64) timer->expires <
+ (s64) atomic64_read(&virt_timer_current)))
/* The new timer expires before the current timer. */
- set_vtimer(expires);
- vq->elapsed += vq->timer - left;
- vq->timer = expires;
- } else {
- vq->elapsed += vq->timer - left;
- vq->timer = left;
- }
- /* Insert new timer into per cpu list. */
- timer->expires += vq->elapsed;
- list_add_sorted(timer, &vq->list);
+ atomic64_set(&virt_timer_current, timer->expires);
+ /* Insert new timer into the list. */
+ list_add_sorted(timer, &virt_timer_list);
}
-
- spin_unlock_irqrestore(&vq->lock, flags);
- /* release CPU acquired in prepare_vtimer or mod_virt_timer() */
- put_cpu();
}
-static inline void prepare_vtimer(struct vtimer_list *timer)
+static void __add_vtimer(struct vtimer_list *timer, int periodic)
{
- BUG_ON(!timer->function);
- BUG_ON(!timer->expires || timer->expires > VTIMER_MAX_SLICE);
- BUG_ON(vtimer_pending(timer));
- timer->cpu = get_cpu();
+ unsigned long flags;
+
+ timer->interval = periodic ? timer->expires : 0;
+ spin_lock_irqsave(&virt_timer_lock, flags);
+ internal_add_vtimer(timer);
+ spin_unlock_irqrestore(&virt_timer_lock, flags);
}
/*
* add_virt_timer - add an oneshot virtual CPU timer
*/
-void add_virt_timer(void *new)
+void add_virt_timer(struct vtimer_list *timer)
{
- struct vtimer_list *timer;
-
- timer = (struct vtimer_list *)new;
- prepare_vtimer(timer);
- timer->interval = 0;
- internal_add_vtimer(timer);
+ __add_vtimer(timer, 0);
}
EXPORT_SYMBOL(add_virt_timer);
/*
* add_virt_timer_int - add an interval virtual CPU timer
*/
-void add_virt_timer_periodic(void *new)
+void add_virt_timer_periodic(struct vtimer_list *timer)
{
- struct vtimer_list *timer;
-
- timer = (struct vtimer_list *)new;
- prepare_vtimer(timer);
- timer->interval = timer->expires;
- internal_add_vtimer(timer);
+ __add_vtimer(timer, 1);
}
EXPORT_SYMBOL(add_virt_timer_periodic);
-static int __mod_vtimer(struct vtimer_list *timer, __u64 expires, int periodic)
+static int __mod_vtimer(struct vtimer_list *timer, u64 expires, int periodic)
{
- struct vtimer_queue *vq;
unsigned long flags;
- int cpu;
+ int rc;
BUG_ON(!timer->function);
- BUG_ON(!expires || expires > VTIMER_MAX_SLICE);
if (timer->expires == expires && vtimer_pending(timer))
return 1;
-
- cpu = get_cpu();
- vq = &per_cpu(virt_cpu_timer, cpu);
-
- /* disable interrupts before test if timer is pending */
- spin_lock_irqsave(&vq->lock, flags);
-
- /* if timer isn't pending add it on the current CPU */
- if (!vtimer_pending(timer)) {
- spin_unlock_irqrestore(&vq->lock, flags);
-
- if (periodic)
- timer->interval = expires;
- else
- timer->interval = 0;
- timer->expires = expires;
- timer->cpu = cpu;
- internal_add_vtimer(timer);
- return 0;
- }
-
- /* check if we run on the right CPU */
- BUG_ON(timer->cpu != cpu);
-
- list_del_init(&timer->entry);
+ spin_lock_irqsave(&virt_timer_lock, flags);
+ rc = vtimer_pending(timer);
+ if (rc)
+ list_del_init(&timer->entry);
+ timer->interval = periodic ? expires : 0;
timer->expires = expires;
- if (periodic)
- timer->interval = expires;
-
- /* the timer can't expire anymore so we can release the lock */
- spin_unlock_irqrestore(&vq->lock, flags);
internal_add_vtimer(timer);
- return 1;
+ spin_unlock_irqrestore(&virt_timer_lock, flags);
+ return rc;
}
/*
- * If we change a pending timer the function must be called on the CPU
- * where the timer is running on.
- *
* returns whether it has modified a pending timer (1) or not (0)
*/
-int mod_virt_timer(struct vtimer_list *timer, __u64 expires)
+int mod_virt_timer(struct vtimer_list *timer, u64 expires)
{
return __mod_vtimer(timer, expires, 0);
}
EXPORT_SYMBOL(mod_virt_timer);
/*
- * If we change a pending timer the function must be called on the CPU
- * where the timer is running on.
- *
* returns whether it has modified a pending timer (1) or not (0)
*/
-int mod_virt_timer_periodic(struct vtimer_list *timer, __u64 expires)
+int mod_virt_timer_periodic(struct vtimer_list *timer, u64 expires)
{
return __mod_vtimer(timer, expires, 1);
}
EXPORT_SYMBOL(mod_virt_timer_periodic);
/*
- * delete a virtual timer
+ * Delete a virtual timer.
*
* returns whether the deleted timer was pending (1) or not (0)
*/
int del_virt_timer(struct vtimer_list *timer)
{
unsigned long flags;
- struct vtimer_queue *vq;
- /* check if timer is pending */
if (!vtimer_pending(timer))
return 0;
-
- vq = &per_cpu(virt_cpu_timer, timer->cpu);
- spin_lock_irqsave(&vq->lock, flags);
-
- /* we don't interrupt a running timer, just let it expire! */
+ spin_lock_irqsave(&virt_timer_lock, flags);
list_del_init(&timer->entry);
-
- spin_unlock_irqrestore(&vq->lock, flags);
+ spin_unlock_irqrestore(&virt_timer_lock, flags);
return 1;
}
EXPORT_SYMBOL(del_virt_timer);
@@ -458,20 +365,10 @@ EXPORT_SYMBOL(del_virt_timer);
/*
* Start the virtual CPU timer on the current CPU.
*/
-void init_cpu_vtimer(void)
+void __cpuinit init_cpu_vtimer(void)
{
- struct vtimer_queue *vq;
-
- /* initialize per cpu vtimer structure */
- vq = &__get_cpu_var(virt_cpu_timer);
- INIT_LIST_HEAD(&vq->list);
- spin_lock_init(&vq->lock);
-
- /* enable cpu timer interrupts */
- __ctl_set_bit(0,10);
-
/* set initial cpu timer */
- set_vtimer(0x7fffffffffffffffULL);
+ set_vtimer(VTIMER_MAX_SLICE);
}
static int __cpuinit s390_nohz_notify(struct notifier_block *self,
@@ -493,12 +390,7 @@ static int __cpuinit s390_nohz_notify(struct notifier_block *self,
void __init vtime_init(void)
{
- /* request the cpu timer external interrupt */
- if (register_external_interrupt(0x1005, do_cpu_timer_interrupt))
- panic("Couldn't request external interrupt 0x1005");
-
/* Enable cpu timer interrupts on the boot cpu. */
init_cpu_vtimer();
cpu_notifier(s390_nohz_notify, 0);
}
-