Commit 4c1051e3 authored by Martin Schwidefsky's avatar Martin Schwidefsky

[S390] rework idle code

Whenever the cpu loads an enabled wait PSW it will appear as idle to the
underlying host system. The code in default_idle calls vtime_stop_cpu
which does the necessary voodoo to get the cpu time accounting right.
The udelay code just loads an enabled wait PSW. To correct this rework
the vtime_stop_cpu/vtime_start_cpu logic and move the difficult parts
to entry[64].S, vtime_stop_cpu can now be called from anywhere and
vtime_start_cpu is gone. The correction of the cpu time during wakeup
from an enabled wait PSW is done with a critical section in entry[64].S.
As vtime_start_cpu is gone, s390_idle_check can be removed as well.
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 8b646bd7
......@@ -170,24 +170,17 @@ struct s390_idle_data {
unsigned int sequence;
unsigned long long idle_count;
unsigned long long idle_enter;
unsigned long long idle_exit;
unsigned long long idle_time;
int nohz_delay;
};
DECLARE_PER_CPU(struct s390_idle_data, s390_idle);
void vtime_start_cpu(__u64 int_clock, __u64 enter_timer);
cputime64_t s390_get_idle_time(int cpu);
#define arch_idle_time(cpu) s390_get_idle_time(cpu)
static inline void s390_idle_check(struct pt_regs *regs, __u64 int_clock,
__u64 enter_timer)
{
if (regs->psw.mask & PSW_MASK_WAIT)
vtime_start_cpu(int_clock, enter_timer);
}
static inline int s390_nohz_delay(int cpu)
{
return __get_cpu_var(s390_idle).nohz_delay != 0;
......
......@@ -33,8 +33,8 @@ struct vtimer_queue {
spinlock_t lock;
__u64 timer; /* last programmed timer */
__u64 elapsed; /* elapsed time of timer expire values */
__u64 idle; /* temp var for idle */
int do_spt; /* =1: reprogram cpu timer in idle */
__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);
......
......@@ -8,6 +8,8 @@
#include <linux/kbuild.h>
#include <linux/sched.h>
#include <asm/cputime.h>
#include <asm/timer.h>
#include <asm/vdso.h>
#include <asm/pgtable.h>
#include <asm/system.h>
......@@ -70,6 +72,12 @@ int main(void)
DEFINE(__CLOCK_MONOTONIC, CLOCK_MONOTONIC);
DEFINE(__CLOCK_REALTIME_RES, MONOTONIC_RES_NSEC);
BLANK();
/* idle data offsets */
DEFINE(__IDLE_ENTER, offsetof(struct s390_idle_data, idle_enter));
DEFINE(__IDLE_EXIT, offsetof(struct s390_idle_data, idle_exit));
/* vtimer queue offsets */
DEFINE(__VQ_IDLE_ENTER, offsetof(struct vtimer_queue, idle_enter));
DEFINE(__VQ_IDLE_EXIT, offsetof(struct vtimer_queue, idle_exit));
/* lowcore offsets */
DEFINE(__LC_EXT_PARAMS, offsetof(struct _lowcore, ext_params));
DEFINE(__LC_EXT_CPU_ADDR, offsetof(struct _lowcore, ext_cpu_addr));
......
......@@ -105,14 +105,14 @@ STACK_SIZE = 1 << STACK_SHIFT
.macro ADD64 high,low,timer
al \high,\timer
al \low,\timer+4
al \low,4+\timer
brc 12,.+8
ahi \high,1
.endm
.macro SUB64 high,low,timer
sl \high,\timer
sl \low,\timer+4
sl \low,4+\timer
brc 3,.+8
ahi \high,-1
.endm
......@@ -471,7 +471,6 @@ io_tif:
jnz io_work # there is work to do (signals etc.)
io_restore:
mvc __LC_RETURN_PSW(8),__PT_PSW(%r11)
ni __LC_RETURN_PSW+1,0xfd # clean wait state bit
stpt __LC_EXIT_TIMER
lm %r0,%r15,__PT_R0(%r11)
lpsw __LC_RETURN_PSW
......@@ -612,6 +611,26 @@ ext_skip:
basr %r14,%r1 # call do_extint
j io_return
/*
* Load idle PSW. The second "half" of this function is in cleanup_idle.
*/
ENTRY(psw_idle)
st %r4,__SF_EMPTY(%r15)
basr %r1,0
la %r1,psw_idle_lpsw+4-.(%r1)
st %r1,__SF_EMPTY+4(%r15)
oi __SF_EMPTY+4(%r15),0x80
la %r1,.Lvtimer_max-psw_idle_lpsw-4(%r1)
stck __IDLE_ENTER(%r2)
ltr %r5,%r5
stpt __VQ_IDLE_ENTER(%r3)
jz psw_idle_lpsw
spt 0(%r1)
psw_idle_lpsw:
lpsw __SF_EMPTY(%r15)
br %r14
psw_idle_end:
__critical_end:
/*
......@@ -673,7 +692,6 @@ mcck_skip:
TRACE_IRQS_ON
mcck_return:
mvc __LC_RETURN_MCCK_PSW(8),__PT_PSW(%r11) # move return PSW
ni __LC_RETURN_MCCK_PSW+1,0xfd # clear wait state bit
tm __LC_RETURN_MCCK_PSW+1,0x01 # returning to user ?
jno 0f
lm %r0,%r15,__PT_R0(%r11)
......@@ -748,6 +766,8 @@ cleanup_table:
.long io_tif + 0x80000000
.long io_restore + 0x80000000
.long io_done + 0x80000000
.long psw_idle + 0x80000000
.long psw_idle_end + 0x80000000
cleanup_critical:
cl %r9,BASED(cleanup_table) # system_call
......@@ -766,6 +786,10 @@ cleanup_critical:
jl cleanup_io_tif
cl %r9,BASED(cleanup_table+28) # io_done
jl cleanup_io_restore
cl %r9,BASED(cleanup_table+32) # psw_idle
jl 0f
cl %r9,BASED(cleanup_table+36) # psw_idle_end
jl cleanup_idle
0: br %r14
cleanup_system_call:
......@@ -849,7 +873,6 @@ cleanup_io_restore:
jhe 0f
l %r9,12(%r11) # get saved r11 pointer to pt_regs
mvc __LC_RETURN_PSW(8),__PT_PSW(%r9)
ni __LC_RETURN_PSW+1,0xfd # clear wait state bit
mvc 0(32,%r11),__PT_R8(%r9)
lm %r0,%r7,__PT_R0(%r9)
0: lm %r8,%r9,__LC_RETURN_PSW
......@@ -857,11 +880,52 @@ cleanup_io_restore:
cleanup_io_restore_insn:
.long io_done - 4 + 0x80000000
cleanup_idle:
# copy interrupt clock & cpu timer
mvc __IDLE_EXIT(8,%r2),__LC_INT_CLOCK
mvc __VQ_IDLE_EXIT(8,%r3),__LC_ASYNC_ENTER_TIMER
chi %r11,__LC_SAVE_AREA_ASYNC
je 0f
mvc __IDLE_EXIT(8,%r2),__LC_MCCK_CLOCK
mvc __VQ_IDLE_EXIT(8,%r3),__LC_MCCK_ENTER_TIMER
0: # check if stck has been executed
cl %r9,BASED(cleanup_idle_insn)
jhe 1f
mvc __IDLE_ENTER(8,%r2),__IDLE_EXIT(%r2)
mvc __VQ_IDLE_ENTER(8,%r3),__VQ_IDLE_EXIT(%r3)
j 2f
1: # check if the cpu timer has been reprogrammed
ltr %r5,%r5
jz 2f
spt __VQ_IDLE_ENTER(%r3)
2: # account system time going idle
lm %r9,%r10,__LC_STEAL_TIMER
ADD64 %r9,%r10,__IDLE_ENTER(%r2)
SUB64 %r9,%r10,__LC_LAST_UPDATE_CLOCK
stm %r9,%r10,__LC_STEAL_TIMER
mvc __LC_LAST_UPDATE_CLOCK(8),__IDLE_EXIT(%r2)
lm %r9,%r10,__LC_SYSTEM_TIMER
ADD64 %r9,%r10,__LC_LAST_UPDATE_TIMER
SUB64 %r9,%r10,__VQ_IDLE_ENTER(%r3)
stm %r9,%r10,__LC_SYSTEM_TIMER
mvc __LC_LAST_UPDATE_TIMER(8),__VQ_IDLE_EXIT(%r3)
# prepare return psw
n %r8,BASED(cleanup_idle_wait) # clear wait state bit
l %r9,24(%r11) # return from psw_idle
br %r14
cleanup_idle_insn:
.long psw_idle_lpsw + 0x80000000
cleanup_idle_wait:
.long 0xfffdffff
/*
* Integer constants
*/
.align 4
.Lnr_syscalls: .long NR_syscalls
.Lnr_syscalls:
.long NR_syscalls
.Lvtimer_max:
.quad 0x7fffffffffffffff
/*
* Symbol constants
......
......@@ -4,7 +4,8 @@
#include <linux/types.h>
#include <linux/signal.h>
#include <asm/ptrace.h>
#include <asm/cputime.h>
#include <asm/timer.h>
extern void (*pgm_check_table[128])(struct pt_regs *);
extern void *restart_stack;
......@@ -16,6 +17,8 @@ void io_int_handler(void);
void mcck_int_handler(void);
void restart_int_handler(void);
void restart_call_handler(void);
void psw_idle(struct s390_idle_data *, struct vtimer_queue *,
unsigned long, int);
asmlinkage long do_syscall_trace_enter(struct pt_regs *regs);
asmlinkage void do_syscall_trace_exit(struct pt_regs *regs);
......
......@@ -489,7 +489,6 @@ io_restore:
lg %r14,__LC_VDSO_PER_CPU
lmg %r0,%r10,__PT_R0(%r11)
mvc __LC_RETURN_PSW(16),__PT_PSW(%r11)
ni __LC_RETURN_PSW+1,0xfd # clear wait state bit
stpt __LC_EXIT_TIMER
mvc __VDSO_ECTG_BASE(16,%r14),__LC_EXIT_TIMER
lmg %r11,%r15,__PT_R11(%r11)
......@@ -631,6 +630,24 @@ ext_skip:
brasl %r14,do_extint
j io_return
/*
* Load idle PSW. The second "half" of this function is in cleanup_idle.
*/
ENTRY(psw_idle)
stg %r4,__SF_EMPTY(%r15)
larl %r1,psw_idle_lpsw+4
stg %r1,__SF_EMPTY+8(%r15)
larl %r1,.Lvtimer_max
stck __IDLE_ENTER(%r2)
ltr %r5,%r5
stpt __VQ_IDLE_ENTER(%r3)
jz psw_idle_lpsw
spt 0(%r1)
psw_idle_lpsw:
lpswe __SF_EMPTY(%r15)
br %r14
psw_idle_end:
__critical_end:
/*
......@@ -696,7 +713,6 @@ mcck_return:
lg %r14,__LC_VDSO_PER_CPU
lmg %r0,%r10,__PT_R0(%r11)
mvc __LC_RETURN_MCCK_PSW(16),__PT_PSW(%r11) # move return PSW
ni __LC_RETURN_MCCK_PSW+1,0xfd # clear wait state bit
tm __LC_RETURN_MCCK_PSW+1,0x01 # returning to user ?
jno 0f
stpt __LC_EXIT_TIMER
......@@ -770,6 +786,8 @@ cleanup_table:
.quad io_tif
.quad io_restore
.quad io_done
.quad psw_idle
.quad psw_idle_end
cleanup_critical:
clg %r9,BASED(cleanup_table) # system_call
......@@ -788,6 +806,10 @@ cleanup_critical:
jl cleanup_io_tif
clg %r9,BASED(cleanup_table+56) # io_done
jl cleanup_io_restore
clg %r9,BASED(cleanup_table+64) # psw_idle
jl 0f
clg %r9,BASED(cleanup_table+72) # psw_idle_end
jl cleanup_idle
0: br %r14
......@@ -877,7 +899,6 @@ cleanup_io_restore:
je 0f
lg %r9,24(%r11) # get saved r11 pointer to pt_regs
mvc __LC_RETURN_PSW(16),__PT_PSW(%r9)
ni __LC_RETURN_PSW+1,0xfd # clear wait state bit
mvc 0(64,%r11),__PT_R8(%r9)
lmg %r0,%r7,__PT_R0(%r9)
0: lmg %r8,%r9,__LC_RETURN_PSW
......@@ -885,6 +906,42 @@ cleanup_io_restore:
cleanup_io_restore_insn:
.quad io_done - 4
cleanup_idle:
# copy interrupt clock & cpu timer
mvc __IDLE_EXIT(8,%r2),__LC_INT_CLOCK
mvc __VQ_IDLE_EXIT(8,%r3),__LC_ASYNC_ENTER_TIMER
cghi %r11,__LC_SAVE_AREA_ASYNC
je 0f
mvc __IDLE_EXIT(8,%r2),__LC_MCCK_CLOCK
mvc __VQ_IDLE_EXIT(8,%r3),__LC_MCCK_ENTER_TIMER
0: # check if stck & stpt have been executed
clg %r9,BASED(cleanup_idle_insn)
jhe 1f
mvc __IDLE_ENTER(8,%r2),__IDLE_EXIT(%r2)
mvc __VQ_IDLE_ENTER(8,%r3),__VQ_IDLE_EXIT(%r3)
j 2f
1: # check if the cpu timer has been reprogrammed
ltr %r5,%r5
jz 2f
spt __VQ_IDLE_ENTER(%r3)
2: # account system time going idle
lg %r9,__LC_STEAL_TIMER
alg %r9,__IDLE_ENTER(%r2)
slg %r9,__LC_LAST_UPDATE_CLOCK
stg %r9,__LC_STEAL_TIMER
mvc __LC_LAST_UPDATE_CLOCK(8),__IDLE_EXIT(%r2)
lg %r9,__LC_SYSTEM_TIMER
alg %r9,__LC_LAST_UPDATE_TIMER
slg %r9,__VQ_IDLE_ENTER(%r3)
stg %r9,__LC_SYSTEM_TIMER
mvc __LC_LAST_UPDATE_TIMER(8),__VQ_IDLE_EXIT(%r3)
# prepare return psw
nihh %r8,0xfffd # clear wait state bit
lg %r9,48(%r11) # return from psw_idle
br %r14
cleanup_idle_insn:
.quad psw_idle_lpsw
/*
* Integer constants
*/
......@@ -893,6 +950,8 @@ cleanup_io_restore_insn:
.quad __critical_start
.Lcritical_length:
.quad __critical_end - __critical_start
.Lvtimer_max:
.quad 0x7fffffffffffffff
#if defined(CONFIG_KVM) || defined(CONFIG_KVM_MODULE)
......
......@@ -219,8 +219,6 @@ void __irq_entry do_extint(struct pt_regs *regs, unsigned int ext_int_code,
code = (unsigned short) ext_int_code;
old_regs = set_irq_regs(regs);
s390_idle_check(regs, S390_lowcore.int_clock,
S390_lowcore.async_enter_timer);
irq_enter();
if (S390_lowcore.int_clock >= S390_lowcore.clock_comparator)
/* Serve timer interrupts first. */
......
......@@ -254,8 +254,6 @@ void notrace s390_do_machine_check(struct pt_regs *regs)
int umode;
nmi_enter();
s390_idle_check(regs, S390_lowcore.mcck_clock,
S390_lowcore.mcck_enter_timer);
kstat_cpu(smp_processor_id()).irqs[NMI_NMI]++;
mci = (struct mci *) &S390_lowcore.mcck_interruption_code;
mcck = &__get_cpu_var(cpu_mcck);
......
......@@ -77,13 +77,8 @@ static void default_idle(void)
local_irq_enable();
return;
}
trace_hardirqs_on();
/* Don't trace preempt off for idle. */
stop_critical_timings();
/* Stop virtual timer and halt the cpu. */
/* Halt the cpu and keep track of cpu time accounting. */
vtime_stop_cpu();
/* Reenable preemption tracer. */
start_critical_timings();
}
void cpu_idle(void)
......
......@@ -972,22 +972,16 @@ static DEVICE_ATTR(capability, 0444, show_capability, NULL);
static ssize_t show_idle_count(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct s390_idle_data *idle;
struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id);
unsigned long long idle_count;
unsigned int sequence;
idle = &per_cpu(s390_idle, dev->id);
repeat:
sequence = idle->sequence;
smp_rmb();
if (sequence & 1)
goto repeat;
idle_count = idle->idle_count;
if (idle->idle_enter)
idle_count++;
smp_rmb();
if (idle->sequence != sequence)
goto repeat;
do {
sequence = ACCESS_ONCE(idle->sequence);
idle_count = ACCESS_ONCE(idle->idle_count);
if (ACCESS_ONCE(idle->idle_enter))
idle_count++;
} while ((sequence & 1) || (idle->sequence != sequence));
return sprintf(buf, "%llu\n", idle_count);
}
static DEVICE_ATTR(idle_count, 0444, show_idle_count, NULL);
......@@ -995,24 +989,18 @@ static DEVICE_ATTR(idle_count, 0444, show_idle_count, NULL);
static ssize_t show_idle_time(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct s390_idle_data *idle;
unsigned long long now, idle_time, idle_enter;
struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id);
unsigned long long now, idle_time, idle_enter, idle_exit;
unsigned int sequence;
idle = &per_cpu(s390_idle, dev->id);
now = get_clock();
repeat:
sequence = idle->sequence;
smp_rmb();
if (sequence & 1)
goto repeat;
idle_time = idle->idle_time;
idle_enter = idle->idle_enter;
if (idle_enter != 0ULL && idle_enter < now)
idle_time += now - idle_enter;
smp_rmb();
if (idle->sequence != sequence)
goto repeat;
do {
now = get_clock();
sequence = ACCESS_ONCE(idle->sequence);
idle_time = ACCESS_ONCE(idle->idle_time);
idle_enter = ACCESS_ONCE(idle->idle_enter);
idle_exit = ACCESS_ONCE(idle->idle_exit);
} while ((sequence & 1) || (idle->sequence != sequence));
idle_time += idle_enter ? ((idle_exit ? : now) - idle_enter) : 0;
return sprintf(buf, "%llu\n", idle_time >> 12);
}
static DEVICE_ATTR(idle_time_us, 0444, show_idle_time, NULL);
......
......@@ -26,6 +26,7 @@
#include <asm/irq_regs.h>
#include <asm/cputime.h>
#include <asm/irq.h>
#include "entry.h"
static DEFINE_PER_CPU(struct vtimer_queue, virt_cpu_timer);
......@@ -123,153 +124,53 @@ void account_system_vtime(struct task_struct *tsk)
}
EXPORT_SYMBOL_GPL(account_system_vtime);
void __kprobes vtime_start_cpu(__u64 int_clock, __u64 enter_timer)
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);
__u64 idle_time, expires;
unsigned long long idle_time;
unsigned long psw_mask;
if (idle->idle_enter == 0ULL)
return;
trace_hardirqs_on();
/* Don't trace preempt off for idle. */
stop_critical_timings();
/* Account time spent with enabled wait psw loaded as idle time. */
idle_time = int_clock - idle->idle_enter;
account_idle_time(idle_time);
S390_lowcore.steal_timer +=
idle->idle_enter - S390_lowcore.last_update_clock;
S390_lowcore.last_update_clock = int_clock;
/* Account system time spent going idle. */
S390_lowcore.system_timer += S390_lowcore.last_update_timer - vq->idle;
S390_lowcore.last_update_timer = enter_timer;
/* Restart vtime CPU timer */
if (vq->do_spt) {
/* Program old expire value but first save progress. */
expires = vq->idle - enter_timer;
expires += get_vtimer();
set_vtimer(expires);
} else {
/* Don't account the CPU timer delta while the cpu was idle. */
vq->elapsed -= vq->idle - enter_timer;
}
/* Wait for external, I/O or machine check interrupt. */
psw_mask = psw_kernel_bits | PSW_MASK_WAIT | PSW_MASK_DAT |
PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
idle->nohz_delay = 0;
/* Call the assembler magic in entry.S */
psw_idle(idle, vq, psw_mask, !list_empty(&vq->list));
/* Reenable preemption tracer. */
start_critical_timings();
/* Account time spent with enabled wait psw loaded as idle time. */
idle->sequence++;
smp_wmb();
idle_time = idle->idle_exit - idle->idle_enter;
idle->idle_time += idle_time;
idle->idle_enter = 0ULL;
idle->idle_enter = idle->idle_exit = 0ULL;
idle->idle_count++;
account_idle_time(idle_time);
smp_wmb();
idle->sequence++;
}
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);
psw_t psw;
/* Wait for external, I/O or machine check interrupt. */
psw.mask = psw_kernel_bits | PSW_MASK_WAIT |
PSW_MASK_DAT | PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
idle->nohz_delay = 0;
/* Check if the CPU timer needs to be reprogrammed. */
if (vq->do_spt) {
__u64 vmax = VTIMER_MAX_SLICE;
/*
* The inline assembly is equivalent to
* vq->idle = get_cpu_timer();
* set_cpu_timer(VTIMER_MAX_SLICE);
* idle->idle_enter = get_clock();
* __load_psw_mask(psw_kernel_bits | PSW_MASK_WAIT |
* PSW_MASK_DAT | PSW_MASK_IO |
* PSW_MASK_EXT | PSW_MASK_MCHECK);
* The difference is that the inline assembly makes sure that
* the last three instruction are stpt, stck and lpsw in that
* order. This is done to increase the precision.
*/
asm volatile(
#ifndef CONFIG_64BIT
" basr 1,0\n"
"0: ahi 1,1f-0b\n"
" st 1,4(%2)\n"
#else /* CONFIG_64BIT */
" larl 1,1f\n"
" stg 1,8(%2)\n"
#endif /* CONFIG_64BIT */
" stpt 0(%4)\n"
" spt 0(%5)\n"
" stck 0(%3)\n"
#ifndef CONFIG_64BIT
" lpsw 0(%2)\n"
#else /* CONFIG_64BIT */
" lpswe 0(%2)\n"
#endif /* CONFIG_64BIT */
"1:"
: "=m" (idle->idle_enter), "=m" (vq->idle)
: "a" (&psw), "a" (&idle->idle_enter),
"a" (&vq->idle), "a" (&vmax), "m" (vmax), "m" (psw)
: "memory", "cc", "1");
} else {
/*
* The inline assembly is equivalent to
* vq->idle = get_cpu_timer();
* idle->idle_enter = get_clock();
* __load_psw_mask(psw_kernel_bits | PSW_MASK_WAIT |
* PSW_MASK_DAT | PSW_MASK_IO |
* PSW_MASK_EXT | PSW_MASK_MCHECK);
* The difference is that the inline assembly makes sure that
* the last three instruction are stpt, stck and lpsw in that
* order. This is done to increase the precision.
*/
asm volatile(
#ifndef CONFIG_64BIT
" basr 1,0\n"
"0: ahi 1,1f-0b\n"
" st 1,4(%2)\n"
#else /* CONFIG_64BIT */
" larl 1,1f\n"
" stg 1,8(%2)\n"
#endif /* CONFIG_64BIT */
" stpt 0(%4)\n"
" stck 0(%3)\n"
#ifndef CONFIG_64BIT
" lpsw 0(%2)\n"
#else /* CONFIG_64BIT */
" lpswe 0(%2)\n"
#endif /* CONFIG_64BIT */
"1:"
: "=m" (idle->idle_enter), "=m" (vq->idle)
: "a" (&psw), "a" (&idle->idle_enter),
"a" (&vq->idle), "m" (psw)
: "memory", "cc", "1");
}
}
cputime64_t s390_get_idle_time(int cpu)
{
struct s390_idle_data *idle;
unsigned long long now, idle_time, idle_enter;
struct s390_idle_data *idle = &per_cpu(s390_idle, cpu);
unsigned long long now, idle_enter, idle_exit;
unsigned int sequence;
idle = &per_cpu(s390_idle, cpu);
now = get_clock();
repeat:
sequence = idle->sequence;
smp_rmb();
if (sequence & 1)
goto repeat;
idle_time = 0;
idle_enter = idle->idle_enter;
if (idle_enter != 0ULL && idle_enter < now)
idle_time = now - idle_enter;
smp_rmb();
if (idle->sequence != sequence)
goto repeat;
return idle_time;
do {
now = get_clock();
sequence = ACCESS_ONCE(idle->sequence);
idle_enter = ACCESS_ONCE(idle->idle_enter);
idle_exit = ACCESS_ONCE(idle->idle_exit);
} while ((sequence & 1) || (idle->sequence != sequence));
return idle_enter ? ((idle_exit ? : now) - idle_enter) : 0;
}
/*
......@@ -346,7 +247,6 @@ static void do_cpu_timer_interrupt(unsigned int ext_int_code,
}
spin_unlock(&vq->lock);
vq->do_spt = list_empty(&cb_list);
do_callbacks(&cb_list);
/* next event is first in list */
......@@ -355,8 +255,7 @@ static void do_cpu_timer_interrupt(unsigned int ext_int_code,
if (!list_empty(&vq->list)) {
event = list_first_entry(&vq->list, struct vtimer_list, entry);
next = event->expires;
} else
vq->do_spt = 0;
}
spin_unlock(&vq->lock);
/*