forked from Minki/linux
3c1fcfe229
Use the new diagnose 0x9c in the spinlock implementation for s390. It yields the remaining timeslice of the virtual cpu that tries to acquire a lock to the virtual cpu that is the current holder of the lock. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
154 lines
3.0 KiB
C
154 lines
3.0 KiB
C
/*
|
|
* arch/s390/lib/spinlock.c
|
|
* Out of line spinlock code.
|
|
*
|
|
* Copyright (C) IBM Corp. 2004, 2006
|
|
* Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
|
|
*/
|
|
|
|
#include <linux/types.h>
|
|
#include <linux/module.h>
|
|
#include <linux/spinlock.h>
|
|
#include <linux/init.h>
|
|
#include <asm/io.h>
|
|
|
|
int spin_retry = 1000;
|
|
|
|
/**
|
|
* spin_retry= parameter
|
|
*/
|
|
static int __init spin_retry_setup(char *str)
|
|
{
|
|
spin_retry = simple_strtoul(str, &str, 0);
|
|
return 1;
|
|
}
|
|
__setup("spin_retry=", spin_retry_setup);
|
|
|
|
static inline void _raw_yield(void)
|
|
{
|
|
if (MACHINE_HAS_DIAG44)
|
|
asm volatile("diag 0,0,0x44");
|
|
}
|
|
|
|
static inline void _raw_yield_cpu(int cpu)
|
|
{
|
|
if (MACHINE_HAS_DIAG9C)
|
|
asm volatile("diag %0,0,0x9c"
|
|
: : "d" (__cpu_logical_map[cpu]));
|
|
else
|
|
_raw_yield();
|
|
}
|
|
|
|
void _raw_spin_lock_wait(raw_spinlock_t *lp, unsigned int pc)
|
|
{
|
|
int count = spin_retry;
|
|
unsigned int cpu = ~smp_processor_id();
|
|
|
|
while (1) {
|
|
if (count-- <= 0) {
|
|
unsigned int owner = lp->owner_cpu;
|
|
if (owner != 0)
|
|
_raw_yield_cpu(~owner);
|
|
count = spin_retry;
|
|
}
|
|
if (__raw_spin_is_locked(lp))
|
|
continue;
|
|
if (_raw_compare_and_swap(&lp->owner_cpu, 0, cpu) == 0) {
|
|
lp->owner_pc = pc;
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(_raw_spin_lock_wait);
|
|
|
|
int _raw_spin_trylock_retry(raw_spinlock_t *lp, unsigned int pc)
|
|
{
|
|
unsigned int cpu = ~smp_processor_id();
|
|
int count;
|
|
|
|
for (count = spin_retry; count > 0; count--) {
|
|
if (__raw_spin_is_locked(lp))
|
|
continue;
|
|
if (_raw_compare_and_swap(&lp->owner_cpu, 0, cpu) == 0) {
|
|
lp->owner_pc = pc;
|
|
return 1;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(_raw_spin_trylock_retry);
|
|
|
|
void _raw_spin_relax(raw_spinlock_t *lock)
|
|
{
|
|
unsigned int cpu = lock->owner_cpu;
|
|
if (cpu != 0)
|
|
_raw_yield_cpu(~cpu);
|
|
}
|
|
EXPORT_SYMBOL(_raw_spin_relax);
|
|
|
|
void _raw_read_lock_wait(raw_rwlock_t *rw)
|
|
{
|
|
unsigned int old;
|
|
int count = spin_retry;
|
|
|
|
while (1) {
|
|
if (count-- <= 0) {
|
|
_raw_yield();
|
|
count = spin_retry;
|
|
}
|
|
if (!__raw_read_can_lock(rw))
|
|
continue;
|
|
old = rw->lock & 0x7fffffffU;
|
|
if (_raw_compare_and_swap(&rw->lock, old, old + 1) == old)
|
|
return;
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(_raw_read_lock_wait);
|
|
|
|
int _raw_read_trylock_retry(raw_rwlock_t *rw)
|
|
{
|
|
unsigned int old;
|
|
int count = spin_retry;
|
|
|
|
while (count-- > 0) {
|
|
if (!__raw_read_can_lock(rw))
|
|
continue;
|
|
old = rw->lock & 0x7fffffffU;
|
|
if (_raw_compare_and_swap(&rw->lock, old, old + 1) == old)
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(_raw_read_trylock_retry);
|
|
|
|
void _raw_write_lock_wait(raw_rwlock_t *rw)
|
|
{
|
|
int count = spin_retry;
|
|
|
|
while (1) {
|
|
if (count-- <= 0) {
|
|
_raw_yield();
|
|
count = spin_retry;
|
|
}
|
|
if (!__raw_write_can_lock(rw))
|
|
continue;
|
|
if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0)
|
|
return;
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(_raw_write_lock_wait);
|
|
|
|
int _raw_write_trylock_retry(raw_rwlock_t *rw)
|
|
{
|
|
int count = spin_retry;
|
|
|
|
while (count-- > 0) {
|
|
if (!__raw_write_can_lock(rw))
|
|
continue;
|
|
if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0)
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(_raw_write_trylock_retry);
|