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Merge branch 'x86/paravirt-spinlocks' into x86/for-linus

This commit is contained in:
Ingo Molnar 2008-07-21 16:45:56 +02:00
parent acee709cab 1c29dd9a9e
commit 2e2dcc7631
9 changed files with 379 additions and 17 deletions
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3
arch/x86/kernel/Makefile
View File

@ -7,9 +7,10 @@ extra-y := head_$(BITS).o head$(BITS).o head.o init_task.o vmlinu
CPPFLAGS_vmlinux.lds += -U$(UTS_MACHINE)
ifdef CONFIG_FTRACE
# Do not profile debug utilities
# Do not profile debug and lowlevel utilities
CFLAGS_REMOVE_tsc.o = -pg
CFLAGS_REMOVE_rtc.o = -pg
CFLAGS_REMOVE_paravirt.o = -pg
endif
#

24
arch/x86/kernel/paravirt.c
View File

@ -124,6 +124,7 @@ static void *get_call_destination(u8 type)
.pv_irq_ops = pv_irq_ops,
.pv_apic_ops = pv_apic_ops,
.pv_mmu_ops = pv_mmu_ops,
.pv_lock_ops = pv_lock_ops,
};
return *((void **)&tmpl + type);
}
@ -267,6 +268,17 @@ enum paravirt_lazy_mode paravirt_get_lazy_mode(void)
return __get_cpu_var(paravirt_lazy_mode);
}
void __init paravirt_use_bytelocks(void)
{
#ifdef CONFIG_SMP
pv_lock_ops.spin_is_locked = __byte_spin_is_locked;
pv_lock_ops.spin_is_contended = __byte_spin_is_contended;
pv_lock_ops.spin_lock = __byte_spin_lock;
pv_lock_ops.spin_trylock = __byte_spin_trylock;
pv_lock_ops.spin_unlock = __byte_spin_unlock;
#endif
}
struct pv_info pv_info = {
.name = "bare hardware",
.paravirt_enabled = 0,
@ -449,6 +461,18 @@ struct pv_mmu_ops pv_mmu_ops = {
.set_fixmap = native_set_fixmap,
};
struct pv_lock_ops pv_lock_ops = {
#ifdef CONFIG_SMP
.spin_is_locked = __ticket_spin_is_locked,
.spin_is_contended = __ticket_spin_is_contended,
.spin_lock = __ticket_spin_lock,
.spin_trylock = __ticket_spin_trylock,
.spin_unlock = __ticket_spin_unlock,
#endif
};
EXPORT_SYMBOL_GPL(pv_lock_ops);
EXPORT_SYMBOL_GPL(pv_time_ops);
EXPORT_SYMBOL (pv_cpu_ops);
EXPORT_SYMBOL (pv_mmu_ops);

171
arch/x86/xen/smp.c
View File

@ -15,6 +15,7 @@
* This does not handle HOTPLUG_CPU yet.
*/
#include <linux/sched.h>
#include <linux/kernel_stat.h>
#include <linux/err.h>
#include <linux/smp.h>
@ -35,6 +36,8 @@
#include "xen-ops.h"
#include "mmu.h"
static void __cpuinit xen_init_lock_cpu(int cpu);
cpumask_t xen_cpu_initialized_map;
static DEFINE_PER_CPU(int, resched_irq);
@ -179,6 +182,8 @@ static void __init xen_smp_prepare_cpus(unsigned int max_cpus)
{
unsigned cpu;
xen_init_lock_cpu(0);
smp_store_cpu_info(0);
cpu_data(0).x86_max_cores = 1;
set_cpu_sibling_map(0);
@ -301,6 +306,7 @@ static int __cpuinit xen_cpu_up(unsigned int cpu)
clear_tsk_thread_flag(idle, TIF_FORK);
#endif
xen_setup_timer(cpu);
xen_init_lock_cpu(cpu);
per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
@ -413,6 +419,170 @@ static irqreturn_t xen_call_function_single_interrupt(int irq, void *dev_id)
return IRQ_HANDLED;
}
struct xen_spinlock {
unsigned char lock; /* 0 -> free; 1 -> locked */
unsigned short spinners; /* count of waiting cpus */
};
static int xen_spin_is_locked(struct raw_spinlock *lock)
{
struct xen_spinlock *xl = (struct xen_spinlock *)lock;
return xl->lock != 0;
}
static int xen_spin_is_contended(struct raw_spinlock *lock)
{
struct xen_spinlock *xl = (struct xen_spinlock *)lock;
/* Not strictly true; this is only the count of contended
lock-takers entering the slow path. */
return xl->spinners != 0;
}
static int xen_spin_trylock(struct raw_spinlock *lock)
{
struct xen_spinlock *xl = (struct xen_spinlock *)lock;
u8 old = 1;
asm("xchgb %b0,%1"
: "+q" (old), "+m" (xl->lock) : : "memory");
return old == 0;
}
static DEFINE_PER_CPU(int, lock_kicker_irq) = -1;
static DEFINE_PER_CPU(struct xen_spinlock *, lock_spinners);
static inline void spinning_lock(struct xen_spinlock *xl)
{
__get_cpu_var(lock_spinners) = xl;
wmb(); /* set lock of interest before count */
asm(LOCK_PREFIX " incw %0"
: "+m" (xl->spinners) : : "memory");
}
static inline void unspinning_lock(struct xen_spinlock *xl)
{
asm(LOCK_PREFIX " decw %0"
: "+m" (xl->spinners) : : "memory");
wmb(); /* decrement count before clearing lock */
__get_cpu_var(lock_spinners) = NULL;
}
static noinline int xen_spin_lock_slow(struct raw_spinlock *lock)
{
struct xen_spinlock *xl = (struct xen_spinlock *)lock;
int irq = __get_cpu_var(lock_kicker_irq);
int ret;
/* If kicker interrupts not initialized yet, just spin */
if (irq == -1)
return 0;
/* announce we're spinning */
spinning_lock(xl);
/* clear pending */
xen_clear_irq_pending(irq);
/* check again make sure it didn't become free while
we weren't looking */
ret = xen_spin_trylock(lock);
if (ret)
goto out;
/* block until irq becomes pending */
xen_poll_irq(irq);
kstat_this_cpu.irqs[irq]++;
out:
unspinning_lock(xl);
return ret;
}
static void xen_spin_lock(struct raw_spinlock *lock)
{
struct xen_spinlock *xl = (struct xen_spinlock *)lock;
int timeout;
u8 oldval;
do {
timeout = 1 << 10;
asm("1: xchgb %1,%0\n"
" testb %1,%1\n"
" jz 3f\n"
"2: rep;nop\n"
" cmpb $0,%0\n"
" je 1b\n"
" dec %2\n"
" jnz 2b\n"
"3:\n"
: "+m" (xl->lock), "=q" (oldval), "+r" (timeout)
: "1" (1)
: "memory");
} while (unlikely(oldval != 0 && !xen_spin_lock_slow(lock)));
}
static noinline void xen_spin_unlock_slow(struct xen_spinlock *xl)
{
int cpu;
for_each_online_cpu(cpu) {
/* XXX should mix up next cpu selection */
if (per_cpu(lock_spinners, cpu) == xl) {
xen_send_IPI_one(cpu, XEN_SPIN_UNLOCK_VECTOR);
break;
}
}
}
static void xen_spin_unlock(struct raw_spinlock *lock)
{
struct xen_spinlock *xl = (struct xen_spinlock *)lock;
smp_wmb(); /* make sure no writes get moved after unlock */
xl->lock = 0; /* release lock */
/* make sure unlock happens before kick */
barrier();
if (unlikely(xl->spinners))
xen_spin_unlock_slow(xl);
}
static __cpuinit void xen_init_lock_cpu(int cpu)
{
int irq;
const char *name;
name = kasprintf(GFP_KERNEL, "spinlock%d", cpu);
irq = bind_ipi_to_irqhandler(XEN_SPIN_UNLOCK_VECTOR,
cpu,
xen_reschedule_interrupt,
IRQF_DISABLED|IRQF_PERCPU|IRQF_NOBALANCING,
name,
NULL);
if (irq >= 0) {
disable_irq(irq); /* make sure it's never delivered */
per_cpu(lock_kicker_irq, cpu) = irq;
}
printk("cpu %d spinlock event irq %d\n", cpu, irq);
}
static void __init xen_init_spinlocks(void)
{
pv_lock_ops.spin_is_locked = xen_spin_is_locked;
pv_lock_ops.spin_is_contended = xen_spin_is_contended;
pv_lock_ops.spin_lock = xen_spin_lock;
pv_lock_ops.spin_trylock = xen_spin_trylock;
pv_lock_ops.spin_unlock = xen_spin_unlock;
}
static const struct smp_ops xen_smp_ops __initdata = {
.smp_prepare_boot_cpu = xen_smp_prepare_boot_cpu,
.smp_prepare_cpus = xen_smp_prepare_cpus,
@ -430,4 +600,5 @@ void __init xen_smp_init(void)
{
smp_ops = xen_smp_ops;
xen_fill_possible_map();
xen_init_spinlocks();
}

27
drivers/xen/events.c
View File

@ -734,6 +734,33 @@ static void restore_cpu_ipis(unsigned int cpu)
}
}
/* Clear an irq's pending state, in preparation for polling on it */
void xen_clear_irq_pending(int irq)
{
int evtchn = evtchn_from_irq(irq);
if (VALID_EVTCHN(evtchn))
clear_evtchn(evtchn);
}
/* Poll waiting for an irq to become pending. In the usual case, the
irq will be disabled so it won't deliver an interrupt. */
void xen_poll_irq(int irq)
{
evtchn_port_t evtchn = evtchn_from_irq(irq);
if (VALID_EVTCHN(evtchn)) {
struct sched_poll poll;
poll.nr_ports = 1;
poll.timeout = 0;
poll.ports = &evtchn;
if (HYPERVISOR_sched_op(SCHEDOP_poll, &poll) != 0)
BUG();
}
}
void xen_irq_resume(void)
{
unsigned int cpu, irq, evtchn;

43
include/asm-x86/paravirt.h
View File

@ -325,6 +325,15 @@ struct pv_mmu_ops {
unsigned long phys, pgprot_t flags);
};
struct raw_spinlock;
struct pv_lock_ops {
int (*spin_is_locked)(struct raw_spinlock *lock);
int (*spin_is_contended)(struct raw_spinlock *lock);
void (*spin_lock)(struct raw_spinlock *lock);
int (*spin_trylock)(struct raw_spinlock *lock);
void (*spin_unlock)(struct raw_spinlock *lock);
};
/* This contains all the paravirt structures: we get a convenient
* number for each function using the offset which we use to indicate
* what to patch. */
@ -335,6 +344,7 @@ struct paravirt_patch_template {
struct pv_irq_ops pv_irq_ops;
struct pv_apic_ops pv_apic_ops;
struct pv_mmu_ops pv_mmu_ops;
struct pv_lock_ops pv_lock_ops;
};
extern struct pv_info pv_info;
@ -344,6 +354,7 @@ extern struct pv_cpu_ops pv_cpu_ops;
extern struct pv_irq_ops pv_irq_ops;
extern struct pv_apic_ops pv_apic_ops;
extern struct pv_mmu_ops pv_mmu_ops;
extern struct pv_lock_ops pv_lock_ops;
#define PARAVIRT_PATCH(x) \
(offsetof(struct paravirt_patch_template, x) / sizeof(void *))
@ -1368,6 +1379,37 @@ static inline void __set_fixmap(unsigned /* enum fixed_addresses */ idx,
void _paravirt_nop(void);
#define paravirt_nop ((void *)_paravirt_nop)
void paravirt_use_bytelocks(void);
#ifdef CONFIG_SMP
static inline int __raw_spin_is_locked(struct raw_spinlock *lock)
{
return PVOP_CALL1(int, pv_lock_ops.spin_is_locked, lock);
}
static inline int __raw_spin_is_contended(struct raw_spinlock *lock)
{
return PVOP_CALL1(int, pv_lock_ops.spin_is_contended, lock);
}
static __always_inline void __raw_spin_lock(struct raw_spinlock *lock)
{
PVOP_VCALL1(pv_lock_ops.spin_lock, lock);
}
static __always_inline int __raw_spin_trylock(struct raw_spinlock *lock)
{
return PVOP_CALL1(int, pv_lock_ops.spin_trylock, lock);
}
static __always_inline void __raw_spin_unlock(struct raw_spinlock *lock)
{
PVOP_VCALL1(pv_lock_ops.spin_unlock, lock);
}
#endif
/* These all sit in the .parainstructions section to tell us what to patch. */
struct paravirt_patch_site {
u8 *instr; /* original instructions */
@ -1452,6 +1494,7 @@ static inline unsigned long __raw_local_irq_save(void)
return f;
}
/* Make sure as little as possible of this mess escapes. */
#undef PARAVIRT_CALL
#undef __PVOP_CALL

118
include/asm-x86/spinlock.h
View File

@ -6,7 +6,7 @@
#include <asm/page.h>
#include <asm/processor.h>
#include <linux/compiler.h>
#include <asm/paravirt.h>
/*
* Your basic SMP spinlocks, allowing only a single CPU anywhere
*
@ -54,21 +54,21 @@
* much between them in performance though, especially as locks are out of line.
*/
#if (NR_CPUS < 256)
static inline int __raw_spin_is_locked(raw_spinlock_t *lock)
static inline int __ticket_spin_is_locked(raw_spinlock_t *lock)
{
int tmp = ACCESS_ONCE(lock->slock);
return (((tmp >> 8) & 0xff) != (tmp & 0xff));
}
static inline int __raw_spin_is_contended(raw_spinlock_t *lock)
static inline int __ticket_spin_is_contended(raw_spinlock_t *lock)
{
int tmp = ACCESS_ONCE(lock->slock);
return (((tmp >> 8) & 0xff) - (tmp & 0xff)) > 1;
}
static __always_inline void __raw_spin_lock(raw_spinlock_t *lock)
static __always_inline void __ticket_spin_lock(raw_spinlock_t *lock)
{
short inc = 0x0100;
@ -87,9 +87,7 @@ static __always_inline void __raw_spin_lock(raw_spinlock_t *lock)
: "memory", "cc");
}
#define __raw_spin_lock_flags(lock, flags) __raw_spin_lock(lock)
static __always_inline int __raw_spin_trylock(raw_spinlock_t *lock)
static __always_inline int __ticket_spin_trylock(raw_spinlock_t *lock)
{
int tmp;
short new;
@ -110,7 +108,7 @@ static __always_inline int __raw_spin_trylock(raw_spinlock_t *lock)
return tmp;
}
static __always_inline void __raw_spin_unlock(raw_spinlock_t *lock)
static __always_inline void __ticket_spin_unlock(raw_spinlock_t *lock)
{
asm volatile(UNLOCK_LOCK_PREFIX "incb %0"
: "+m" (lock->slock)
@ -118,21 +116,21 @@ static __always_inline void __raw_spin_unlock(raw_spinlock_t *lock)
: "memory", "cc");
}
#else
static inline int __raw_spin_is_locked(raw_spinlock_t *lock)
static inline int __ticket_spin_is_locked(raw_spinlock_t *lock)
{
int tmp = ACCESS_ONCE(lock->slock);
return (((tmp >> 16) & 0xffff) != (tmp & 0xffff));
}
static inline int __raw_spin_is_contended(raw_spinlock_t *lock)
static inline int __ticket_spin_is_contended(raw_spinlock_t *lock)
{
int tmp = ACCESS_ONCE(lock->slock);
return (((tmp >> 16) & 0xffff) - (tmp & 0xffff)) > 1;
}
static __always_inline void __raw_spin_lock(raw_spinlock_t *lock)
static __always_inline void __ticket_spin_lock(raw_spinlock_t *lock)
{
int inc = 0x00010000;
int tmp;
@ -153,9 +151,7 @@ static __always_inline void __raw_spin_lock(raw_spinlock_t *lock)
: "memory", "cc");
}
#define __raw_spin_lock_flags(lock, flags) __raw_spin_lock(lock)
static __always_inline int __raw_spin_trylock(raw_spinlock_t *lock)
static __always_inline int __ticket_spin_trylock(raw_spinlock_t *lock)
{
int tmp;
int new;
@ -177,7 +173,7 @@ static __always_inline int __raw_spin_trylock(raw_spinlock_t *lock)
return tmp;
}
static __always_inline void __raw_spin_unlock(raw_spinlock_t *lock)
static __always_inline void __ticket_spin_unlock(raw_spinlock_t *lock)
{
asm volatile(UNLOCK_LOCK_PREFIX "incw %0"
: "+m" (lock->slock)
@ -186,6 +182,98 @@ static __always_inline void __raw_spin_unlock(raw_spinlock_t *lock)
}
#endif
#define __raw_spin_lock_flags(lock, flags) __raw_spin_lock(lock)
#ifdef CONFIG_PARAVIRT
/*
* Define virtualization-friendly old-style lock byte lock, for use in
* pv_lock_ops if desired.
*
* This differs from the pre-2.6.24 spinlock by always using xchgb
* rather than decb to take the lock; this allows it to use a
* zero-initialized lock structure. It also maintains a 1-byte
* contention counter, so that we can implement
* __byte_spin_is_contended.
*/
struct __byte_spinlock {
s8 lock;
s8 spinners;
};
static inline int __byte_spin_is_locked(raw_spinlock_t *lock)
{
struct __byte_spinlock *bl = (struct __byte_spinlock *)lock;
return bl->lock != 0;
}
static inline int __byte_spin_is_contended(raw_spinlock_t *lock)
{
struct __byte_spinlock *bl = (struct __byte_spinlock *)lock;
return bl->spinners != 0;
}
static inline void __byte_spin_lock(raw_spinlock_t *lock)
{
struct __byte_spinlock *bl = (struct __byte_spinlock *)lock;
s8 val = 1;
asm("1: xchgb %1, %0\n"
" test %1,%1\n"
" jz 3f\n"
" " LOCK_PREFIX "incb %2\n"
"2: rep;nop\n"
" cmpb $1, %0\n"
" je 2b\n"
" " LOCK_PREFIX "decb %2\n"
" jmp 1b\n"
"3:"
: "+m" (bl->lock), "+q" (val), "+m" (bl->spinners): : "memory");
}
static inline int __byte_spin_trylock(raw_spinlock_t *lock)
{
struct __byte_spinlock *bl = (struct __byte_spinlock *)lock;
u8 old = 1;
asm("xchgb %1,%0"
: "+m" (bl->lock), "+q" (old) : : "memory");
return old == 0;
}
static inline void __byte_spin_unlock(raw_spinlock_t *lock)
{
struct __byte_spinlock *bl = (struct __byte_spinlock *)lock;
smp_wmb();
bl->lock = 0;
}
#else /* !CONFIG_PARAVIRT */
static inline int __raw_spin_is_locked(raw_spinlock_t *lock)
{
return __ticket_spin_is_locked(lock);
}
static inline int __raw_spin_is_contended(raw_spinlock_t *lock)
{
return __ticket_spin_is_contended(lock);
}
static __always_inline void __raw_spin_lock(raw_spinlock_t *lock)
{
__ticket_spin_lock(lock);
}
static __always_inline int __raw_spin_trylock(raw_spinlock_t *lock)
{
return __ticket_spin_trylock(lock);
}
static __always_inline void __raw_spin_unlock(raw_spinlock_t *lock)
{
__ticket_spin_unlock(lock);
}
#endif /* CONFIG_PARAVIRT */
static inline void __raw_spin_unlock_wait(raw_spinlock_t *lock)
{
while (__raw_spin_is_locked(lock))

2
include/asm-x86/spinlock_types.h
View File

@ -5,7 +5,7 @@
# error "please don't include this file directly"
#endif
typedef struct {
typedef struct raw_spinlock {
unsigned int slock;
} raw_spinlock_t;

1
include/asm-x86/xen/events.h
View File

@ -5,6 +5,7 @@ enum ipi_vector {
XEN_RESCHEDULE_VECTOR,
XEN_CALL_FUNCTION_VECTOR,
XEN_CALL_FUNCTION_SINGLE_VECTOR,
XEN_SPIN_UNLOCK_VECTOR,
XEN_NR_IPIS,
};

7
include/xen/events.h
View File

@ -44,4 +44,11 @@ extern void notify_remote_via_irq(int irq);
extern void xen_irq_resume(void);
/* Clear an irq's pending state, in preparation for polling on it */
void xen_clear_irq_pending(int irq);
/* Poll waiting for an irq to become pending. In the usual case, the
irq will be disabled so it won't deliver an interrupt. */
void xen_poll_irq(int irq);
#endif /* _XEN_EVENTS_H */