diff options
| -rw-r--r-- | arch/x86/include/asm/paravirt.h | 32 | ||||
| -rw-r--r-- | arch/x86/include/asm/paravirt_types.h | 14 | ||||
| -rw-r--r-- | arch/x86/include/asm/spinlock.h | 53 | ||||
| -rw-r--r-- | arch/x86/include/asm/spinlock_types.h | 4 | ||||
| -rw-r--r-- | arch/x86/kernel/paravirt-spinlocks.c | 15 | ||||
| -rw-r--r-- | arch/x86/xen/spinlock.c | 8 |
6 files changed, 65 insertions, 61 deletions
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h index cfdc9ee4c900..040e72db5ea9 100644 --- a/arch/x86/include/asm/paravirt.h +++ b/arch/x86/include/asm/paravirt.h @@ -712,36 +712,16 @@ static inline void __set_fixmap(unsigned /* enum fixed_addresses */ idx, #if defined(CONFIG_SMP) && defined(CONFIG_PARAVIRT_SPINLOCKS) -static inline int arch_spin_is_locked(struct arch_spinlock *lock) +static __always_inline void __ticket_lock_spinning(struct arch_spinlock *lock, + __ticket_t ticket) { - return PVOP_CALL1(int, pv_lock_ops.spin_is_locked, lock); + PVOP_VCALL2(pv_lock_ops.lock_spinning, lock, ticket); } -static inline int arch_spin_is_contended(struct arch_spinlock *lock) +static __always_inline void ____ticket_unlock_kick(struct arch_spinlock *lock, + __ticket_t ticket) { - return PVOP_CALL1(int, pv_lock_ops.spin_is_contended, lock); -} -#define arch_spin_is_contended arch_spin_is_contended - -static __always_inline void arch_spin_lock(struct arch_spinlock *lock) -{ - PVOP_VCALL1(pv_lock_ops.spin_lock, lock); -} - -static __always_inline void arch_spin_lock_flags(struct arch_spinlock *lock, - unsigned long flags) -{ - PVOP_VCALL2(pv_lock_ops.spin_lock_flags, lock, flags); -} - -static __always_inline int arch_spin_trylock(struct arch_spinlock *lock) -{ - return PVOP_CALL1(int, pv_lock_ops.spin_trylock, lock); -} - -static __always_inline void arch_spin_unlock(struct arch_spinlock *lock) -{ - PVOP_VCALL1(pv_lock_ops.spin_unlock, lock); + PVOP_VCALL2(pv_lock_ops.unlock_kick, lock, ticket); } #endif diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h index 0db1fcac668c..346a07c1e71d 100644 --- a/arch/x86/include/asm/paravirt_types.h +++ b/arch/x86/include/asm/paravirt_types.h @@ -327,13 +327,15 @@ struct pv_mmu_ops { }; struct arch_spinlock; +#ifdef CONFIG_SMP +#include <asm/spinlock_types.h> +#else +typedef u16 __ticket_t; +#endif + struct pv_lock_ops { - int (*spin_is_locked)(struct arch_spinlock *lock); - int (*spin_is_contended)(struct arch_spinlock *lock); - void (*spin_lock)(struct arch_spinlock *lock); - void (*spin_lock_flags)(struct arch_spinlock *lock, unsigned long flags); - int (*spin_trylock)(struct arch_spinlock *lock); - void (*spin_unlock)(struct arch_spinlock *lock); + void (*lock_spinning)(struct arch_spinlock *lock, __ticket_t ticket); + void (*unlock_kick)(struct arch_spinlock *lock, __ticket_t ticket); }; /* This contains all the paravirt structures: we get a convenient diff --git a/arch/x86/include/asm/spinlock.h b/arch/x86/include/asm/spinlock.h index 33692eaabab5..4d542444bea3 100644 --- a/arch/x86/include/asm/spinlock.h +++ b/arch/x86/include/asm/spinlock.h @@ -34,6 +34,35 @@ # define UNLOCK_LOCK_PREFIX #endif +/* How long a lock should spin before we consider blocking */ +#define SPIN_THRESHOLD (1 << 15) + +#ifndef CONFIG_PARAVIRT_SPINLOCKS + +static __always_inline void __ticket_lock_spinning(struct arch_spinlock *lock, + __ticket_t ticket) +{ +} + +static __always_inline void ____ticket_unlock_kick(struct arch_spinlock *lock, + __ticket_t ticket) +{ +} + +#endif /* CONFIG_PARAVIRT_SPINLOCKS */ + + +/* + * If a spinlock has someone waiting on it, then kick the appropriate + * waiting cpu. + */ +static __always_inline void __ticket_unlock_kick(struct arch_spinlock *lock, + __ticket_t next) +{ + if (unlikely(lock->tickets.tail != next)) + ____ticket_unlock_kick(lock, next); +} + /* * Ticket locks are conceptually two parts, one indicating the current head of * the queue, and the other indicating the current tail. The lock is acquired @@ -47,19 +76,24 @@ * in the high part, because a wide xadd increment of the low part would carry * up and contaminate the high part. */ -static __always_inline void __ticket_spin_lock(arch_spinlock_t *lock) +static __always_inline void __ticket_spin_lock(struct arch_spinlock *lock) { register struct __raw_tickets inc = { .tail = 1 }; inc = xadd(&lock->tickets, inc); for (;;) { - if (inc.head == inc.tail) - break; - cpu_relax(); - inc.head = ACCESS_ONCE(lock->tickets.head); + unsigned count = SPIN_THRESHOLD; + + do { + if (inc.head == inc.tail) + goto out; + cpu_relax(); + inc.head = ACCESS_ONCE(lock->tickets.head); + } while (--count); + __ticket_lock_spinning(lock, inc.tail); } - barrier(); /* make sure nothing creeps before the lock is taken */ +out: barrier(); /* make sure nothing creeps before the lock is taken */ } static __always_inline int __ticket_spin_trylock(arch_spinlock_t *lock) @@ -78,7 +112,10 @@ static __always_inline int __ticket_spin_trylock(arch_spinlock_t *lock) static __always_inline void __ticket_spin_unlock(arch_spinlock_t *lock) { + __ticket_t next = lock->tickets.head + 1; + __add(&lock->tickets.head, 1, UNLOCK_LOCK_PREFIX); + __ticket_unlock_kick(lock, next); } static inline int __ticket_spin_is_locked(arch_spinlock_t *lock) @@ -95,8 +132,6 @@ static inline int __ticket_spin_is_contended(arch_spinlock_t *lock) return (__ticket_t)(tmp.tail - tmp.head) > 1; } -#ifndef CONFIG_PARAVIRT_SPINLOCKS - static inline int arch_spin_is_locked(arch_spinlock_t *lock) { return __ticket_spin_is_locked(lock); @@ -129,8 +164,6 @@ static __always_inline void arch_spin_lock_flags(arch_spinlock_t *lock, arch_spin_lock(lock); } -#endif /* CONFIG_PARAVIRT_SPINLOCKS */ - static inline void arch_spin_unlock_wait(arch_spinlock_t *lock) { while (arch_spin_is_locked(lock)) diff --git a/arch/x86/include/asm/spinlock_types.h b/arch/x86/include/asm/spinlock_types.h index ad0ad07fc006..83fd3c75d45c 100644 --- a/arch/x86/include/asm/spinlock_types.h +++ b/arch/x86/include/asm/spinlock_types.h @@ -1,10 +1,6 @@ #ifndef _ASM_X86_SPINLOCK_TYPES_H #define _ASM_X86_SPINLOCK_TYPES_H -#ifndef __LINUX_SPINLOCK_TYPES_H -# error "please don't include this file directly" -#endif - #include <linux/types.h> #if (CONFIG_NR_CPUS < 256) diff --git a/arch/x86/kernel/paravirt-spinlocks.c b/arch/x86/kernel/paravirt-spinlocks.c index 676b8c77a976..c2e010e5fbce 100644 --- a/arch/x86/kernel/paravirt-spinlocks.c +++ b/arch/x86/kernel/paravirt-spinlocks.c @@ -7,21 +7,10 @@ #include <asm/paravirt.h> -static inline void -default_spin_lock_flags(arch_spinlock_t *lock, unsigned long flags) -{ - arch_spin_lock(lock); -} - 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_lock_flags = default_spin_lock_flags, - .spin_trylock = __ticket_spin_trylock, - .spin_unlock = __ticket_spin_unlock, + .lock_spinning = paravirt_nop, + .unlock_kick = paravirt_nop, #endif }; EXPORT_SYMBOL(pv_lock_ops); diff --git a/arch/x86/xen/spinlock.c b/arch/x86/xen/spinlock.c index cf3caee356b3..d50962936af4 100644 --- a/arch/x86/xen/spinlock.c +++ b/arch/x86/xen/spinlock.c @@ -139,6 +139,9 @@ struct xen_spinlock { xen_spinners_t spinners; /* count of waiting cpus */ }; +static DEFINE_PER_CPU(int, lock_kicker_irq) = -1; + +#if 0 static int xen_spin_is_locked(struct arch_spinlock *lock) { struct xen_spinlock *xl = (struct xen_spinlock *)lock; @@ -167,7 +170,6 @@ static int xen_spin_trylock(struct arch_spinlock *lock) } static DEFINE_PER_CPU(char *, irq_name); -static DEFINE_PER_CPU(int, lock_kicker_irq) = -1; static DEFINE_PER_CPU(struct xen_spinlock *, lock_spinners); /* @@ -354,6 +356,7 @@ static void xen_spin_unlock(struct arch_spinlock *lock) if (unlikely(xl->spinners)) xen_spin_unlock_slow(xl); } +#endif static irqreturn_t dummy_handler(int irq, void *dev_id) { @@ -418,13 +421,14 @@ void __init xen_init_spinlocks(void) return; BUILD_BUG_ON(sizeof(struct xen_spinlock) > sizeof(arch_spinlock_t)); - +#if 0 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_lock_flags = xen_spin_lock_flags; pv_lock_ops.spin_trylock = xen_spin_trylock; pv_lock_ops.spin_unlock = xen_spin_unlock; +#endif } #ifdef CONFIG_XEN_DEBUG_FS |