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Commit 485832a5 authored by Andi Kleen's avatar Andi Kleen Committed by Linus Torvalds
Browse files

[PATCH] x86_64: Use int operations in spinlocks to support more than 128 CPUs spinning. 



Pointed out by Eric Dumazet

Signed-off-by: default avatarAndi Kleen <ak@suse.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 8315eca2

include/asm-x86_64/spinlock.h

+6 −6
Original line number Original line Diff line number Diff line
@@ -18,22 +18,22 @@ 
 */

 */





#define __raw_spin_is_locked(x) \

#define __raw_spin_is_locked(x) \

		(*(volatile signed char *)(&(x)->slock) <= 0)

		(*(volatile signed int *)(&(x)->slock) <= 0)





#define __raw_spin_lock_string \

#define __raw_spin_lock_string \

	"\n1:\t" \

	"\n1:\t" \

	"lock ; decb %0\n\t" \

	"lock ; decl %0\n\t" \

	"js 2f\n" \

	"js 2f\n" \

	LOCK_SECTION_START("") \

	LOCK_SECTION_START("") \

	"2:\t" \

	"2:\t" \

	"rep;nop\n\t" \

	"rep;nop\n\t" \

	"cmpb $0,%0\n\t" \

	"cmpl $0,%0\n\t" \

	"jle 2b\n\t" \

	"jle 2b\n\t" \

	"jmp 1b\n" \

	"jmp 1b\n" \

	LOCK_SECTION_END

	LOCK_SECTION_END





#define __raw_spin_unlock_string \

#define __raw_spin_unlock_string \

	"movb $1,%0" \

	"movl $1,%0" \

		:"=m" (lock->slock) : : "memory"

		:"=m" (lock->slock) : : "memory"





static inline void __raw_spin_lock(raw_spinlock_t *lock)

static inline void __raw_spin_lock(raw_spinlock_t *lock)
@@ -47,10 +47,10 @@ static inline void __raw_spin_lock(raw_spinlock_t *lock) 




static inline int __raw_spin_trylock(raw_spinlock_t *lock)

static inline int __raw_spin_trylock(raw_spinlock_t *lock)

{

{

	char oldval;

	int oldval;





	__asm__ __volatile__(

	__asm__ __volatile__(

		"xchgb %b0,%1"

		"xchgl %0,%1"

		:"=q" (oldval), "=m" (lock->slock)

		:"=q" (oldval), "=m" (lock->slock)

		:"0" (0) : "memory");

		:"0" (0) : "memory");