linux/arch/arm/include/asm/mcs_spinlock.h
Will Deacon bf67fd3142 ARM: 8098/1: mcs lock: implement wfe-based polling for MCS locking
This patch introduces a wfe-based polling loop for spinning on contended
MCS locks and waking up corresponding waiters when the lock is released.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-07-18 12:29:35 +01:00

24 lines
531 B
C

#ifndef __ASM_MCS_LOCK_H
#define __ASM_MCS_LOCK_H
#ifdef CONFIG_SMP
#include <asm/spinlock.h>
/* MCS spin-locking. */
#define arch_mcs_spin_lock_contended(lock) \
do { \
/* Ensure prior stores are observed before we enter wfe. */ \
smp_mb(); \
while (!(smp_load_acquire(lock))) \
wfe(); \
} while (0) \
#define arch_mcs_spin_unlock_contended(lock) \
do { \
smp_store_release(lock, 1); \
dsb_sev(); \
} while (0)
#endif /* CONFIG_SMP */
#endif /* __ASM_MCS_LOCK_H */