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Commit bf67fd31 authored by Will Deacon's avatar Will Deacon Committed by Russell King
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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: default avatarWill Deacon <will.deacon@arm.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent e38361d0

arch/arm/include/asm/mcs_spinlock.h

0 → 100644
+23 −0
Original line number Diff line number Diff line 
#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 */