From efc1d23b3d9af8cbff9f26677d67fb9c1b9cb792 Mon Sep 17 00:00:00 2001
From: Heiko Carstens <heiko.carstens@de.ibm.com>
Date: Thu, 5 Sep 2013 13:26:17 +0200
Subject: [PATCH] s390: enable ARCH_USE_CMPXCHG_LOCKREF
Enable ARCH_USE_CMPXCHG_LOCKREF since it shows performance improvements
with Linus' simple stat() test case of up to 50% on a 30 cpu system.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
---
arch/s390/Kconfig | 1 +
arch/s390/include/asm/spinlock.h | 5 +++++
2 files changed, 6 insertions(+)
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index d3fa84070b828..7143793859fad 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -93,6 +93,7 @@ config S390
select ARCH_INLINE_WRITE_UNLOCK_IRQ
select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE
select ARCH_SAVE_PAGE_KEYS if HIBERNATION
+ select ARCH_USE_CMPXCHG_LOCKREF
select ARCH_WANT_IPC_PARSE_VERSION
select BUILDTIME_EXTABLE_SORT
select CLONE_BACKWARDS2
diff --git a/arch/s390/include/asm/spinlock.h b/arch/s390/include/asm/spinlock.h
index 701fe8c59e1f0..83e5d216105e8 100644
--- a/arch/s390/include/asm/spinlock.h
+++ b/arch/s390/include/asm/spinlock.h
@@ -44,6 +44,11 @@ extern void arch_spin_lock_wait_flags(arch_spinlock_t *, unsigned long flags);
extern int arch_spin_trylock_retry(arch_spinlock_t *);
extern void arch_spin_relax(arch_spinlock_t *lock);
+static inline int arch_spin_value_unlocked(arch_spinlock_t lock)
+{
+ return lock.owner_cpu == 0;
+}
+
static inline void arch_spin_lock(arch_spinlock_t *lp)
{
int old;
--
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