Hi Linus,
Please pull a single patch for alpha, one that enables
ARCH_USE_CMPXCHG_LOCKREF and offers around an 8% performance
improvement on a little benchmark that you wrote.
Thanks,
Matt
The following changes since commit 64291f7db5bd8150a74ad2036f1037e6a0428df2:
Linux 4.2 (2015-08-30 11:34:09 -0700)
are available in the git repository at:
git://git.kernel.org/pub/scm/linux/kernel/git/mattst88/alpha.git for-linus
for you to fetch changes up to 8f8dcb3f7fe4febbfa96e64d4ad47de958c5cc34:
alpha: select CONFIG_ARCH_USE_CMPXCHG_LOCKREF. (2015-08-30 18:01:16 -0700)
----------------------------------------------------------------
Matt Turner (1):
alpha: select CONFIG_ARCH_USE_CMPXCHG_LOCKREF.
arch/alpha/Kconfig | 1 +
arch/alpha/include/asm/spinlock.h | 5 +++++
2 files changed, 6 insertions(+)
diff --git a/arch/alpha/Kconfig b/arch/alpha/Kconfig
index bf9e9d3..f515a4d 100644
--- a/arch/alpha/Kconfig
+++ b/arch/alpha/Kconfig
@@ -3,6 +3,7 @@ config ALPHA
default y
select ARCH_MIGHT_HAVE_PC_PARPORT
select ARCH_MIGHT_HAVE_PC_SERIO
+ select ARCH_USE_CMPXCHG_LOCKREF
select HAVE_AOUT
select HAVE_IDE
select HAVE_OPROFILE
diff --git a/arch/alpha/include/asm/spinlock.h b/arch/alpha/include/asm/spinlock.h
index 37b570d..fed9c6f 100644
--- a/arch/alpha/include/asm/spinlock.h
+++ b/arch/alpha/include/asm/spinlock.h
@@ -16,6 +16,11 @@
#define arch_spin_unlock_wait(x) \
do { cpu_relax(); } while ((x)->lock)
+static inline int arch_spin_value_unlocked(arch_spinlock_t lock)
+{
+ return lock.lock == 0;
+}
+
static inline void arch_spin_unlock(arch_spinlock_t * lock)
{
mb();
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