From: Alexander Sverdlin <alexander.sverdlin@xxxxxxxxx>
On Octeon mmiowb() is SYNCW, which is already contained in
smp_store_release(). Removing superfluous barrier brings around 10%
performance on uncontended tight spinlock loops.
Signed-off-by: Alexander Sverdlin <alexander.sverdlin@xxxxxxxxx>
---
arch/mips/include/asm/spinlock.h | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/mips/include/asm/spinlock.h b/arch/mips/include/asm/spinlock.h
index 0a707f3..fbe97b4 100644
--- a/arch/mips/include/asm/spinlock.h
+++ b/arch/mips/include/asm/spinlock.h
@@ -21,8 +21,10 @@
*/
static inline void queued_spin_unlock(struct qspinlock *lock)
{
+#ifndef CONFIG_CPU_CAVIUM_OCTEON
/* This could be optimised with ARCH_HAS_MMIOWB */
mmiowb();
+#endif
smp_store_release(&lock->locked, 0);
#ifdef CONFIG_CPU_CAVIUM_OCTEON
nudge_writes();
--
2.10.2
