On Thu, Aug 30, 2018 at 04:29:20PM +0200, Peter Zijlstra wrote:
> Also, once it all works, they should look at switching to _relaxed
> atomics for LL/SC.
A little something like so.. should save a few smp_mb().
---
diff --git a/arch/arc/include/asm/atomic.h b/arch/arc/include/asm/atomic.h
index 4e0072730241..714b54c308b0 100644
--- a/arch/arc/include/asm/atomic.h
+++ b/arch/arc/include/asm/atomic.h
@@ -44,7 +44,7 @@ static inline void atomic_##op(int i, atomic_t *v)
\
} \
#define ATOMIC_OP_RETURN(op, c_op, asm_op) \
-static inline int atomic_##op##_return(int i, atomic_t *v) \
+static inline int atomic_##op##_return_relaxed(int i, atomic_t *v) \
{ \
unsigned int val; \
\
@@ -69,8 +69,11 @@ static inline int atomic_##op##_return(int i, atomic_t *v)
\
return val; \
}
+#define atomic_add_return_relaxed atomic_add_return_relaxed
+#define atomic_sub_return_relaxed atomic_sub_return_relaxed
+
#define ATOMIC_FETCH_OP(op, c_op, asm_op) \
-static inline int atomic_fetch_##op(int i, atomic_t *v)
\
+static inline int atomic_fetch_##op##_relaxed(int i, atomic_t *v) \
{ \
unsigned int val, orig; \
\
@@ -96,6 +99,14 @@ static inline int atomic_fetch_##op(int i, atomic_t *v)
\
return orig; \
}
+#define atomic_fetch_add_relaxed atomic_fetch_add_relaxed
+#define atomic_fetch_sub_relaxed atomic_fetch_sub_relaxed
+
+#define atomic_fetch_and_relaxed atomic_fetch_and_relaxed
+#define atomic_fetch_andnot_relaxed atomic_fetch_andnot_relaxed
+#define atomic_fetch_or_relaxed atomic_fetch_or_relaxed
+#define atomic_fetch_xor_relaxed atomic_fetch_xor_relaxed
+
#else /* !CONFIG_ARC_HAS_LLSC */
#ifndef CONFIG_SMP
@@ -379,7 +390,7 @@ static inline void atomic64_##op(long long a, atomic64_t
*v) \
} \
#define ATOMIC64_OP_RETURN(op, op1, op2) \
-static inline long long atomic64_##op##_return(long long a, atomic64_t *v)
\
+static inline long long atomic64_##op##_return_relaxed(long long a, atomic64_t
*v) \
{ \
unsigned long long val; \
\
@@ -401,8 +412,11 @@ static inline long long atomic64_##op##_return(long long
a, atomic64_t *v) \
return val; \
}
+#define atomic64_add_return_relaxed atomic64_add_return_relaxed
+#define atomic64_sub_return_relaxed atomic64_sub_return_relaxed
+
#define ATOMIC64_FETCH_OP(op, op1, op2)
\
-static inline long long atomic64_fetch_##op(long long a, atomic64_t *v)
\
+static inline long long atomic64_fetch_##op##_relaxed(long long a, atomic64_t
*v) \
{ \
unsigned long long val, orig; \
\
@@ -424,6 +438,14 @@ static inline long long atomic64_fetch_##op(long long a,
atomic64_t *v) \
return orig; \
}
+#define atomic64_fetch_add_relaxed atomic64_fetch_add_relaxed
+#define atomic64_fetch_sub_relaxed atomic64_fetch_sub_relaxed
+
+#define atomic64_fetch_and_relaxed atomic64_fetch_and_relaxed
+#define atomic64_fetch_andnot_relaxed atomic64_fetch_andnot_relaxed
+#define atomic64_fetch_or_relaxed atomic64_fetch_or_relaxed
+#define atomic64_fetch_xor_relaxed atomic64_fetch_xor_relaxed
+
#define ATOMIC64_OPS(op, op1, op2) \
ATOMIC64_OP(op, op1, op2) \
ATOMIC64_OP_RETURN(op, op1, op2) \
@@ -434,6 +456,12 @@ static inline long long atomic64_fetch_##op(long long a,
atomic64_t *v) \
ATOMIC64_OPS(add, add.f, adc)
ATOMIC64_OPS(sub, sub.f, sbc)
+
+#undef ATOMIC64_OPS
+#define ATOMIC64_OPS(op, op1, op2) \
+ ATOMIC64_OP(op, op1, op2) \
+ ATOMIC64_FETCH_OP(op, op1, op2)
+
ATOMIC64_OPS(and, and, and)
ATOMIC64_OPS(andnot, bic, bic)
ATOMIC64_OPS(or, or, or)
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