[dpdk-dev] [PATCH v8 01/15] eal: introduce atomic exchange operation
Stephen Hemminger
stephen at networkplumber.org
Fri Jan 26 03:01:37 CET 2018
To handle atomic update of link status (64 bit), every driver
was doing its own version using cmpset.
Atomic exchange is a useful primitive in its own right;
therefore make it a EAL routine.
Signed-off-by: Stephen Hemminger <stephen at networkplumber.org>
---
.../common/include/arch/ppc_64/rte_atomic.h | 21 +++++-
.../common/include/arch/x86/rte_atomic.h | 24 +++++++
.../common/include/arch/x86/rte_atomic_32.h | 12 ++++
.../common/include/arch/x86/rte_atomic_64.h | 12 ++++
lib/librte_eal/common/include/generic/rte_atomic.h | 78 ++++++++++++++++++++++
5 files changed, 146 insertions(+), 1 deletion(-)
diff --git a/lib/librte_eal/common/include/arch/ppc_64/rte_atomic.h b/lib/librte_eal/common/include/arch/ppc_64/rte_atomic.h
index 150810cdb365..11fa1117a255 100644
--- a/lib/librte_eal/common/include/arch/ppc_64/rte_atomic.h
+++ b/lib/librte_eal/common/include/arch/ppc_64/rte_atomic.h
@@ -132,6 +132,12 @@ static inline int rte_atomic16_dec_and_test(rte_atomic16_t *v)
return __atomic_sub_fetch(&v->cnt, 1, __ATOMIC_ACQUIRE) == 0;
}
+static inline uint16_t
+rte_atomic16_exchange(volatile uint16_t *dst, uint16_t val)
+{
+ return __atomic_exchange_2(dst, val, __ATOMIC_SEQ_CST);
+}
+
/*------------------------- 32 bit atomic operations -------------------------*/
static inline int
@@ -233,6 +239,13 @@ static inline int rte_atomic32_dec_and_test(rte_atomic32_t *v)
return ret == 0;
}
+
+static inline uint32_t
+rte_atomic32_exchange(volatile uint32_t *dst, uint32_t val)
+{
+ return __atomic_exchange_4(dst, val, __ATOMIC_SEQ_CST);
+}
+
/*------------------------- 64 bit atomic operations -------------------------*/
static inline int
@@ -427,7 +440,6 @@ static inline int rte_atomic64_test_and_set(rte_atomic64_t *v)
{
return rte_atomic64_cmpset((volatile uint64_t *)&v->cnt, 0, 1);
}
-
/**
* Atomically set a 64-bit counter to 0.
*
@@ -438,6 +450,13 @@ static inline void rte_atomic64_clear(rte_atomic64_t *v)
{
v->cnt = 0;
}
+
+static inline uint64_t
+rte_atomic64_exchange(volatile uint64_t *dst, uint64_t val)
+{
+ return __atomic_exchange_4(dst, val, __ATOMIC_SEQ_CST);
+}
+
#endif
#ifdef __cplusplus
diff --git a/lib/librte_eal/common/include/arch/x86/rte_atomic.h b/lib/librte_eal/common/include/arch/x86/rte_atomic.h
index 36cfabc38f09..55bfc3903cdc 100644
--- a/lib/librte_eal/common/include/arch/x86/rte_atomic.h
+++ b/lib/librte_eal/common/include/arch/x86/rte_atomic.h
@@ -60,6 +60,18 @@ rte_atomic16_cmpset(volatile uint16_t *dst, uint16_t exp, uint16_t src)
return res;
}
+static inline uint16_t
+rte_atomic16_exchange(volatile uint16_t *dst, uint16_t val)
+{
+ asm volatile(
+ MPLOCKED
+ "xchgw %0, %1;"
+ : "=r" (val), "=m" (*dst)
+ : "0" (val), "m" (*dst)
+ : "memory"); /* no-clobber list */
+ return val;
+}
+
static inline int rte_atomic16_test_and_set(rte_atomic16_t *v)
{
return rte_atomic16_cmpset((volatile uint16_t *)&v->cnt, 0, 1);
@@ -134,6 +146,18 @@ rte_atomic32_cmpset(volatile uint32_t *dst, uint32_t exp, uint32_t src)
return res;
}
+static inline uint32_t
+rte_atomic32_exchange(volatile uint32_t *dst, uint32_t val)
+{
+ asm volatile(
+ MPLOCKED
+ "xchgl %0, %1;"
+ : "=r" (val), "=m" (*dst)
+ : "0" (val), "m" (*dst)
+ : "memory"); /* no-clobber list */
+ return val;
+}
+
static inline int rte_atomic32_test_and_set(rte_atomic32_t *v)
{
return rte_atomic32_cmpset((volatile uint32_t *)&v->cnt, 0, 1);
diff --git a/lib/librte_eal/common/include/arch/x86/rte_atomic_32.h b/lib/librte_eal/common/include/arch/x86/rte_atomic_32.h
index fb3abf187998..8d711b6f685d 100644
--- a/lib/librte_eal/common/include/arch/x86/rte_atomic_32.h
+++ b/lib/librte_eal/common/include/arch/x86/rte_atomic_32.h
@@ -98,6 +98,18 @@ rte_atomic64_cmpset(volatile uint64_t *dst, uint64_t exp, uint64_t src)
return res;
}
+static inline uint64_t
+rte_atomic64_exchange(volatile uint64_t *dest, uint64_t val)
+{
+ uint64_t old;
+
+ do {
+ old = *dest;
+ } while (rte_atomic64_cmpset(dest, old, val));
+
+ return old;
+}
+
static inline void
rte_atomic64_init(rte_atomic64_t *v)
{
diff --git a/lib/librte_eal/common/include/arch/x86/rte_atomic_64.h b/lib/librte_eal/common/include/arch/x86/rte_atomic_64.h
index 1a53a766bd72..fd2ec9c53796 100644
--- a/lib/librte_eal/common/include/arch/x86/rte_atomic_64.h
+++ b/lib/librte_eal/common/include/arch/x86/rte_atomic_64.h
@@ -71,6 +71,18 @@ rte_atomic64_cmpset(volatile uint64_t *dst, uint64_t exp, uint64_t src)
return res;
}
+static inline uint64_t
+rte_atomic64_exchange(volatile uint64_t *dst, uint64_t val)
+{
+ asm volatile(
+ MPLOCKED
+ "xchgq %0, %1;"
+ : "=r" (val), "=m" (*dst)
+ : "0" (val), "m" (*dst)
+ : "memory"); /* no-clobber list */
+ return val;
+}
+
static inline void
rte_atomic64_init(rte_atomic64_t *v)
{
diff --git a/lib/librte_eal/common/include/generic/rte_atomic.h b/lib/librte_eal/common/include/generic/rte_atomic.h
index 3ba7245a3e17..bf12162d02f4 100644
--- a/lib/librte_eal/common/include/generic/rte_atomic.h
+++ b/lib/librte_eal/common/include/generic/rte_atomic.h
@@ -139,6 +139,32 @@ rte_atomic16_cmpset(volatile uint16_t *dst, uint16_t exp, uint16_t src)
}
#endif
+/**
+ * Atomic exchange.
+ *
+ * (atomic) equivalent to:
+ * ret = *dst
+ * *dst = val;
+ * return ret;
+ *
+ * @param dst
+ * The destination location into which the value will be written.
+ * @param val
+ * The new value.
+ * @return
+ * The original value at that location
+ */
+static inline uint16_t
+rte_atomic16_exchange(volatile uint16_t *dst, uint16_t val);
+
+#ifdef RTE_FORCE_INTRINSICS
+static inline uint16_t
+rte_atomic16_exchange(volatile uint16_t *dst, uint16_t val)
+{
+ return __atomic_exchange_2(dst, val, __ATOMIC_SEQ_CST);
+}
+#endif
+
/**
* The atomic counter structure.
*/
@@ -392,6 +418,32 @@ rte_atomic32_cmpset(volatile uint32_t *dst, uint32_t exp, uint32_t src)
}
#endif
+/**
+ * Atomic exchange.
+ *
+ * (atomic) equivalent to:
+ * ret = *dst
+ * *dst = val;
+ * return ret;
+ *
+ * @param dst
+ * The destination location into which the value will be written.
+ * @param val
+ * The new value.
+ * @return
+ * The original value at that location
+ */
+static inline uint32_t
+rte_atomic32_exchange(volatile uint32_t *dst, uint32_t val);
+
+#ifdef RTE_FORCE_INTRINSICS
+static inline uint32_t
+rte_atomic32_exchange(volatile uint32_t *dst, uint32_t val)
+{
+ return __atomic_exchange_4(dst, val, __ATOMIC_SEQ_CST);
+}
+#endif
+
/**
* The atomic counter structure.
*/
@@ -644,6 +696,32 @@ rte_atomic64_cmpset(volatile uint64_t *dst, uint64_t exp, uint64_t src)
}
#endif
+/**
+ * Atomic exchange.
+ *
+ * (atomic) equivalent to:
+ * ret = *dst
+ * *dst = val;
+ * return ret;
+ *
+ * @param dst
+ * The destination location into which the value will be written.
+ * @param val
+ * The new value.
+ * @return
+ * The original value at that location
+ */
+static inline uint64_t
+rte_atomic64_exchange(volatile uint64_t *dst, uint64_t val);
+
+#ifdef RTE_FORCE_INTRINSICS
+static inline uint64_t
+rte_atomic64_exchange(volatile uint64_t *dst, uint64_t val)
+{
+ return __atomic_exchange_8(dst, val, __ATOMIC_SEQ_CST);
+}
+#endif
+
/**
* The atomic counter structure.
*/
--
2.15.1
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