[v3] eal: add notes to SMP memory barrier APIs
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Commit Message
The rte_smp_xx() APIs are deprecated. But it is not mentioned
in the function header.
Added notes in function header for clarification.
Signed-off-by: Ruifeng Wang <ruifeng.wang@arm.com>
---
v3: Added suggested memory ordering semantic for replacement.
Refined deprecation explanation.
v2: Made the notes more specific.
lib/eal/include/generic/rte_atomic.h | 30 ++++++++++++++++++++++++++++
1 file changed, 30 insertions(+)
Comments
03/07/2023 11:56, Ruifeng Wang:
> The rte_smp_xx() APIs are deprecated. But it is not mentioned
> in the function header.
> Added notes in function header for clarification.
>
> Signed-off-by: Ruifeng Wang <ruifeng.wang@arm.com>
> ---
> v3: Added suggested memory ordering semantic for replacement.
> Refined deprecation explanation.
> v2: Made the notes more specific.
>
> lib/eal/include/generic/rte_atomic.h | 30 ++++++++++++++++++++++++++++
> 1 file changed, 30 insertions(+)
>
> diff --git a/lib/eal/include/generic/rte_atomic.h b/lib/eal/include/generic/rte_atomic.h
> index 58df843c54..aef44e2455 100644
> --- a/lib/eal/include/generic/rte_atomic.h
> +++ b/lib/eal/include/generic/rte_atomic.h
> @@ -55,6 +55,14 @@ static inline void rte_rmb(void);
> * Guarantees that the LOAD and STORE operations that precede the
> * rte_smp_mb() call are globally visible across the lcores
> * before the LOAD and STORE operations that follows it.
> + *
> + * @note
> + * This function is deprecated.
> + * It provides similar synchronization primitive as atomic fence,
> + * but has different syntax and memory ordering semantic. Hence
> + * deprecated for the simplicity of memory ordering semantics in use.
> + *
> + * rte_atomic_thread_fence(__ATOMIC_ACQ_REL) should be used instead.
> */
> static inline void rte_smp_mb(void);
>
> @@ -64,6 +72,17 @@ static inline void rte_smp_mb(void);
> * Guarantees that the STORE operations that precede the
> * rte_smp_wmb() call are globally visible across the lcores
> * before the STORE operations that follows it.
> + *
> + * @note
> + * This function is deprecated.
> + * It provides similar synchronization primitive as atomic fence,
> + * but has different syntax and memory ordering semantic. Hence
> + * deprecated for the simplicity of memory ordering semantics in use.
> + *
> + * rte_atomic_thread_fence(__ATOMIC_RELEASE) should be used instead.
> + * The fence also guarantees LOAD operations that precede the call
> + * are globally visible across the lcores before the STORE operations
> + * that follows it.
> */
> static inline void rte_smp_wmb(void);
>
> @@ -73,6 +92,17 @@ static inline void rte_smp_wmb(void);
> * Guarantees that the LOAD operations that precede the
> * rte_smp_rmb() call are globally visible across the lcores
> * before the LOAD operations that follows it.
> + *
> + * @note
> + * This function is deprecated.
> + * It provides similar synchronization primitive as atomic fence,
> + * but has different syntax and memory ordering semantic. Hence
> + * deprecated for the simplicity of memory ordering semantics in use.
> + *
> + * rte_atomic_thread_fence(__ATOMIC_ACQUIRE) should be used instead.
> + * The fence also guarantees LOAD operations that precede the call
> + * are globally visible across the lcores before the STORE operations
> + * that follows it.
> */
> static inline void rte_smp_rmb(void);
> ///@}
There was no more comment.
Applied, thanks.
@@ -55,6 +55,14 @@ static inline void rte_rmb(void);
* Guarantees that the LOAD and STORE operations that precede the
* rte_smp_mb() call are globally visible across the lcores
* before the LOAD and STORE operations that follows it.
+ *
+ * @note
+ * This function is deprecated.
+ * It provides similar synchronization primitive as atomic fence,
+ * but has different syntax and memory ordering semantic. Hence
+ * deprecated for the simplicity of memory ordering semantics in use.
+ *
+ * rte_atomic_thread_fence(__ATOMIC_ACQ_REL) should be used instead.
*/
static inline void rte_smp_mb(void);
@@ -64,6 +72,17 @@ static inline void rte_smp_mb(void);
* Guarantees that the STORE operations that precede the
* rte_smp_wmb() call are globally visible across the lcores
* before the STORE operations that follows it.
+ *
+ * @note
+ * This function is deprecated.
+ * It provides similar synchronization primitive as atomic fence,
+ * but has different syntax and memory ordering semantic. Hence
+ * deprecated for the simplicity of memory ordering semantics in use.
+ *
+ * rte_atomic_thread_fence(__ATOMIC_RELEASE) should be used instead.
+ * The fence also guarantees LOAD operations that precede the call
+ * are globally visible across the lcores before the STORE operations
+ * that follows it.
*/
static inline void rte_smp_wmb(void);
@@ -73,6 +92,17 @@ static inline void rte_smp_wmb(void);
* Guarantees that the LOAD operations that precede the
* rte_smp_rmb() call are globally visible across the lcores
* before the LOAD operations that follows it.
+ *
+ * @note
+ * This function is deprecated.
+ * It provides similar synchronization primitive as atomic fence,
+ * but has different syntax and memory ordering semantic. Hence
+ * deprecated for the simplicity of memory ordering semantics in use.
+ *
+ * rte_atomic_thread_fence(__ATOMIC_ACQUIRE) should be used instead.
+ * The fence also guarantees LOAD operations that precede the call
+ * are globally visible across the lcores before the STORE operations
+ * that follows it.
*/
static inline void rte_smp_rmb(void);
///@}