[v4,5/6] mempool: avoid floating point expression in static assertion
Checks
Commit Message
Clang does not handle casts in static_assert() expressions.
It doesn't like use of floating point to calculate threshold.
Use a different expression with same effect.
Modify comment in mlx5 so that developers don't go searching
for old value.
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
drivers/net/mlx5/mlx5_rxq.c | 2 +-
lib/mempool/rte_mempool.c | 7 ++++---
2 files changed, 5 insertions(+), 4 deletions(-)
Comments
> From: Stephen Hemminger [mailto:stephen@networkplumber.org]
> Sent: Wednesday, 17 January 2024 19.20
>
> Clang does not handle casts in static_assert() expressions.
> It doesn't like use of floating point to calculate threshold.
> Use a different expression with same effect.
>
> Modify comment in mlx5 so that developers don't go searching
> for old value.
>
> Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Acked-by: Morten Brørup <mb@smartsharesystems.com>
> Clang does not handle casts in static_assert() expressions.
> It doesn't like use of floating point to calculate threshold.
> Use a different expression with same effect.
>
> Modify comment in mlx5 so that developers don't go searching
> for old value.
>
> Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
> ---
> drivers/net/mlx5/mlx5_rxq.c | 2 +-
> lib/mempool/rte_mempool.c | 7 ++++---
> 2 files changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/net/mlx5/mlx5_rxq.c b/drivers/net/mlx5/mlx5_rxq.c
> index 1bb036afebb3..7d972b6d927c 100644
> --- a/drivers/net/mlx5/mlx5_rxq.c
> +++ b/drivers/net/mlx5/mlx5_rxq.c
> @@ -1444,7 +1444,7 @@ mlx5_mprq_alloc_mp(struct rte_eth_dev *dev)
> /*
> * rte_mempool_create_empty() has sanity check to refuse large cache
> * size compared to the number of elements.
> - * CACHE_FLUSHTHRESH_MULTIPLIER is defined in a C file, so using a
> + * CALC_CACHE_FLUSHTHRESH() is defined in a C file, so using a
> * constant number 2 instead.
> */
> obj_num = RTE_MAX(obj_num, MLX5_MPRQ_MP_CACHE_SZ * 2);
> diff --git a/lib/mempool/rte_mempool.c b/lib/mempool/rte_mempool.c
> index b7a19bea7185..12390a2c8155 100644
> --- a/lib/mempool/rte_mempool.c
> +++ b/lib/mempool/rte_mempool.c
> @@ -50,9 +50,10 @@ static void
> mempool_event_callback_invoke(enum rte_mempool_event event,
> struct rte_mempool *mp);
>
> -#define CACHE_FLUSHTHRESH_MULTIPLIER 1.5
> -#define CALC_CACHE_FLUSHTHRESH(c) \
> - ((typeof(c))((c) * CACHE_FLUSHTHRESH_MULTIPLIER))
> +/* Note: avoid using floating point since that compiler
> + * may not think that is constant.
> + */
> +#define CALC_CACHE_FLUSHTHRESH(c) (((c) * 3) / 2)
>
> #if defined(RTE_ARCH_X86)
> /*
Acked-by: Konstantin Ananyev <konstantin.ananyev@huawei.com>
> --
> 2.43.0
On 1/17/24 21:32, Morten Brørup wrote:
>> From: Stephen Hemminger [mailto:stephen@networkplumber.org]
>> Sent: Wednesday, 17 January 2024 19.20
>>
>> Clang does not handle casts in static_assert() expressions.
>> It doesn't like use of floating point to calculate threshold.
>> Use a different expression with same effect.
>>
>> Modify comment in mlx5 so that developers don't go searching
>> for old value.
>>
>> Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
>
> Acked-by: Morten Brørup <mb@smartsharesystems.com>
>
Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
@@ -1444,7 +1444,7 @@ mlx5_mprq_alloc_mp(struct rte_eth_dev *dev)
/*
* rte_mempool_create_empty() has sanity check to refuse large cache
* size compared to the number of elements.
- * CACHE_FLUSHTHRESH_MULTIPLIER is defined in a C file, so using a
+ * CALC_CACHE_FLUSHTHRESH() is defined in a C file, so using a
* constant number 2 instead.
*/
obj_num = RTE_MAX(obj_num, MLX5_MPRQ_MP_CACHE_SZ * 2);
@@ -50,9 +50,10 @@ static void
mempool_event_callback_invoke(enum rte_mempool_event event,
struct rte_mempool *mp);
-#define CACHE_FLUSHTHRESH_MULTIPLIER 1.5
-#define CALC_CACHE_FLUSHTHRESH(c) \
- ((typeof(c))((c) * CACHE_FLUSHTHRESH_MULTIPLIER))
+/* Note: avoid using floating point since that compiler
+ * may not think that is constant.
+ */
+#define CALC_CACHE_FLUSHTHRESH(c) (((c) * 3) / 2)
#if defined(RTE_ARCH_X86)
/*