diff mbox series

[v5,5/6] mempool: avoid floating point expression in static assertion

Message ID 20240118165315.63959-6-stephen@networkplumber.org (mailing list archive)
State Accepted, archived
Delegated to: David Marchand
Headers
Series use static_assert for build error reports |

Checks

Context Check Description
ci/checkpatch success coding style OK

Commit Message

Stephen Hemminger Jan. 18, 2024, 4:51 p.m. UTC 
  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: Konstantin Ananyev <konstantin.ananyev@huawei.com>
Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
---
 drivers/net/mlx5/mlx5_rxq.c | 2 +-
 lib/mempool/rte_mempool.c   | 7 ++++---
 2 files changed, 5 insertions(+), 4 deletions(-)

Comments

Morten Brørup Jan. 18, 2024, 6:46 p.m. UTC | #1 
> From: Stephen Hemminger [mailto:stephen@networkplumber.org]
> Sent: Thursday, 18 January 2024 17.51
> 
> 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: Konstantin Ananyev <konstantin.ananyev@huawei.com>
> Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
> ---

Reviewed-by: Morten Brørup <mb@smartsharesystems.com>
Slava Ovsiienko Jan. 19, 2024, 10:07 a.m. UTC | #2 
> -----Original Message-----
> From: Stephen Hemminger <stephen@networkplumber.org>
> Sent: Thursday, January 18, 2024 6:51 PM
> To: dev@dpdk.org
> Cc: Stephen Hemminger <stephen@networkplumber.org>; Konstantin Ananyev
> <konstantin.ananyev@huawei.com>; Andrew Rybchenko
> <andrew.rybchenko@oktetlabs.ru>; Dariusz Sosnowski
> <dsosnowski@nvidia.com>; Slava Ovsiienko <viacheslavo@nvidia.com>; Ori
> Kam <orika@nvidia.com>; Suanming Mou <suanmingm@nvidia.com>; Matan
> Azrad <matan@nvidia.com>; Morten Brørup <mb@smartsharesystems.com>
> Subject: [PATCH v5 5/6] mempool: avoid floating point expression in static
> assertion
> 
> 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: Konstantin Ananyev <konstantin.ananyev@huawei.com>
> Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
Acked-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>
diff mbox series

Patch

diff --git a/drivers/net/mlx5/mlx5_rxq.c b/drivers/net/mlx5/mlx5_rxq.c
index 1bb036afebb3..ca2eeedc9de3 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)
 /*