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From: Dariusz Sosnowski <dsosnowski@nvidia.com>
To: Rongwei Liu <rongweil@nvidia.com>
Cc: <dev@dpdk.org>, <matan@nvidia.com>, <viacheslavo@nvidia.com>,
	<orika@nvidia.com>, <suanmingm@nvidia.com>, <thomas@monjalon.net>,
	Bing Zhao <bingz@nvidia.com>
Subject: Re: [PATCH v1] net/mlx5: remove counter alignment
Date: Tue, 28 Oct 2025 11:14:27 +0100	[thread overview]
Message-ID: <20251028101427.7swzqvc5o3ofzdxg@ds-vm-debian.local> (raw)
In-Reply-To: <20251028092611.1755141-1-rongweil@nvidia.com>

Hi,

On Tue, Oct 28, 2025 at 11:26:11AM +0200, Rongwei Liu wrote:
> The memory footprint was increased due to the alignment.

s/alignment/overalignment/

For clarity that the relevant fields were overaligned.

> 
> Signed-off-by: Rongwei Liu <rongweil@nvidia.com>
> ---

Since this is a bug fix, please add Fixes tag for the following commit:

	820ca7361bb7 ("net/mlx5: fix flow aging race condition")

Cc-ing to stable mailing list won't be needed,
because the offending patch is only in 25.11-rc1

>  drivers/net/mlx5/mlx5_hws_cnt.h | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/mlx5/mlx5_hws_cnt.h b/drivers/net/mlx5/mlx5_hws_cnt.h
> index f5b7e8f643..d19a7bf37e 100644
> --- a/drivers/net/mlx5/mlx5_hws_cnt.h
> +++ b/drivers/net/mlx5/mlx5_hws_cnt.h
> @@ -43,7 +43,7 @@ struct mlx5_hws_cnt_dcs_mng {
>  };
>  
>  union mlx5_hws_cnt_state {
> -	alignas(RTE_CACHE_LINE_SIZE) RTE_ATOMIC(uint32_t)data;
> +	RTE_ATOMIC(uint32_t)data;

Please add a space between `RTE_ATOMIC(uint32_t)` and `data`.

>  	struct {
>  		uint32_t in_used:1;
>  		/* Indicator whether this counter in used or in pool. */
> @@ -64,7 +64,7 @@ struct mlx5_hws_cnt {
>  	struct flow_counter_stats reset;
>  	union mlx5_hws_cnt_state cnt_state;
>  	/* This struct is only meaningful when user own this counter. */
> -	alignas(RTE_CACHE_LINE_SIZE) RTE_ATOMIC(uint32_t)query_gen_when_free;
> +	RTE_ATOMIC(uint32_t)query_gen_when_free;

Same as above.

>  	/*
>  	 * When PMD own this counter (user put back counter to PMD
>  	 * counter pool, i.e), this field recorded value of counter
> -- 
> 2.27.0
> 

Best regards,
Dariusz Sosnowski

      reply	other threads:[~2025-10-28 10:15 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-10-28  9:26 Rongwei Liu
2025-10-28 10:14 ` Dariusz Sosnowski [this message]

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