Re: [PATCH net-next] net/smc: add sysctl for smc_limit_hs

[Wen Gu <guwen@linux.alibaba.com>]

On 2024/8/15 21:03, D. Wythe wrote:
> From: "D. Wythe" <alibuda@linux.alibaba.com>
> 
> In commit 48b6190a0042 ("net/smc: Limit SMC visits when handshake workqueue congested"),
> we introduce a mechanism to put constraint on SMC connections visit according to
> the pressure of SMC handshake process.
> 
> At that time, we believed that controlling the feature through netlink was sufficient,
> However, most people have realized now that netlink is not convenient in
> container scenarios, and sysctl is a more suitable approach.
> 
> In addition, it is not reasonable for us to initialize limit_smc_hs in
> smc_pnet_net_init, we made a mistable before. It should be initialized

nit: mistable -> mistake?

> in smc_sysctl_net_init(), just like other systcl.
> 
> Signed-off-by: D. Wythe <alibuda@linux.alibaba.com>
> ---
>   net/smc/smc_pnet.c   |  3 ---
>   net/smc/smc_sysctl.c | 11 +++++++++++
>   2 files changed, 11 insertions(+), 3 deletions(-)
> 
> diff --git a/net/smc/smc_pnet.c b/net/smc/smc_pnet.c
> index 2adb92b..1dd3623 100644
> --- a/net/smc/smc_pnet.c
> +++ b/net/smc/smc_pnet.c
> @@ -887,9 +887,6 @@ int smc_pnet_net_init(struct net *net)
>   
>   	smc_pnet_create_pnetids_list(net);
>   
> -	/* disable handshake limitation by default */
> -	net->smc.limit_smc_hs = 0;
> -
>   	return 0;
>   }
>   
> diff --git a/net/smc/smc_sysctl.c b/net/smc/smc_sysctl.c
> index 13f2bc0..2fab645 100644
> --- a/net/smc/smc_sysctl.c
> +++ b/net/smc/smc_sysctl.c
> @@ -90,6 +90,15 @@
>   		.extra1		= &conns_per_lgr_min,
>   		.extra2		= &conns_per_lgr_max,
>   	},
> +	{
> +		.procname	= "limit_smc_hs",
> +		.data		= &init_net.smc.limit_smc_hs,
> +		.maxlen		= sizeof(int),
> +		.mode		= 0644,
> +		.proc_handler	= proc_dointvec_minmax,
> +		.extra1		= SYSCTL_ZERO,
> +		.extra2		= SYSCTL_ONE,
> +	},
>   };
>   
>   int __net_init smc_sysctl_net_init(struct net *net)
> @@ -121,6 +130,8 @@ int __net_init smc_sysctl_net_init(struct net *net)
>   	WRITE_ONCE(net->smc.sysctl_rmem, net_smc_rmem_init);
>   	net->smc.sysctl_max_links_per_lgr = SMC_LINKS_PER_LGR_MAX_PREFER;
>   	net->smc.sysctl_max_conns_per_lgr = SMC_CONN_PER_LGR_PREFER;
> +	/* disable handshake limitation by default */
> +	net->smc.limit_smc_hs = 0;
>   
>   	return 0;
>