Re: [PATCH net-next 2/2] net/smc: add sysctl for max conns per lgr for SMC-R v2.1

[Dust Li <dust.li@linux.alibaba.com>]

On Wed, Nov 22, 2023 at 09:52:58PM +0800, Guangguan Wang wrote:
>Add a new sysctl: net.smc.smcr_max_conns_per_lgr, which is
>used to control the preferred max connections per lgr for
>SMC-R v2.1. The default value of this sysctl is 255, and
>the acceptable value ranges from 16 to 255.
>
>Signed-off-by: Guangguan Wang <guangguan.wang@linux.alibaba.com>

Reviewed-by: Dust Li <dust.li@linux.alibaba.com>

>---
> Documentation/networking/smc-sysctl.rst |  6 ++++++
> include/net/netns/smc.h                 |  1 +
> net/smc/smc_clc.c                       |  5 +++--
> net/smc/smc_sysctl.c                    | 12 ++++++++++++
> net/smc/smc_sysctl.h                    |  1 +
> 5 files changed, 23 insertions(+), 2 deletions(-)
>
>diff --git a/Documentation/networking/smc-sysctl.rst b/Documentation/networking/smc-sysctl.rst
>index c6ef86ef4c4f..a874d007f2db 100644
>--- a/Documentation/networking/smc-sysctl.rst
>+++ b/Documentation/networking/smc-sysctl.rst
>@@ -65,3 +65,9 @@ smcr_max_links_per_lgr - INTEGER
> 	for SMC-R v2.1 and later.
> 
> 	Default: 2
>+
>+smcr_max_conns_per_lgr - INTEGER
>+	Controls the max number of connections can be added to a SMC-R link group. The
>+	acceptable value ranges from 16 to 255. Only for SMC-R v2.1 and later.
>+
>+	Default: 255
>diff --git a/include/net/netns/smc.h b/include/net/netns/smc.h
>index da7023587824..fc752a50f91b 100644
>--- a/include/net/netns/smc.h
>+++ b/include/net/netns/smc.h
>@@ -23,5 +23,6 @@ struct netns_smc {
> 	int				sysctl_wmem;
> 	int				sysctl_rmem;
> 	int				sysctl_max_links_per_lgr;
>+	int				sysctl_max_conns_per_lgr;
> };
> #endif
>diff --git a/net/smc/smc_clc.c b/net/smc/smc_clc.c
>index 1f87c8895a27..0fda5156eef0 100644
>--- a/net/smc/smc_clc.c
>+++ b/net/smc/smc_clc.c
>@@ -944,7 +944,7 @@ int smc_clc_send_proposal(struct smc_sock *smc, struct smc_init_info *ini)
> 	}
> 	if (smcr_indicated(ini->smc_type_v2)) {
> 		memcpy(v2_ext->roce, ini->smcrv2.ib_gid_v2, SMC_GID_SIZE);
>-		v2_ext->max_conns = SMC_CONN_PER_LGR_PREFER;
>+		v2_ext->max_conns = net->smc.sysctl_max_conns_per_lgr;
> 		v2_ext->max_links = net->smc.sysctl_max_links_per_lgr;
> 	}
> 
>@@ -1191,7 +1191,8 @@ int smc_clc_srv_v2x_features_validate(struct smc_sock *smc,
> 		return SMC_CLC_DECL_NOV2EXT;
> 
> 	if (ini->smcr_version & SMC_V2) {
>-		ini->max_conns = min_t(u8, pclc_v2_ext->max_conns, SMC_CONN_PER_LGR_PREFER);
>+		ini->max_conns = min_t(u8, pclc_v2_ext->max_conns,
>+				       net->smc.sysctl_max_conns_per_lgr);
> 		if (ini->max_conns < SMC_CONN_PER_LGR_MIN)
> 			return SMC_CLC_DECL_MAXCONNERR;
> 
>diff --git a/net/smc/smc_sysctl.c b/net/smc/smc_sysctl.c
>index 3e9bb921e40a..a5946d1b9d60 100644
>--- a/net/smc/smc_sysctl.c
>+++ b/net/smc/smc_sysctl.c
>@@ -27,6 +27,8 @@ static const int net_smc_wmem_init = (64 * 1024);
> static const int net_smc_rmem_init = (64 * 1024);
> static int links_per_lgr_min = SMC_LINKS_ADD_LNK_MIN;
> static int links_per_lgr_max = SMC_LINKS_ADD_LNK_MAX;
>+static int conns_per_lgr_min = SMC_CONN_PER_LGR_MIN;
>+static int conns_per_lgr_max = SMC_CONN_PER_LGR_MAX;
> 
> static struct ctl_table smc_table[] = {
> 	{
>@@ -79,6 +81,15 @@ static struct ctl_table smc_table[] = {
> 		.extra1		= &links_per_lgr_min,
> 		.extra2		= &links_per_lgr_max,
> 	},
>+	{
>+		.procname	= "smcr_max_conns_per_lgr",
>+		.data		= &init_net.smc.sysctl_max_conns_per_lgr,
>+		.maxlen		= sizeof(int),
>+		.mode		= 0644,
>+		.proc_handler	= proc_dointvec_minmax,
>+		.extra1		= &conns_per_lgr_min,
>+		.extra2		= &conns_per_lgr_max,
>+	},
> 	{  }
> };
> 
>@@ -109,6 +120,7 @@ int __net_init smc_sysctl_net_init(struct net *net)
> 	WRITE_ONCE(net->smc.sysctl_wmem, net_smc_wmem_init);
> 	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;
> 
> 	return 0;
> 
>diff --git a/net/smc/smc_sysctl.h b/net/smc/smc_sysctl.h
>index 5783dd7575dd..eb2465ae1e15 100644
>--- a/net/smc/smc_sysctl.h
>+++ b/net/smc/smc_sysctl.h
>@@ -24,6 +24,7 @@ static inline int smc_sysctl_net_init(struct net *net)
> {
> 	net->smc.sysctl_autocorking_size = SMC_AUTOCORKING_DEFAULT_SIZE;
> 	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;
> 	return 0;
> }
> 
>-- 
>2.24.3 (Apple Git-128)