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

From: Dust Li
Date: Fri Nov 24 2023 - 00:51:05 EST


On Wed, Nov 22, 2023 at 09:52:57PM +0800, Guangguan Wang wrote:
>Add a new sysctl: net.smc.smcr_max_links_per_lgr, which is
>used to control the preferred max links per lgr for SMC-R
>v2.1. The default value of this sysctl is 2, and the acceptable
>value ranges from 1 to 2.
>
>Signed-off-by: Guangguan Wang <guangguan.wang@xxxxxxxxxxxxxxxxx>

LGTM

Reviewed-by: Dust Li <dust.li@xxxxxxxxxxxxxxxxx>

>---
> Documentation/networking/smc-sysctl.rst | 8 ++++++++
> include/net/netns/smc.h | 1 +
> net/smc/af_smc.c | 2 +-
> net/smc/smc_clc.c | 10 +++++++---
> net/smc/smc_clc.h | 3 ++-
> net/smc/smc_sysctl.c | 12 ++++++++++++
> net/smc/smc_sysctl.h | 1 +
> 7 files changed, 32 insertions(+), 5 deletions(-)
>
>diff --git a/Documentation/networking/smc-sysctl.rst b/Documentation/networking/smc-sysctl.rst
>index 769149d98773..c6ef86ef4c4f 100644
>--- a/Documentation/networking/smc-sysctl.rst
>+++ b/Documentation/networking/smc-sysctl.rst
>@@ -57,3 +57,11 @@ rmem - INTEGER
> only allowed 512KiB for SMC-R and 1MiB for SMC-D.
>
> Default: 64KiB
>+
>+smcr_max_links_per_lgr - INTEGER
>+ Controls the max number of links can be added to a SMC-R link group. Notice that
>+ the actual number of the links added to a SMC-R link group depends on the number
>+ of RDMA devices exist in the system. The acceptable value ranges from 1 to 2. Only
>+ for SMC-R v2.1 and later.
>+
>+ Default: 2
>diff --git a/include/net/netns/smc.h b/include/net/netns/smc.h
>index 582212ada3ba..da7023587824 100644
>--- a/include/net/netns/smc.h
>+++ b/include/net/netns/smc.h
>@@ -22,5 +22,6 @@ struct netns_smc {
> int sysctl_smcr_testlink_time;
> int sysctl_wmem;
> int sysctl_rmem;
>+ int sysctl_max_links_per_lgr;
> };
> #endif
>diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
>index da97f946b79b..f8da484efe90 100644
>--- a/net/smc/af_smc.c
>+++ b/net/smc/af_smc.c
>@@ -2457,7 +2457,7 @@ static void smc_listen_work(struct work_struct *work)
> if (rc)
> goto out_decl;
>
>- rc = smc_clc_srv_v2x_features_validate(pclc, ini);
>+ rc = smc_clc_srv_v2x_features_validate(new_smc, pclc, ini);
> if (rc)
> goto out_decl;
>
>diff --git a/net/smc/smc_clc.c b/net/smc/smc_clc.c
>index 8deb46c28f1d..1f87c8895a27 100644
>--- a/net/smc/smc_clc.c
>+++ b/net/smc/smc_clc.c
>@@ -824,6 +824,7 @@ int smc_clc_send_proposal(struct smc_sock *smc, struct smc_init_info *ini)
> struct smc_clc_smcd_gid_chid *gidchids;
> struct smc_clc_msg_proposal_area *pclc;
> struct smc_clc_ipv6_prefix *ipv6_prfx;
>+ struct net *net = sock_net(&smc->sk);
> struct smc_clc_v2_extension *v2_ext;
> struct smc_clc_msg_smcd *pclc_smcd;
> struct smc_clc_msg_trail *trl;
>@@ -944,7 +945,7 @@ 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_links = SMC_LINKS_PER_LGR_MAX_PREFER;
>+ v2_ext->max_links = net->smc.sysctl_max_links_per_lgr;
> }
>
> pclc_base->hdr.length = htons(plen);
>@@ -1171,10 +1172,12 @@ int smc_clc_send_accept(struct smc_sock *new_smc, bool srv_first_contact,
> return len > 0 ? 0 : len;
> }
>
>-int smc_clc_srv_v2x_features_validate(struct smc_clc_msg_proposal *pclc,
>+int smc_clc_srv_v2x_features_validate(struct smc_sock *smc,
>+ struct smc_clc_msg_proposal *pclc,
> struct smc_init_info *ini)
> {
> struct smc_clc_v2_extension *pclc_v2_ext;
>+ struct net *net = sock_net(&smc->sk);
>
> ini->max_conns = SMC_CONN_PER_LGR_MAX;
> ini->max_links = SMC_LINKS_ADD_LNK_MAX;
>@@ -1192,7 +1195,8 @@ int smc_clc_srv_v2x_features_validate(struct smc_clc_msg_proposal *pclc,
> if (ini->max_conns < SMC_CONN_PER_LGR_MIN)
> return SMC_CLC_DECL_MAXCONNERR;
>
>- ini->max_links = min_t(u8, pclc_v2_ext->max_links, SMC_LINKS_PER_LGR_MAX_PREFER);
>+ ini->max_links = min_t(u8, pclc_v2_ext->max_links,
>+ net->smc.sysctl_max_links_per_lgr);
> if (ini->max_links < SMC_LINKS_ADD_LNK_MIN)
> return SMC_CLC_DECL_MAXLINKERR;
> }
>diff --git a/net/smc/smc_clc.h b/net/smc/smc_clc.h
>index c5c8e7db775a..89b258cedffe 100644
>--- a/net/smc/smc_clc.h
>+++ b/net/smc/smc_clc.h
>@@ -422,7 +422,8 @@ int smc_clc_send_confirm(struct smc_sock *smc, bool clnt_first_contact,
> u8 version, u8 *eid, struct smc_init_info *ini);
> int smc_clc_send_accept(struct smc_sock *smc, bool srv_first_contact,
> u8 version, u8 *negotiated_eid, struct smc_init_info *ini);
>-int smc_clc_srv_v2x_features_validate(struct smc_clc_msg_proposal *pclc,
>+int smc_clc_srv_v2x_features_validate(struct smc_sock *smc,
>+ struct smc_clc_msg_proposal *pclc,
> struct smc_init_info *ini);
> int smc_clc_clnt_v2x_features_validate(struct smc_clc_first_contact_ext *fce,
> struct smc_init_info *ini);
>diff --git a/net/smc/smc_sysctl.c b/net/smc/smc_sysctl.c
>index 5cbc18c6e62b..3e9bb921e40a 100644
>--- a/net/smc/smc_sysctl.c
>+++ b/net/smc/smc_sysctl.c
>@@ -25,6 +25,8 @@ static int max_sndbuf = INT_MAX / 2;
> static int max_rcvbuf = INT_MAX / 2;
> 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 struct ctl_table smc_table[] = {
> {
>@@ -68,6 +70,15 @@ static struct ctl_table smc_table[] = {
> .extra1 = &min_rcvbuf,
> .extra2 = &max_rcvbuf,
> },
>+ {
>+ .procname = "smcr_max_links_per_lgr",
>+ .data = &init_net.smc.sysctl_max_links_per_lgr,
>+ .maxlen = sizeof(int),
>+ .mode = 0644,
>+ .proc_handler = proc_dointvec_minmax,
>+ .extra1 = &links_per_lgr_min,
>+ .extra2 = &links_per_lgr_max,
>+ },
> { }
> };
>
>@@ -97,6 +108,7 @@ int __net_init smc_sysctl_net_init(struct net *net)
> net->smc.sysctl_smcr_testlink_time = SMC_LLC_TESTLINK_DEFAULT_TIME;
> 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;
>
> return 0;
>
>diff --git a/net/smc/smc_sysctl.h b/net/smc/smc_sysctl.h
>index 0becc11bd2f4..5783dd7575dd 100644
>--- a/net/smc/smc_sysctl.h
>+++ b/net/smc/smc_sysctl.h
>@@ -23,6 +23,7 @@ void __net_exit smc_sysctl_net_exit(struct net *net);
> 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;
> return 0;
> }
>
>--
>2.24.3 (Apple Git-128)