On Tue, Sep 20, 2022 at 10:53:54AM +0800, Wen Gu wrote: > SMC-R tests the viability of link by sending out TEST_LINK LLC > messages over RoCE fabric when connections on link have been > idle for a time longer than keepalive interval (testlink time). > > But using tcp_keepalive_time as testlink time maybe not quite > suitable because it is default no less than two hours[1], which > is too long for single link to find peer dead. The active host > will still use peer-dead link (QP) sending messages, and can't > find out until get IB_WC_RETRY_EXC_ERR error CQEs, which takes > more time than TEST_LINK timeout (SMC_LLC_WAIT_TIME) normally. > > So this patch introduces a independent sysctl for SMC-R to set > link keepalive time, in order to detect link down in time. The > default value is 30 seconds. > > [1] https://www.rfc-editor.org/rfc/rfc1122#page-101 > > Signed-off-by: Wen Gu <guwen@xxxxxxxxxxxxxxxxx> LGTM. Reviewed-by: Tony Lu <tonylu@xxxxxxxxxxxxxxxxx> > --- > Documentation/networking/smc-sysctl.rst | 7 +++++++ > include/net/netns/smc.h | 1 + > net/smc/smc_llc.c | 2 +- > net/smc/smc_llc.h | 1 + > net/smc/smc_sysctl.c | 14 ++++++++++++++ > 5 files changed, 24 insertions(+), 1 deletion(-) > > diff --git a/Documentation/networking/smc-sysctl.rst b/Documentation/networking/smc-sysctl.rst > index 742e90e..f8c3d59 100644 > --- a/Documentation/networking/smc-sysctl.rst > +++ b/Documentation/networking/smc-sysctl.rst > @@ -34,3 +34,10 @@ smcr_buf_type - INTEGER > - 1 - Use virtually contiguous buffers > - 2 - Mixed use of the two types. Try physically contiguous buffers first. > If not available, use virtually contiguous buffers then. > + > +smcr_testlink_time - INTEGER > + How frequently SMC-R link sends out TEST_LINK LLC messages to confirm > + viability, after the last activity of connections on it. The maximum > + value is (INT_MAX / HZ) seconds, the minimum value is 1 second. > + > + Default: 30 seconds. > diff --git a/include/net/netns/smc.h b/include/net/netns/smc.h > index 2adbe2b..d295e2c 100644 > --- a/include/net/netns/smc.h > +++ b/include/net/netns/smc.h > @@ -19,5 +19,6 @@ struct netns_smc { > #endif > unsigned int sysctl_autocorking_size; > unsigned int sysctl_smcr_buf_type; > + int sysctl_smcr_testlink_time; > }; > #endif > diff --git a/net/smc/smc_llc.c b/net/smc/smc_llc.c > index 175026a..388bd2e 100644 > --- a/net/smc/smc_llc.c > +++ b/net/smc/smc_llc.c > @@ -2127,7 +2127,7 @@ void smc_llc_lgr_init(struct smc_link_group *lgr, struct smc_sock *smc) > init_waitqueue_head(&lgr->llc_flow_waiter); > init_waitqueue_head(&lgr->llc_msg_waiter); > mutex_init(&lgr->llc_conf_mutex); > - lgr->llc_testlink_time = READ_ONCE(net->ipv4.sysctl_tcp_keepalive_time); > + lgr->llc_testlink_time = READ_ONCE(net->smc.sysctl_smcr_testlink_time) * HZ; > } > > /* called after lgr was removed from lgr_list */ > diff --git a/net/smc/smc_llc.h b/net/smc/smc_llc.h > index 4404e52..1de9a29 100644 > --- a/net/smc/smc_llc.h > +++ b/net/smc/smc_llc.h > @@ -19,6 +19,7 @@ > > #define SMC_LLC_WAIT_FIRST_TIME (5 * HZ) > #define SMC_LLC_WAIT_TIME (2 * HZ) > +#define SMC_LLC_TESTLINK_DEFAULT_TIME 30 > > enum smc_llc_reqresp { > SMC_LLC_REQ, > diff --git a/net/smc/smc_sysctl.c b/net/smc/smc_sysctl.c > index 0613868..7f68520 100644 > --- a/net/smc/smc_sysctl.c > +++ b/net/smc/smc_sysctl.c > @@ -16,8 +16,12 @@ > > #include "smc.h" > #include "smc_core.h" > +#include "smc_llc.h" > #include "smc_sysctl.h" > > +static int smcr_testlink_time_min = 1; > +static int smcr_testlink_time_max = (INT_MAX / HZ); > + > static struct ctl_table smc_table[] = { > { > .procname = "autocorking_size", > @@ -35,6 +39,15 @@ > .extra1 = SYSCTL_ZERO, > .extra2 = SYSCTL_TWO, > }, > + { > + .procname = "smcr_testlink_time", > + .data = &init_net.smc.sysctl_smcr_testlink_time, > + .maxlen = sizeof(int), > + .mode = 0644, > + .proc_handler = proc_dointvec_minmax, > + .extra1 = &smcr_testlink_time_min, > + .extra2 = &smcr_testlink_time_max, > + }, > { } > }; > > @@ -60,6 +73,7 @@ int __net_init smc_sysctl_net_init(struct net *net) > > net->smc.sysctl_autocorking_size = SMC_AUTOCORKING_DEFAULT_SIZE; > net->smc.sysctl_smcr_buf_type = SMCR_PHYS_CONT_BUFS; > + net->smc.sysctl_smcr_testlink_time = SMC_LLC_TESTLINK_DEFAULT_TIME; > > return 0; > > -- > 1.8.3.1
