diff mbox series

[net-next,v2,1/2] net/smc: Introduce a specific sysctl for TEST_LINK time

Message ID 1663667542-119851-2-git-send-email-guwen@linux.alibaba.com (mailing list archive)
State Accepted
Commit 77eee32514314209961af5c2982e871ecb364445
Delegated to: Netdev Maintainers
Headers show
Series Separate SMC parameter settings from TCP sysctls | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 4577 this patch: 4577
netdev/cc_maintainers warning 5 maintainers not CCed: tonylu@linux.alibaba.com alibuda@linux.alibaba.com linux-doc@vger.kernel.org corbet@lwn.net dust.li@linux.alibaba.com
netdev/build_clang success Errors and warnings before: 1109 this patch: 1109
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 4764 this patch: 4764
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 58 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Wen Gu Sept. 20, 2022, 9:52 a.m. UTC
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@linux.alibaba.com>
---
 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                    | 9 +++++++++
 5 files changed, 19 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/Documentation/networking/smc-sysctl.rst b/Documentation/networking/smc-sysctl.rst
index 742e90e..45ba152 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. Value 0 means
+	disabling TEST_LINK.
+
+	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..524649d 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);
 }
 
 /* called after lgr was removed from lgr_list */
diff --git a/net/smc/smc_llc.h b/net/smc/smc_llc.h
index 4404e52..7e7a316 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 * HZ)
 
 enum smc_llc_reqresp {
 	SMC_LLC_REQ,
diff --git a/net/smc/smc_sysctl.c b/net/smc/smc_sysctl.c
index 0613868..3224d30 100644
--- a/net/smc/smc_sysctl.c
+++ b/net/smc/smc_sysctl.c
@@ -16,6 +16,7 @@ 
 
 #include "smc.h"
 #include "smc_core.h"
+#include "smc_llc.h"
 #include "smc_sysctl.h"
 
 static struct ctl_table smc_table[] = {
@@ -35,6 +36,13 @@ 
 		.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_jiffies,
+	},
 	{  }
 };
 
@@ -60,6 +68,7 @@  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;