SMC shares some sysctls with TCP, but considering the difference
between these two protocols, it may not be very suitable for SMC
to reuse TCP parameter settings in some cases, such as keepalive
time or buffer size.
So this patch set aims to introduce some SMC specific sysctls to
independently and flexibly set the parameters that suit SMC.
v2->v1:
- Use proc_dointvec_jiffies as proc_handler and allow value 0 to
disable TEST_LINK.
Tony Lu (1):
net/smc: Unbind r/w buffer size from clcsock and make them tunable
Wen Gu (1):
net/smc: Introduce a specific sysctl for TEST_LINK time
Documentation/networking/smc-sysctl.rst | 25 +++++++++++++++++++++++++
include/net/netns/smc.h | 3 +++
net/smc/af_smc.c | 5 ++---
net/smc/smc_core.c | 8 ++++----
net/smc/smc_llc.c | 2 +-
net/smc/smc_llc.h | 1 +
net/smc/smc_sysctl.c | 30 ++++++++++++++++++++++++++++++
7 files changed, 66 insertions(+), 8 deletions(-)
--
1.8.3.1
From: Tony Lu <[email protected]>
Currently, SMC uses smc->sk.sk_{rcv|snd}buf to create buffers for
send buffer and RMB. And the values of buffer size are from tcp_{w|r}mem
in clcsock.
The buffer size from TCP socket doesn't fit SMC well. Generally, buffers
are usually larger than TCP for SMC-R/-D to get higher performance, for
they are different underlay devices and paths.
So this patch unbinds buffer size from TCP, and introduces two sysctl
knobs to tune them independently. Also, these knobs are per net
namespace and work for containers.
Signed-off-by: Tony Lu <[email protected]>
---
Documentation/networking/smc-sysctl.rst | 18 ++++++++++++++++++
include/net/netns/smc.h | 2 ++
net/smc/af_smc.c | 5 ++---
net/smc/smc_core.c | 8 ++++----
net/smc/smc_sysctl.c | 21 +++++++++++++++++++++
5 files changed, 47 insertions(+), 7 deletions(-)
diff --git a/Documentation/networking/smc-sysctl.rst b/Documentation/networking/smc-sysctl.rst
index 45ba152..6d8acdb 100644
--- a/Documentation/networking/smc-sysctl.rst
+++ b/Documentation/networking/smc-sysctl.rst
@@ -41,3 +41,21 @@ smcr_testlink_time - INTEGER
disabling TEST_LINK.
Default: 30 seconds.
+
+wmem - INTEGER
+ Initial size of send buffer used by SMC sockets.
+ The default value inherits from net.ipv4.tcp_wmem[1].
+
+ The minimum value is 16KiB and there is no hard limit for max value, but
+ only allowed 512KiB for SMC-R and 1MiB for SMC-D.
+
+ Default: 16K
+
+rmem - INTEGER
+ Initial size of receive buffer (RMB) used by SMC sockets.
+ The default value inherits from net.ipv4.tcp_rmem[1].
+
+ The minimum value is 16KiB and there is no hard limit for max value, but
+ only allowed 512KiB for SMC-R and 1MiB for SMC-D.
+
+ Default: 128K
diff --git a/include/net/netns/smc.h b/include/net/netns/smc.h
index d295e2c..582212a 100644
--- a/include/net/netns/smc.h
+++ b/include/net/netns/smc.h
@@ -20,5 +20,7 @@ struct netns_smc {
unsigned int sysctl_autocorking_size;
unsigned int sysctl_smcr_buf_type;
int sysctl_smcr_testlink_time;
+ int sysctl_wmem;
+ int sysctl_rmem;
};
#endif
diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index 0939cc3..e44ca70 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -379,6 +379,8 @@ static struct sock *smc_sock_alloc(struct net *net, struct socket *sock,
sk->sk_state = SMC_INIT;
sk->sk_destruct = smc_destruct;
sk->sk_protocol = protocol;
+ WRITE_ONCE(sk->sk_sndbuf, READ_ONCE(net->smc.sysctl_wmem));
+ WRITE_ONCE(sk->sk_rcvbuf, READ_ONCE(net->smc.sysctl_rmem));
smc = smc_sk(sk);
INIT_WORK(&smc->tcp_listen_work, smc_tcp_listen_work);
INIT_WORK(&smc->connect_work, smc_connect_work);
@@ -3253,9 +3255,6 @@ static int __smc_create(struct net *net, struct socket *sock, int protocol,
smc->clcsock = clcsock;
}
- smc->sk.sk_sndbuf = max(smc->clcsock->sk->sk_sndbuf, SMC_BUF_MIN_SIZE);
- smc->sk.sk_rcvbuf = max(smc->clcsock->sk->sk_rcvbuf, SMC_BUF_MIN_SIZE);
-
out:
return rc;
}
diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
index ebf56cd..ea41f22 100644
--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -2307,10 +2307,10 @@ static int __smc_buf_create(struct smc_sock *smc, bool is_smcd, bool is_rmb)
if (is_rmb)
/* use socket recv buffer size (w/o overhead) as start value */
- sk_buf_size = smc->sk.sk_rcvbuf / 2;
+ sk_buf_size = smc->sk.sk_rcvbuf;
else
/* use socket send buffer size (w/o overhead) as start value */
- sk_buf_size = smc->sk.sk_sndbuf / 2;
+ sk_buf_size = smc->sk.sk_sndbuf;
for (bufsize_short = smc_compress_bufsize(sk_buf_size, is_smcd, is_rmb);
bufsize_short >= 0; bufsize_short--) {
@@ -2369,7 +2369,7 @@ static int __smc_buf_create(struct smc_sock *smc, bool is_smcd, bool is_rmb)
if (is_rmb) {
conn->rmb_desc = buf_desc;
conn->rmbe_size_short = bufsize_short;
- smc->sk.sk_rcvbuf = bufsize * 2;
+ smc->sk.sk_rcvbuf = bufsize;
atomic_set(&conn->bytes_to_rcv, 0);
conn->rmbe_update_limit =
smc_rmb_wnd_update_limit(buf_desc->len);
@@ -2377,7 +2377,7 @@ static int __smc_buf_create(struct smc_sock *smc, bool is_smcd, bool is_rmb)
smc_ism_set_conn(conn); /* map RMB/smcd_dev to conn */
} else {
conn->sndbuf_desc = buf_desc;
- smc->sk.sk_sndbuf = bufsize * 2;
+ smc->sk.sk_sndbuf = bufsize;
atomic_set(&conn->sndbuf_space, bufsize);
}
return 0;
diff --git a/net/smc/smc_sysctl.c b/net/smc/smc_sysctl.c
index 3224d30..b6f79fa 100644
--- a/net/smc/smc_sysctl.c
+++ b/net/smc/smc_sysctl.c
@@ -19,6 +19,9 @@
#include "smc_llc.h"
#include "smc_sysctl.h"
+static int min_sndbuf = SMC_BUF_MIN_SIZE;
+static int min_rcvbuf = SMC_BUF_MIN_SIZE;
+
static struct ctl_table smc_table[] = {
{
.procname = "autocorking_size",
@@ -43,6 +46,22 @@
.mode = 0644,
.proc_handler = proc_dointvec_jiffies,
},
+ {
+ .procname = "wmem",
+ .data = &init_net.smc.sysctl_wmem,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &min_sndbuf,
+ },
+ {
+ .procname = "rmem",
+ .data = &init_net.smc.sysctl_rmem,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &min_rcvbuf,
+ },
{ }
};
@@ -69,6 +88,8 @@ 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;
+ WRITE_ONCE(net->smc.sysctl_wmem, READ_ONCE(net->ipv4.sysctl_tcp_wmem[1]));
+ WRITE_ONCE(net->smc.sysctl_rmem, READ_ONCE(net->ipv4.sysctl_tcp_rmem[1]));
return 0;
--
1.8.3.1
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 <[email protected]>
---
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 --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;
--
1.8.3.1
On 20.09.22 11:52, Wen Gu wrote:
> SMC shares some sysctls with TCP, but considering the difference
> between these two protocols, it may not be very suitable for SMC
> to reuse TCP parameter settings in some cases, such as keepalive
> time or buffer size.
>
> So this patch set aims to introduce some SMC specific sysctls to
> independently and flexibly set the parameters that suit SMC.
>
> v2->v1:
> - Use proc_dointvec_jiffies as proc_handler and allow value 0 to
> disable TEST_LINK.
>
> Tony Lu (1):
> net/smc: Unbind r/w buffer size from clcsock and make them tunable
>
> Wen Gu (1):
> net/smc: Introduce a specific sysctl for TEST_LINK time
>
> Documentation/networking/smc-sysctl.rst | 25 +++++++++++++++++++++++++
> include/net/netns/smc.h | 3 +++
> net/smc/af_smc.c | 5 ++---
> net/smc/smc_core.c | 8 ++++----
> net/smc/smc_llc.c | 2 +-
> net/smc/smc_llc.h | 1 +
> net/smc/smc_sysctl.c | 30 ++++++++++++++++++++++++++++++
> 7 files changed, 66 insertions(+), 8 deletions(-)
>
Looks good. Thank you!
For the series:
Acked-by: Wenjia Zhang <[email protected]>
Hello:
This series was applied to netdev/net-next.git (master)
by Paolo Abeni <[email protected]>:
On Tue, 20 Sep 2022 17:52:20 +0800 you wrote:
> SMC shares some sysctls with TCP, but considering the difference
> between these two protocols, it may not be very suitable for SMC
> to reuse TCP parameter settings in some cases, such as keepalive
> time or buffer size.
>
> So this patch set aims to introduce some SMC specific sysctls to
> independently and flexibly set the parameters that suit SMC.
>
> [...]
Here is the summary with links:
- [net-next,v2,1/2] net/smc: Introduce a specific sysctl for TEST_LINK time
https://git.kernel.org/netdev/net-next/c/77eee3251431
- [net-next,v2,2/2] net/smc: Unbind r/w buffer size from clcsock and make them tunable
https://git.kernel.org/netdev/net-next/c/0227f058aa29
You are awesome, thank you!
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