From 0227f058aa29f5ab6f6ec79c3a36ae41f1e03a13 Mon Sep 17 00:00:00 2001
From: Tony Lu <tonylu@linux.alibaba.com>
Date: Tue, 20 Sep 2022 17:52:22 +0800
Subject: [PATCH] net/smc: Unbind r/w buffer size from clcsock and make them
tunable
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 <tonylu@linux.alibaba.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
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 45ba1522e189a..6d8acdbe9be1d 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 d295e2c10dcaf..582212ada3ba7 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 0939cc3b915af..e44ca7009632d 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 ebf56cdf17dbb..ea41f224f644f 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 3224d303cc9d4..b6f79fabb9d3f 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 @@ static struct ctl_table smc_table[] = {
.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;
--
GitLab