diff mbox series

[net-next,3/7] net/smc: add sysctl for autocorking

Message ID 20220301094402.14992-4-dust.li@linux.alibaba.com (mailing list archive)
State Not Applicable
Headers show
Series net/smc: some datapath performance optimizations | expand

Commit Message

Dust Li March 1, 2022, 9:43 a.m. UTC 
This add a new sysctl: net.smc.autocorking_size

We can dynamically change the behaviour of autocorking
by change the value of autocorking_size.
Setting to 0 disables autocorking in SMC

Signed-off-by: Dust Li <dust.li@linux.alibaba.com>
---
 Documentation/networking/smc-sysctl.rst | 23 +++++++++++++++++++++++
 include/net/netns/smc.h                 |  1 +
 net/smc/smc_sysctl.c                    | 10 ++++++++++
 net/smc/smc_tx.c                        |  2 +-
 4 files changed, 35 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/networking/smc-sysctl.rst

Comments

Jakub Kicinski March 1, 2022, 10:20 p.m. UTC | #1 
On Tue,  1 Mar 2022 17:43:58 +0800 Dust Li wrote:
> --- a/net/smc/smc_tx.c
> +++ b/net/smc/smc_tx.c
> @@ -147,7 +147,7 @@ static bool smc_should_autocork(struct smc_sock *smc)
>  	struct smc_connection *conn = &smc->conn;
>  	int corking_size;
>  
> -	corking_size = min(SMC_AUTOCORKING_DEFAULT_SIZE,
> +	corking_size = min(sock_net(&smc->sk)->smc.sysctl_autocorking_size,
>  			   conn->sndbuf_desc->len >> 1);

I think this broke the build:

In file included from ../include/linux/kernel.h:26,
                 from ../include/linux/random.h:11,
                 from ../include/linux/net.h:18,
                 from ../net/smc/smc_tx.c:16:
../net/smc/smc_tx.c: In function ‘smc_should_autocork’:
../include/linux/minmax.h:20:35: error: comparison of distinct pointer types lacks a cast [-Werror]
   20 |         (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
      |                                   ^~
../include/linux/minmax.h:26:18: note: in expansion of macro ‘__typecheck’
   26 |                 (__typecheck(x, y) && __no_side_effects(x, y))
      |                  ^~~~~~~~~~~
../include/linux/minmax.h:36:31: note: in expansion of macro ‘__safe_cmp’
   36 |         __builtin_choose_expr(__safe_cmp(x, y), \
      |                               ^~~~~~~~~~
../include/linux/minmax.h:45:25: note: in expansion of macro ‘__careful_cmp’
   45 | #define min(x, y)       __careful_cmp(x, y, <)
      |                         ^~~~~~~~~~~~~
../net/smc/smc_tx.c:150:24: note: in expansion of macro ‘min’
  150 |         corking_size = min(sock_net(&smc->sk)->smc.sysctl_autocorking_size,
      |                        ^~~
diff mbox series

Patch

diff --git a/Documentation/networking/smc-sysctl.rst b/Documentation/networking/smc-sysctl.rst
new file mode 100644
index 000000000000..c53f8c61c9e4
--- /dev/null
+++ b/Documentation/networking/smc-sysctl.rst
@@ -0,0 +1,23 @@ 
+.. SPDX-License-Identifier: GPL-2.0
+
+=========
+SMC Sysctl
+=========
+
+/proc/sys/net/smc/* Variables
+==============================
+
+autocorking_size - INTEGER
+	Setting SMC auto corking size:
+	SMC auto corking is like TCP auto corking from the application's
+	perspective of view. When applications do consecutive small
+	write()/sendmsg() system calls, we try to coalesce these small writes
+	as much as possible, to lower total amount of CDC and RDMA Write been
+	sent.
+	autocorking_size limits the maximum corked bytes that can be sent to
+	the under device in 1 single sending. If set to 0, the SMC auto corking
+	is disabled.
+	Applications can still use TCP_CORK for optimal behavior when they
+	know how/when to uncork their sockets.
+
+	Default: 64K
diff --git a/include/net/netns/smc.h b/include/net/netns/smc.h
index 1682eae50579..e5389eeaf8bd 100644
--- a/include/net/netns/smc.h
+++ b/include/net/netns/smc.h
@@ -17,5 +17,6 @@  struct netns_smc {
 #ifdef CONFIG_SYSCTL
 	struct ctl_table_header		*smc_hdr;
 #endif
+	unsigned int			sysctl_autocorking_size;
 };
 #endif
diff --git a/net/smc/smc_sysctl.c b/net/smc/smc_sysctl.c
index 8a3a8e145976..3b59876aaac9 100644
--- a/net/smc/smc_sysctl.c
+++ b/net/smc/smc_sysctl.c
@@ -14,9 +14,17 @@ 
 #include <linux/sysctl.h>
 #include <net/net_namespace.h>
 
+#include "smc.h"
 #include "smc_sysctl.h"
 
 static struct ctl_table smc_table[] = {
+	{
+		.procname       = "autocorking_size",
+		.data           = &init_net.smc.sysctl_autocorking_size,
+		.maxlen         = sizeof(unsigned int),
+		.mode           = 0644,
+		.proc_handler	= proc_douintvec,
+	},
 	{  }
 };
 
@@ -40,6 +48,8 @@  static __net_init int smc_sysctl_init_net(struct net *net)
 	if (!net->smc.smc_hdr)
 		goto err_reg;
 
+	net->smc.sysctl_autocorking_size = SMC_AUTOCORKING_DEFAULT_SIZE;
+
 	return 0;
 
 err_reg:
diff --git a/net/smc/smc_tx.c b/net/smc/smc_tx.c
index 062c6b1535e3..257dc0d0aeb1 100644
--- a/net/smc/smc_tx.c
+++ b/net/smc/smc_tx.c
@@ -147,7 +147,7 @@  static bool smc_should_autocork(struct smc_sock *smc)
 	struct smc_connection *conn = &smc->conn;
 	int corking_size;
 
-	corking_size = min(SMC_AUTOCORKING_DEFAULT_SIZE,
+	corking_size = min(sock_net(&smc->sk)->smc.sysctl_autocorking_size,
 			   conn->sndbuf_desc->len >> 1);
 
 	if (atomic_read(&conn->cdc_pend_tx_wr) == 0 ||