Commit 12bbb0d1 authored by Dust Li's avatar Dust Li Committed by David S. Miller
Browse files

net/smc: add sysctl for autocorking 



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: default avatarDust Li <dust.li@linux.alibaba.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent dcd2cf5f

Documentation/networking/smc-sysctl.rst

0 → 100644
+23 −0
Original line number Diff line number Diff line 
.. 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

include/net/netns/smc.h

+1 −0
Original line number Diff line number Diff line
@@ -17,5 +17,6 @@ struct netns_smc { 
#ifdef CONFIG_SYSCTL

	struct ctl_table_header		*smc_hdr;

#endif

	unsigned int			sysctl_autocorking_size;

};

#endif

net/smc/smc_sysctl.c

+10 −0
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@@ -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:

net/smc/smc_tx.c

+1 −1
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@@ -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 ||