| 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 |
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 --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 ||
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