diff mbox series

[net-next] net/smc: Clear memory when release and reuse buffer

Message ID 20211203113331.2818873-1-kgraul@linux.ibm.com (mailing list archive)
State Accepted
Commit 1c5526968e270e4efccfa1da21d211a4915cdeda
Delegated to: Netdev Maintainers
Headers show
Series [net-next] net/smc: Clear memory when release and reuse buffer | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Single patches do not need cover letters
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers warning 9 maintainers not CCed: bpf@vger.kernel.org kafai@fb.com daniel@iogearbox.net songliubraving@fb.com kpsingh@kernel.org john.fastabend@gmail.com yhs@fb.com ast@kernel.org andrii@kernel.org
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 34 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Karsten Graul Dec. 3, 2021, 11:33 a.m. UTC 
From: Tony Lu <tonylu@linux.alibaba.com>

Currently, buffers are cleared when smc connections are created and
buffers are reused. This slows down the speed of establishing new
connections. In most cases, the applications want to establish
connections as quickly as possible.

This patch moves memset() from connection creation path to release and
buffer unuse path, this trades off between speed of establishing and
release.

Test environments:
- CPU Intel Xeon Platinum 8 core, mem 32 GiB, nic Mellanox CX4
- socket sndbuf / rcvbuf: 16384 / 131072 bytes
- w/o first round, 5 rounds, avg, 100 conns batch per round
- smc_buf_create() use bpftrace kprobe, introduces extra latency

Latency benchmarks for smc_buf_create():
  w/o patch : 19040.0 ns
  w/  patch :  1932.6 ns
  ratio :        10.2% (-89.8%)

Latency benchmarks for socket create and connect:
  w/o patch :   143.3 us
  w/  patch :   102.2 us
  ratio :        71.3% (-28.7%)

The latency of establishing connections is reduced by 28.7%.

Signed-off-by: Tony Lu <tonylu@linux.alibaba.com>
Reviewed-by: Wen Gu <guwen@linux.alibaba.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
---
 net/smc/smc_core.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

Comments

patchwork-bot+netdevbpf@kernel.org Dec. 7, 2021, 1:10 a.m. UTC | #1 
Hello:

This patch was applied to netdev/net-next.git (master)
by Jakub Kicinski <kuba@kernel.org>:

On Fri,  3 Dec 2021 12:33:31 +0100 you wrote:
> From: Tony Lu <tonylu@linux.alibaba.com>
> 
> Currently, buffers are cleared when smc connections are created and
> buffers are reused. This slows down the speed of establishing new
> connections. In most cases, the applications want to establish
> connections as quickly as possible.
> 
> [...]

Here is the summary with links:
  - [net-next] net/smc: Clear memory when release and reuse buffer
    https://git.kernel.org/netdev/net-next/c/1c5526968e27

You are awesome, thank you!
diff mbox series

Patch

diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
index 387d28b2f8dd..85be94cabb01 100644
--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -1101,18 +1101,24 @@  static void smcr_buf_unuse(struct smc_buf_desc *rmb_desc,
 		smc_buf_free(lgr, true, rmb_desc);
 	} else {
 		rmb_desc->used = 0;
+		memset(rmb_desc->cpu_addr, 0, rmb_desc->len);
 	}
 }
 
 static void smc_buf_unuse(struct smc_connection *conn,
 			  struct smc_link_group *lgr)
 {
-	if (conn->sndbuf_desc)
+	if (conn->sndbuf_desc) {
 		conn->sndbuf_desc->used = 0;
-	if (conn->rmb_desc && lgr->is_smcd)
+		memset(conn->sndbuf_desc->cpu_addr, 0, conn->sndbuf_desc->len);
+	}
+	if (conn->rmb_desc && lgr->is_smcd) {
 		conn->rmb_desc->used = 0;
-	else if (conn->rmb_desc)
+		memset(conn->rmb_desc->cpu_addr, 0, conn->rmb_desc->len +
+		       sizeof(struct smcd_cdc_msg));
+	} else if (conn->rmb_desc) {
 		smcr_buf_unuse(conn->rmb_desc, lgr);
+	}
 }
 
 /* remove a finished connection from its link group */
@@ -2148,7 +2154,6 @@  static int __smc_buf_create(struct smc_sock *smc, bool is_smcd, bool is_rmb)
 		if (buf_desc) {
 			SMC_STAT_RMB_SIZE(smc, is_smcd, is_rmb, bufsize);
 			SMC_STAT_BUF_REUSE(smc, is_smcd, is_rmb);
-			memset(buf_desc->cpu_addr, 0, bufsize);
 			break; /* found reusable slot */
 		}