diff mbox series

[net-next,v3,1/3] net/smc: Make smc_tcp_listen_work() independent

Message ID 1d7365b47719546fe1f145affb01398d8287b381.1644041638.git.alibuda@linux.alibaba.com (mailing list archive)
State Not Applicable
Headers show
Series Optimizing performance in short-lived scenarios | expand

Commit Message

D. Wythe Feb. 5, 2022, 6:34 a.m. UTC 
From: "D. Wythe" <alibuda@linux.alibaba.com>

In multithread and 10K connections benchmark, the backend TCP connection
established very slowly, and lots of TCP connections stay in SYN_SENT
state.

Client: smc_run wrk -c 10000 -t 4 http://server

the netstate of server host shows like:
    145042 times the listen queue of a socket overflowed
    145042 SYNs to LISTEN sockets dropped

One reason of this issue is that, since the smc_tcp_listen_work() shared
the same workqueue (smc_hs_wq) with smc_listen_work(), while the
smc_listen_work() do blocking wait for smc connection established. Once
the workqueue became congested, it's will block the accept() from TCP
listen.

This patch creates a independent workqueue(smc_tcp_ls_wq) for
smc_tcp_listen_work(), separate it from smc_listen_work(), which is
quite acceptable considering that smc_tcp_listen_work() runs very fast.

Signed-off-by: D. Wythe <alibuda@linux.alibaba.com>
---
 net/smc/af_smc.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

Comments

kernel test robot Feb. 5, 2022, 12:16 p.m. UTC | #1 
Hi Wythe",

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on net-next/master]

url:    https://github.com/0day-ci/linux/commits/D-Wythe/Optimizing-performance-in-short-lived-scenarios/20220205-143638
base:   https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git c78b8b20e34920231eda02fb40c7aca7d88be837
config: x86_64-randconfig-s021 (https://download.01.org/0day-ci/archive/20220205/202202052019.I6XO0mge-lkp@intel.com/config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce:
        # apt-get install sparse
        # sparse version: v0.6.4-dirty
        # https://github.com/0day-ci/linux/commit/c750e361a42f2d32b4e041edfd0b51d9020a936c
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review D-Wythe/Optimizing-performance-in-short-lived-scenarios/20220205-143638
        git checkout c750e361a42f2d32b4e041edfd0b51d9020a936c
        # save the config file to linux build tree
        mkdir build_dir
        make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=x86_64 SHELL=/bin/bash net/smc/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>


sparse warnings: (new ones prefixed by >>)
>> net/smc/af_smc.c:62:25: sparse: sparse: symbol 'smc_tcp_ls_wq' was not declared. Should it be static?

Please review and possibly fold the followup patch.

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
diff mbox series

Patch

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index d5ea62b..1b40304 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -59,6 +59,7 @@ 
 						 * creation on client
 						 */
 
+struct workqueue_struct	*smc_tcp_ls_wq;	/* wq for tcp listen work */
 struct workqueue_struct	*smc_hs_wq;	/* wq for handshake work */
 struct workqueue_struct	*smc_close_wq;	/* wq for close work */
 
@@ -2124,7 +2125,7 @@  static void smc_clcsock_data_ready(struct sock *listen_clcsock)
 	lsmc->clcsk_data_ready(listen_clcsock);
 	if (lsmc->sk.sk_state == SMC_LISTEN) {
 		sock_hold(&lsmc->sk); /* sock_put in smc_tcp_listen_work() */
-		if (!queue_work(smc_hs_wq, &lsmc->tcp_listen_work))
+		if (!queue_work(smc_tcp_ls_wq, &lsmc->tcp_listen_work))
 			sock_put(&lsmc->sk);
 	}
 }
@@ -2919,9 +2920,14 @@  static int __init smc_init(void)
 		goto out_nl;
 
 	rc = -ENOMEM;
+
+	smc_tcp_ls_wq = alloc_workqueue("smc_tcp_ls_wq", 0, 0);
+	if (!smc_tcp_ls_wq)
+		goto out_pnet;
+
 	smc_hs_wq = alloc_workqueue("smc_hs_wq", 0, 0);
 	if (!smc_hs_wq)
-		goto out_pnet;
+		goto out_alloc_tcp_ls_wq;
 
 	smc_close_wq = alloc_workqueue("smc_close_wq", 0, 0);
 	if (!smc_close_wq)
@@ -2992,6 +2998,8 @@  static int __init smc_init(void)
 	destroy_workqueue(smc_close_wq);
 out_alloc_hs_wq:
 	destroy_workqueue(smc_hs_wq);
+out_alloc_tcp_ls_wq:
+	destroy_workqueue(smc_tcp_ls_wq);
 out_pnet:
 	smc_pnet_exit();
 out_nl:
@@ -3010,6 +3018,7 @@  static void __exit smc_exit(void)
 	smc_core_exit();
 	smc_ib_unregister_client();
 	destroy_workqueue(smc_close_wq);
+	destroy_workqueue(smc_tcp_ls_wq);
 	destroy_workqueue(smc_hs_wq);
 	proto_unregister(&smc_proto6);
 	proto_unregister(&smc_proto);