ipv4: Namespaceify tcp_max_syn_backlog knob

Different namespace application might require different maximal
number of remembered connection requests.

Signed-off-by: Haishuang Yan <yanhaishuang@cmss.chinamobile.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 2 deletions

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 56b5f49e3f97..7e4be4f361f3 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -2419,7 +2419,7 @@ static void __net_exit tcp_sk_exit(struct net *net)
 
 static int __net_init tcp_sk_init(struct net *net)
 {
-        int res, cpu;
+        int res, cpu, cnt;
 
         net->ipv4.tcp_sk = alloc_percpu(struct sock *);
         if (!net->ipv4.tcp_sk)
@@ -2458,10 +2458,13 @@ static int __net_init tcp_sk_init(struct net *net)
         net->ipv4.sysctl_tcp_notsent_lowat = UINT_MAX;
         net->ipv4.sysctl_tcp_tw_reuse = 0;
 
+        cnt = tcp_hashinfo.ehash_mask + 1;
         net->ipv4.tcp_death_row.sysctl_tw_recycle = 0;
-        net->ipv4.tcp_death_row.sysctl_max_tw_buckets = (tcp_hashinfo.ehash_mask + 1) / 2;
+        net->ipv4.tcp_death_row.sysctl_max_tw_buckets = (cnt + 1) / 2;
         net->ipv4.tcp_death_row.hashinfo = &tcp_hashinfo;
 
+        net->ipv4.sysctl_max_syn_backlog = max(128, cnt / 256);
+
         return 0;
 fail:
         tcp_sk_exit(net);