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authorEric Dumazet <edumazet@google.com>2014-10-27 21:45:24 -0700
committerDavid S. Miller <davem@davemloft.net>2014-10-29 15:05:15 -0400
commitdca145ffaa8d39ea1904491ac81b92b7049372c0 (patch)
treeebe67ece694b9e54281047a6037b7d5776f9f56b /net/ipv4
parent7aef06db0f91c7b48305d07b62edf43179adb28c (diff)
downloadop-kernel-dev-dca145ffaa8d39ea1904491ac81b92b7049372c0.zip
op-kernel-dev-dca145ffaa8d39ea1904491ac81b92b7049372c0.tar.gz
tcp: allow for bigger reordering level
While testing upcoming Yaogong patch (converting out of order queue into an RB tree), I hit the max reordering level of linux TCP stack. Reordering level was limited to 127 for no good reason, and some network setups [1] can easily reach this limit and get limited throughput. Allow a new max limit of 300, and add a sysctl to allow admins to even allow bigger (or lower) values if needed. [1] Aggregation of links, per packet load balancing, fabrics not doing deep packet inspections, alternative TCP congestion modules... Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Yaogong Wang <wygivan@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4')
-rw-r--r--net/ipv4/sysctl_net_ipv4.c7
-rw-r--r--net/ipv4/tcp_input.c3
2 files changed, 9 insertions, 1 deletions
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index b3c53c8..e0ee384 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -496,6 +496,13 @@ static struct ctl_table ipv4_table[] = {
.proc_handler = proc_dointvec
},
{
+ .procname = "tcp_max_reordering",
+ .data = &sysctl_tcp_max_reordering,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec
+ },
+ {
.procname = "tcp_dsack",
.data = &sysctl_tcp_dsack,
.maxlen = sizeof(int),
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index a12b455..9a18cdd 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -81,6 +81,7 @@ int sysctl_tcp_window_scaling __read_mostly = 1;
int sysctl_tcp_sack __read_mostly = 1;
int sysctl_tcp_fack __read_mostly = 1;
int sysctl_tcp_reordering __read_mostly = TCP_FASTRETRANS_THRESH;
+int sysctl_tcp_max_reordering __read_mostly = 300;
EXPORT_SYMBOL(sysctl_tcp_reordering);
int sysctl_tcp_dsack __read_mostly = 1;
int sysctl_tcp_app_win __read_mostly = 31;
@@ -833,7 +834,7 @@ static void tcp_update_reordering(struct sock *sk, const int metric,
if (metric > tp->reordering) {
int mib_idx;
- tp->reordering = min(TCP_MAX_REORDERING, metric);
+ tp->reordering = min(sysctl_tcp_max_reordering, metric);
/* This exciting event is worth to be remembered. 8) */
if (ts)
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