[PATCH net-next] ipvs: add sync_persist_mode flag

[Julian Anastasov <ja@xxxxxx>]

Add sync_persist_mode flag to reduce sync traffic
by syncing only persistent templates.

Signed-off-by: Julian Anastasov <ja@xxxxxx>
Tested-by: Aleksey Chudov <aleksey.chudov@xxxxxxxxx>
---
 Documentation/networking/ipvs-sysctl.txt |   13 +++++++++++++
 include/net/ip_vs.h                      |   11 +++++++++++
 net/netfilter/ipvs/ip_vs_ctl.c           |    7 +++++++
 net/netfilter/ipvs/ip_vs_sync.c          |   12 ++++++++++++
 4 files changed, 43 insertions(+), 0 deletions(-)

diff --git a/Documentation/networking/ipvs-sysctl.txt 
b/Documentation/networking/ipvs-sysctl.txt
index 9573d0c..7a3c047 100644
--- a/Documentation/networking/ipvs-sysctl.txt
+++ b/Documentation/networking/ipvs-sysctl.txt
@@ -181,6 +181,19 @@ snat_reroute - BOOLEAN
        always be the same as the original route so it is an optimisation
        to disable snat_reroute and avoid the recalculation.
 
+sync_persist_mode - INTEGER
+       default 0
+
+       Controls the synchronisation of connections when using persistence
+
+       0: All types of connections are synchronised
+       1: Attempt to reduce the synchronisation traffic depending on
+       the connection type. For persistent services avoid synchronisation
+       for normal connections, do it only for persistence templates.
+       In such case, for TCP and SCTP it may need enabling sloppy_tcp and
+       sloppy_sctp flags on backup servers. For non-persistent services
+       such optimization is not applied, mode 0 is assumed.
+
 sync_version - INTEGER
        default 1
 
diff --git a/include/net/ip_vs.h b/include/net/ip_vs.h
index e667df1..f0d70f0 100644
--- a/include/net/ip_vs.h
+++ b/include/net/ip_vs.h
@@ -975,6 +975,7 @@ struct netns_ipvs {
        int                     sysctl_snat_reroute;
        int                     sysctl_sync_ver;
        int                     sysctl_sync_ports;
+       int                     sysctl_sync_persist_mode;
        unsigned long           sysctl_sync_qlen_max;
        int                     sysctl_sync_sock_size;
        int                     sysctl_cache_bypass;
@@ -1076,6 +1077,11 @@ static inline int sysctl_sync_ports(struct netns_ipvs 
*ipvs)
        return ACCESS_ONCE(ipvs->sysctl_sync_ports);
 }
 
+static inline int sysctl_sync_persist_mode(struct netns_ipvs *ipvs)
+{
+       return ipvs->sysctl_sync_persist_mode;
+}
+
 static inline unsigned long sysctl_sync_qlen_max(struct netns_ipvs *ipvs)
 {
        return ipvs->sysctl_sync_qlen_max;
@@ -1139,6 +1145,11 @@ static inline int sysctl_sync_ports(struct netns_ipvs 
*ipvs)
        return 1;
 }
 
+static inline int sysctl_sync_persist_mode(struct netns_ipvs *ipvs)
+{
+       return 0;
+}
+
 static inline unsigned long sysctl_sync_qlen_max(struct netns_ipvs *ipvs)
 {
        return IPVS_SYNC_QLEN_MAX;
diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
index 1b14abb..0c129cc 100644
--- a/net/netfilter/ipvs/ip_vs_ctl.c
+++ b/net/netfilter/ipvs/ip_vs_ctl.c
@@ -1715,6 +1715,12 @@ static struct ctl_table vs_vars[] = {
                .proc_handler   = &proc_do_sync_ports,
        },
        {
+               .procname       = "sync_persist_mode",
+               .maxlen         = sizeof(int),
+               .mode           = 0644,
+               .proc_handler   = proc_dointvec,
+       },
+       {
                .procname       = "sync_qlen_max",
                .maxlen         = sizeof(unsigned long),
                .mode           = 0644,
@@ -3728,6 +3734,7 @@ static int __net_init 
ip_vs_control_net_init_sysctl(struct net *net)
        tbl[idx++].data = &ipvs->sysctl_sync_ver;
        ipvs->sysctl_sync_ports = 1;
        tbl[idx++].data = &ipvs->sysctl_sync_ports;
+       tbl[idx++].data = &ipvs->sysctl_sync_persist_mode;
        ipvs->sysctl_sync_qlen_max = nr_free_buffer_pages() / 32;
        tbl[idx++].data = &ipvs->sysctl_sync_qlen_max;
        ipvs->sysctl_sync_sock_size = 0;
diff --git a/net/netfilter/ipvs/ip_vs_sync.c b/net/netfilter/ipvs/ip_vs_sync.c
index 2fc6639..03c43c0 100644
--- a/net/netfilter/ipvs/ip_vs_sync.c
+++ b/net/netfilter/ipvs/ip_vs_sync.c
@@ -425,6 +425,16 @@ ip_vs_sync_buff_create_v0(struct netns_ipvs *ipvs)
        return sb;
 }
 
+/* Check if connection is controlled by persistence */
+static inline bool in_persistence(struct ip_vs_conn *cp)
+{
+       for (cp = cp->control; cp; cp = cp->control) {
+               if (cp->flags & IP_VS_CONN_F_TEMPLATE)
+                       return true;
+       }
+       return false;
+}
+
 /* Check if conn should be synced.
  * pkts: conn packets, use sysctl_sync_threshold to avoid packet check
  * - (1) sync_refresh_period: reduce sync rate. Additionally, retry
@@ -447,6 +457,8 @@ static int ip_vs_sync_conn_needed(struct netns_ipvs *ipvs,
        /* Check if we sync in current state */
        if (unlikely(cp->flags & IP_VS_CONN_F_TEMPLATE))
                force = 0;
+       else if (unlikely(sysctl_sync_persist_mode(ipvs) && in_persistence(cp)))
+               return 0;
        else if (likely(cp->protocol == IPPROTO_TCP)) {
                if (!((1 << cp->state) &
                      ((1 << IP_VS_TCP_S_ESTABLISHED) |
-- 
1.7.3.4

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