LVS
lvs-devel
Google
 
Web LinuxVirtualServer.org

Re: [PATCH] ipvs: improved SH fallback strategy

To: Alexander Frolkin <avf@xxxxxxxxxxxxxx>
Subject: Re: [PATCH] ipvs: improved SH fallback strategy
Cc: Julian Anastasov <ja@xxxxxx>, lvs-devel@xxxxxxxxxxxxxxx, Wensong Zhang <wensong@xxxxxxxxxxxx>, Simon Horman <horms@xxxxxxxxxxxx>, netdev@xxxxxxxxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx
From: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>
Date: Mon, 23 Sep 2013 23:42:50 +0400
Hello.

On 09/23/2013 03:51 PM, Alexander Frolkin wrote:

Improve the SH fallback realserver selection strategy.

With sh and sh-fallback, if a realserver is down, this attempts to
distribute the traffic that would have gone to that server evenly
among the remaining servers.

Signed-off-by: Alexander Frolkin <avf@xxxxxxxxxxxxxx>
---
diff --git a/net/netfilter/ipvs/ip_vs_sh.c b/net/netfilter/ipvs/ip_vs_sh.c
index f16c027..1676354 100644
--- a/net/netfilter/ipvs/ip_vs_sh.c
+++ b/net/netfilter/ipvs/ip_vs_sh.c
@@ -120,22 +120,35 @@ static inline struct ip_vs_dest *
  ip_vs_sh_get_fallback(struct ip_vs_service *svc, struct ip_vs_sh_state *s,
                      const union nf_inet_addr *addr, __be16 port)
  {
-       unsigned int offset;
-       unsigned int hash;
+       unsigned int offset, roffset;
+       unsigned int hash, ihash;
        struct ip_vs_dest *dest;

-       for (offset = 0; offset < IP_VS_SH_TAB_SIZE; offset++) {
-               hash = ip_vs_sh_hashkey(svc->af, addr, port, offset);
-               dest = rcu_dereference(s->buckets[hash].dest);
-               if (!dest)
-                       break;
-               if (is_unavailable(dest))
-                       IP_VS_DBG_BUF(6, "SH: selected unavailable server "
-                                     "%s:%d (offset %d)",
+       ihash = ip_vs_sh_hashkey(svc->af, addr, port, 0);
+       dest = rcu_dereference(s->buckets[ihash].dest);
+

   Empty line net needed here (and it wasn't there in the original code).

+       if (!dest)
+               return NULL;
+

   Here too.

+       if (is_unavailable(dest)) {
+               IP_VS_DBG_BUF(6, "SH: selected unavailable server "
+                     "%s:%d, reselecting",
+                     IP_VS_DBG_ADDR(svc->af, &dest->addr),
+                     ntohs(dest->port));
+               for (offset = 0; offset < IP_VS_SH_TAB_SIZE; offset++) {
+                       roffset = (offset + ihash) % IP_VS_SH_TAB_SIZE;
+                       hash = ip_vs_sh_hashkey(svc->af, addr, port, roffset);
+                       dest = rcu_dereference(s->buckets[hash].dest);
+                       if (is_unavailable(dest))
+                               IP_VS_DBG_BUF(6, "SH: selected unavailable "
+                                     "server %s:%d (offset %d), reselecting",
                                      IP_VS_DBG_ADDR(svc->af, &dest->addr),

WBR, Sergei

--
To unsubscribe from this list: send the line "unsubscribe lvs-devel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html

<Prev in Thread] Current Thread [Next in Thread>