Re: [PATCH] ipvs: improved SH fallback strategy
From: Sergei Shtylyov <hidden>
Date: 2013-09-23 19:42:54
Also in:
lkml, lvs-devel
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.
quoted hunk ↗ jump to hunk
Signed-off-by: Alexander Frolkin <redacted> ---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