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Date: Wed, 6 Mar 2013 10:42:18 +0200
From: Julian Anastasov <ja@....bg>
To: Simon Horman <horms@...ge.net.au>
Cc: lvs-devel@...r.kernel.org, netdev@...r.kernel.org
Subject: [PATCH net-next 08/12] ipvs: remove rs_lock by using RCU
rs_lock was used to protect rs_table (hash table)
from updaters (under global mutex) and readers (packet handlers).
We can remove rs_lock by using RCU lock for readers. Reclaiming
dest only with kfree_rcu is enough because the readers access
only fields from the ip_vs_dest structure.
Use hlist for rs_table.
As we are now using hlist_del_rcu, introduce in_rs_table
flag as replacement for the list_empty checks which do not
work with RCU. It is needed because only NAT dests are in
the rs_table.
Signed-off-by: Julian Anastasov <ja@....bg>
---
include/net/ip_vs.h | 14 ++++---
net/netfilter/ipvs/ip_vs_core.c | 5 +--
net/netfilter/ipvs/ip_vs_ctl.c | 74 ++++++++++++++-------------------------
3 files changed, 36 insertions(+), 57 deletions(-)
diff --git a/include/net/ip_vs.h b/include/net/ip_vs.h
index f0038a8..b2657c1 100644
--- a/include/net/ip_vs.h
+++ b/include/net/ip_vs.h
@@ -738,7 +738,7 @@ struct ip_vs_dest_dst {
*/
struct ip_vs_dest {
struct list_head n_list; /* for the dests in the service */
- struct list_head d_list; /* for table with all the dests */
+ struct hlist_node d_list; /* for table with all the dests */
u16 af; /* address family */
__be16 port; /* port number of the server */
@@ -767,6 +767,9 @@ struct ip_vs_dest {
__be16 vport; /* virtual port number */
union nf_inet_addr vaddr; /* virtual IP address */
__u32 vfwmark; /* firewall mark of service */
+
+ struct rcu_head rcu_head;
+ unsigned int in_rs_table:1; /* we are in rs_table */
};
@@ -897,7 +900,7 @@ struct netns_ipvs {
#define IP_VS_RTAB_SIZE (1 << IP_VS_RTAB_BITS)
#define IP_VS_RTAB_MASK (IP_VS_RTAB_SIZE - 1)
- struct list_head rs_table[IP_VS_RTAB_SIZE];
+ struct hlist_head rs_table[IP_VS_RTAB_SIZE];
/* ip_vs_app */
struct list_head app_list;
/* ip_vs_proto */
@@ -933,7 +936,6 @@ struct netns_ipvs {
int num_services; /* no of virtual services */
- rwlock_t rs_lock; /* real services table */
/* Trash for destinations */
struct list_head dest_trash;
/* Service counters */
@@ -1364,9 +1366,9 @@ static inline void ip_vs_service_put(struct ip_vs_service *svc)
atomic_dec(&svc->usecnt);
}
-extern struct ip_vs_dest *
-ip_vs_lookup_real_service(struct net *net, int af, __u16 protocol,
- const union nf_inet_addr *daddr, __be16 dport);
+extern bool
+ip_vs_has_real_service(struct net *net, int af, __u16 protocol,
+ const union nf_inet_addr *daddr, __be16 dport);
extern int ip_vs_use_count_inc(void);
extern void ip_vs_use_count_dec(void);
diff --git a/net/netfilter/ipvs/ip_vs_core.c b/net/netfilter/ipvs/ip_vs_core.c
index 7e03f42..2ea2862 100644
--- a/net/netfilter/ipvs/ip_vs_core.c
+++ b/net/netfilter/ipvs/ip_vs_core.c
@@ -1164,9 +1164,8 @@ ip_vs_out(unsigned int hooknum, struct sk_buff *skb, int af)
sizeof(_ports), _ports, &iph);
if (pptr == NULL)
return NF_ACCEPT; /* Not for me */
- if (ip_vs_lookup_real_service(net, af, iph.protocol,
- &iph.saddr,
- pptr[0])) {
+ if (ip_vs_has_real_service(net, af, iph.protocol, &iph.saddr,
+ pptr[0])) {
/*
* Notify the real server: there is no
* existing entry if it is not RST
diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
index 844fb9b..f4b53c4 100644
--- a/net/netfilter/ipvs/ip_vs_ctl.c
+++ b/net/netfilter/ipvs/ip_vs_ctl.c
@@ -506,17 +506,13 @@ static inline unsigned int ip_vs_rs_hashkey(int af,
& IP_VS_RTAB_MASK;
}
-/*
- * Hashes ip_vs_dest in rs_table by <proto,addr,port>.
- * should be called with locked tables.
- */
-static int ip_vs_rs_hash(struct netns_ipvs *ipvs, struct ip_vs_dest *dest)
+/* Hash ip_vs_dest in rs_table by <proto,addr,port>. */
+static void ip_vs_rs_hash(struct netns_ipvs *ipvs, struct ip_vs_dest *dest)
{
unsigned int hash;
- if (!list_empty(&dest->d_list)) {
- return 0;
- }
+ if (dest->in_rs_table)
+ return;
/*
* Hash by proto,addr,port,
@@ -524,34 +520,25 @@ static int ip_vs_rs_hash(struct netns_ipvs *ipvs, struct ip_vs_dest *dest)
*/
hash = ip_vs_rs_hashkey(dest->af, &dest->addr, dest->port);
- list_add(&dest->d_list, &ipvs->rs_table[hash]);
-
- return 1;
+ hlist_add_head_rcu(&dest->d_list, &ipvs->rs_table[hash]);
+ dest->in_rs_table = 1;
}
-/*
- * UNhashes ip_vs_dest from rs_table.
- * should be called with locked tables.
- */
-static int ip_vs_rs_unhash(struct ip_vs_dest *dest)
+/* Unhash ip_vs_dest from rs_table. */
+static void ip_vs_rs_unhash(struct ip_vs_dest *dest)
{
/*
* Remove it from the rs_table table.
*/
- if (!list_empty(&dest->d_list)) {
- list_del_init(&dest->d_list);
+ if (dest->in_rs_table) {
+ hlist_del_rcu(&dest->d_list);
+ dest->in_rs_table = 0;
}
-
- return 1;
}
-/*
- * Lookup real service by <proto,addr,port> in the real service table.
- */
-struct ip_vs_dest *
-ip_vs_lookup_real_service(struct net *net, int af, __u16 protocol,
- const union nf_inet_addr *daddr,
- __be16 dport)
+/* Check if real service by <proto,addr,port> is present */
+bool ip_vs_has_real_service(struct net *net, int af, __u16 protocol,
+ const union nf_inet_addr *daddr, __be16 dport)
{
struct netns_ipvs *ipvs = net_ipvs(net);
unsigned int hash;
@@ -563,21 +550,21 @@ ip_vs_lookup_real_service(struct net *net, int af, __u16 protocol,
*/
hash = ip_vs_rs_hashkey(af, daddr, dport);
- read_lock(&ipvs->rs_lock);
- list_for_each_entry(dest, &ipvs->rs_table[hash], d_list) {
+ rcu_read_lock();
+ hlist_for_each_entry_rcu(dest, &ipvs->rs_table[hash], d_list) {
if ((dest->af == af)
&& ip_vs_addr_equal(af, &dest->addr, daddr)
&& (dest->port == dport)
&& ((dest->protocol == protocol) ||
dest->vfwmark)) {
/* HIT */
- read_unlock(&ipvs->rs_lock);
- return dest;
+ rcu_read_unlock();
+ return true;
}
}
- read_unlock(&ipvs->rs_lock);
+ rcu_read_unlock();
- return NULL;
+ return false;
}
/*
@@ -610,9 +597,6 @@ ip_vs_lookup_dest(struct ip_vs_service *svc, const union nf_inet_addr *daddr,
* the backup synchronization daemon. It finds the
* destination to be bound to the received connection
* on the backup.
- *
- * ip_vs_lookup_real_service() looked promissing, but
- * seems not working as expected.
*/
struct ip_vs_dest *ip_vs_find_dest(struct net *net, int af,
const union nf_inet_addr *daddr,
@@ -712,7 +696,7 @@ ip_vs_trash_get_dest(struct ip_vs_service *svc, const union nf_inet_addr *daddr,
__ip_vs_dst_cache_reset(dest);
__ip_vs_unbind_svc(dest);
free_percpu(dest->stats.cpustats);
- kfree(dest);
+ kfree_rcu(dest, rcu_head);
}
}
@@ -739,7 +723,7 @@ static void ip_vs_trash_cleanup(struct net *net)
__ip_vs_dst_cache_reset(dest);
__ip_vs_unbind_svc(dest);
free_percpu(dest->stats.cpustats);
- kfree(dest);
+ kfree_rcu(dest, rcu_head);
}
}
@@ -804,9 +788,7 @@ __ip_vs_update_dest(struct ip_vs_service *svc, struct ip_vs_dest *dest,
* Put the real service in rs_table if not present.
* For now only for NAT!
*/
- write_lock_bh(&ipvs->rs_lock);
ip_vs_rs_hash(ipvs, dest);
- write_unlock_bh(&ipvs->rs_lock);
}
atomic_set(&dest->conn_flags, conn_flags);
@@ -902,7 +884,7 @@ ip_vs_new_dest(struct ip_vs_service *svc, struct ip_vs_dest_user_kern *udest,
atomic_set(&dest->persistconns, 0);
atomic_set(&dest->refcnt, 1);
- INIT_LIST_HEAD(&dest->d_list);
+ INIT_HLIST_NODE(&dest->d_list);
spin_lock_init(&dest->dst_lock);
spin_lock_init(&dest->stats.lock);
__ip_vs_update_dest(svc, dest, udest, 1);
@@ -1042,9 +1024,7 @@ static void __ip_vs_del_dest(struct net *net, struct ip_vs_dest *dest)
/*
* Remove it from the d-linked list with the real services.
*/
- write_lock_bh(&ipvs->rs_lock);
ip_vs_rs_unhash(dest);
- write_unlock_bh(&ipvs->rs_lock);
/*
* Decrease the refcnt of the dest, and free the dest
@@ -1064,7 +1044,7 @@ static void __ip_vs_del_dest(struct net *net, struct ip_vs_dest *dest)
time, so the operation here is OK */
atomic_dec(&dest->svc->refcnt);
free_percpu(dest->stats.cpustats);
- kfree(dest);
+ kfree_rcu(dest, rcu_head);
} else {
IP_VS_DBG_BUF(3, "Moving dest %s:%u into trash, "
"dest->refcnt=%d\n",
@@ -3801,11 +3781,9 @@ int __net_init ip_vs_control_net_init(struct net *net)
int idx;
struct netns_ipvs *ipvs = net_ipvs(net);
- rwlock_init(&ipvs->rs_lock);
-
/* Initialize rs_table */
for (idx = 0; idx < IP_VS_RTAB_SIZE; idx++)
- INIT_LIST_HEAD(&ipvs->rs_table[idx]);
+ INIT_HLIST_HEAD(&ipvs->rs_table[idx]);
INIT_LIST_HEAD(&ipvs->dest_trash);
atomic_set(&ipvs->ftpsvc_counter, 0);
@@ -3882,7 +3860,7 @@ int __init ip_vs_control_init(void)
EnterFunction(2);
- /* Initialize svc_table, ip_vs_svc_fwm_table, rs_table */
+ /* Initialize svc_table, ip_vs_svc_fwm_table */
for (idx = 0; idx < IP_VS_SVC_TAB_SIZE; idx++) {
INIT_LIST_HEAD(&ip_vs_svc_table[idx]);
INIT_LIST_HEAD(&ip_vs_svc_fwm_table[idx]);
--
1.7.3.4
--
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