![Pavel Emelyanov](/assets/img/avatar_default.png)
In case we load lblc or lblcr module we can leak some sysctl tables if the call to register_ip_vs_scheduler() fails. I've looked at the register_ip_vs_scheduler() code and saw, that the only reason to fail is the name collision, so I think that with some 3rd party schedulers this becomes a relevant issue. No? Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Acked-by: Simon Horman <horms@verge.net.au> Signed-off-by: David S. Miller <davem@davemloft.net>
604 lines
14 KiB
C
604 lines
14 KiB
C
/*
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* IPVS: Locality-Based Least-Connection scheduling module
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*
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* Version: $Id: ip_vs_lblc.c,v 1.10 2002/09/15 08:14:08 wensong Exp $
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*
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* Authors: Wensong Zhang <wensong@gnuchina.org>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* Changes:
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* Martin Hamilton : fixed the terrible locking bugs
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* *lock(tbl->lock) ==> *lock(&tbl->lock)
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* Wensong Zhang : fixed the uninitilized tbl->lock bug
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* Wensong Zhang : added doing full expiration check to
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* collect stale entries of 24+ hours when
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* no partial expire check in a half hour
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* Julian Anastasov : replaced del_timer call with del_timer_sync
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* to avoid the possible race between timer
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* handler and del_timer thread in SMP
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*
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*/
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/*
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* The lblc algorithm is as follows (pseudo code):
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*
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* if cachenode[dest_ip] is null then
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* n, cachenode[dest_ip] <- {weighted least-conn node};
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* else
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* n <- cachenode[dest_ip];
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* if (n is dead) OR
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* (n.conns>n.weight AND
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* there is a node m with m.conns<m.weight/2) then
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* n, cachenode[dest_ip] <- {weighted least-conn node};
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*
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* return n;
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*
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* Thanks must go to Wenzhuo Zhang for talking WCCP to me and pushing
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* me to write this module.
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*/
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#include <linux/ip.h>
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/skbuff.h>
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#include <linux/jiffies.h>
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/* for sysctl */
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#include <linux/fs.h>
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#include <linux/sysctl.h>
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#include <net/ip_vs.h>
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/*
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* It is for garbage collection of stale IPVS lblc entries,
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* when the table is full.
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*/
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#define CHECK_EXPIRE_INTERVAL (60*HZ)
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#define ENTRY_TIMEOUT (6*60*HZ)
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/*
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* It is for full expiration check.
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* When there is no partial expiration check (garbage collection)
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* in a half hour, do a full expiration check to collect stale
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* entries that haven't been touched for a day.
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*/
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#define COUNT_FOR_FULL_EXPIRATION 30
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static int sysctl_ip_vs_lblc_expiration = 24*60*60*HZ;
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/*
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* for IPVS lblc entry hash table
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*/
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#ifndef CONFIG_IP_VS_LBLC_TAB_BITS
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#define CONFIG_IP_VS_LBLC_TAB_BITS 10
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#endif
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#define IP_VS_LBLC_TAB_BITS CONFIG_IP_VS_LBLC_TAB_BITS
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#define IP_VS_LBLC_TAB_SIZE (1 << IP_VS_LBLC_TAB_BITS)
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#define IP_VS_LBLC_TAB_MASK (IP_VS_LBLC_TAB_SIZE - 1)
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/*
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* IPVS lblc entry represents an association between destination
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* IP address and its destination server
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*/
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struct ip_vs_lblc_entry {
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struct list_head list;
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__be32 addr; /* destination IP address */
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struct ip_vs_dest *dest; /* real server (cache) */
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unsigned long lastuse; /* last used time */
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};
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/*
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* IPVS lblc hash table
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*/
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struct ip_vs_lblc_table {
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rwlock_t lock; /* lock for this table */
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struct list_head bucket[IP_VS_LBLC_TAB_SIZE]; /* hash bucket */
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atomic_t entries; /* number of entries */
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int max_size; /* maximum size of entries */
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struct timer_list periodic_timer; /* collect stale entries */
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int rover; /* rover for expire check */
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int counter; /* counter for no expire */
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};
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/*
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* IPVS LBLC sysctl table
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*/
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static ctl_table vs_vars_table[] = {
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{
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.procname = "lblc_expiration",
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.data = &sysctl_ip_vs_lblc_expiration,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = &proc_dointvec_jiffies,
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},
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{ .ctl_name = 0 }
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};
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static ctl_table vs_table[] = {
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{
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.procname = "vs",
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.mode = 0555,
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.child = vs_vars_table
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},
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{ .ctl_name = 0 }
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};
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static ctl_table ipvs_ipv4_table[] = {
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{
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.ctl_name = NET_IPV4,
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.procname = "ipv4",
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.mode = 0555,
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.child = vs_table
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},
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{ .ctl_name = 0 }
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};
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static ctl_table lblc_root_table[] = {
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{
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.ctl_name = CTL_NET,
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.procname = "net",
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.mode = 0555,
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.child = ipvs_ipv4_table
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},
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{ .ctl_name = 0 }
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};
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static struct ctl_table_header * sysctl_header;
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/*
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* new/free a ip_vs_lblc_entry, which is a mapping of a destionation
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* IP address to a server.
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*/
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static inline struct ip_vs_lblc_entry *
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ip_vs_lblc_new(__be32 daddr, struct ip_vs_dest *dest)
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{
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struct ip_vs_lblc_entry *en;
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en = kmalloc(sizeof(struct ip_vs_lblc_entry), GFP_ATOMIC);
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if (en == NULL) {
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IP_VS_ERR("ip_vs_lblc_new(): no memory\n");
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return NULL;
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}
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INIT_LIST_HEAD(&en->list);
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en->addr = daddr;
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atomic_inc(&dest->refcnt);
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en->dest = dest;
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return en;
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}
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static inline void ip_vs_lblc_free(struct ip_vs_lblc_entry *en)
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{
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list_del(&en->list);
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/*
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* We don't kfree dest because it is refered either by its service
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* or the trash dest list.
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*/
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atomic_dec(&en->dest->refcnt);
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kfree(en);
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}
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/*
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* Returns hash value for IPVS LBLC entry
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*/
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static inline unsigned ip_vs_lblc_hashkey(__be32 addr)
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{
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return (ntohl(addr)*2654435761UL) & IP_VS_LBLC_TAB_MASK;
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}
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/*
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* Hash an entry in the ip_vs_lblc_table.
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* returns bool success.
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*/
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static int
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ip_vs_lblc_hash(struct ip_vs_lblc_table *tbl, struct ip_vs_lblc_entry *en)
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{
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unsigned hash;
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if (!list_empty(&en->list)) {
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IP_VS_ERR("ip_vs_lblc_hash(): request for already hashed, "
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"called from %p\n", __builtin_return_address(0));
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return 0;
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}
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/*
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* Hash by destination IP address
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*/
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hash = ip_vs_lblc_hashkey(en->addr);
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write_lock(&tbl->lock);
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list_add(&en->list, &tbl->bucket[hash]);
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atomic_inc(&tbl->entries);
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write_unlock(&tbl->lock);
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return 1;
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}
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/*
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* Get ip_vs_lblc_entry associated with supplied parameters.
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*/
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static inline struct ip_vs_lblc_entry *
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ip_vs_lblc_get(struct ip_vs_lblc_table *tbl, __be32 addr)
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{
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unsigned hash;
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struct ip_vs_lblc_entry *en;
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hash = ip_vs_lblc_hashkey(addr);
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read_lock(&tbl->lock);
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list_for_each_entry(en, &tbl->bucket[hash], list) {
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if (en->addr == addr) {
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/* HIT */
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read_unlock(&tbl->lock);
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return en;
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}
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}
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read_unlock(&tbl->lock);
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return NULL;
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}
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/*
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* Flush all the entries of the specified table.
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*/
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static void ip_vs_lblc_flush(struct ip_vs_lblc_table *tbl)
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{
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int i;
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struct ip_vs_lblc_entry *en, *nxt;
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for (i=0; i<IP_VS_LBLC_TAB_SIZE; i++) {
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write_lock(&tbl->lock);
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list_for_each_entry_safe(en, nxt, &tbl->bucket[i], list) {
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ip_vs_lblc_free(en);
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atomic_dec(&tbl->entries);
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}
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write_unlock(&tbl->lock);
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}
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}
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static inline void ip_vs_lblc_full_check(struct ip_vs_lblc_table *tbl)
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{
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unsigned long now = jiffies;
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int i, j;
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struct ip_vs_lblc_entry *en, *nxt;
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for (i=0, j=tbl->rover; i<IP_VS_LBLC_TAB_SIZE; i++) {
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j = (j + 1) & IP_VS_LBLC_TAB_MASK;
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write_lock(&tbl->lock);
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list_for_each_entry_safe(en, nxt, &tbl->bucket[j], list) {
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if (time_before(now,
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en->lastuse + sysctl_ip_vs_lblc_expiration))
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continue;
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ip_vs_lblc_free(en);
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atomic_dec(&tbl->entries);
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}
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write_unlock(&tbl->lock);
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}
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tbl->rover = j;
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}
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/*
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* Periodical timer handler for IPVS lblc table
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* It is used to collect stale entries when the number of entries
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* exceeds the maximum size of the table.
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*
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* Fixme: we probably need more complicated algorithm to collect
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* entries that have not been used for a long time even
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* if the number of entries doesn't exceed the maximum size
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* of the table.
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* The full expiration check is for this purpose now.
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*/
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static void ip_vs_lblc_check_expire(unsigned long data)
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{
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struct ip_vs_lblc_table *tbl;
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unsigned long now = jiffies;
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int goal;
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int i, j;
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struct ip_vs_lblc_entry *en, *nxt;
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tbl = (struct ip_vs_lblc_table *)data;
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if ((tbl->counter % COUNT_FOR_FULL_EXPIRATION) == 0) {
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/* do full expiration check */
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ip_vs_lblc_full_check(tbl);
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tbl->counter = 1;
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goto out;
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}
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if (atomic_read(&tbl->entries) <= tbl->max_size) {
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tbl->counter++;
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goto out;
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}
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goal = (atomic_read(&tbl->entries) - tbl->max_size)*4/3;
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if (goal > tbl->max_size/2)
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goal = tbl->max_size/2;
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for (i=0, j=tbl->rover; i<IP_VS_LBLC_TAB_SIZE; i++) {
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j = (j + 1) & IP_VS_LBLC_TAB_MASK;
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write_lock(&tbl->lock);
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list_for_each_entry_safe(en, nxt, &tbl->bucket[j], list) {
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if (time_before(now, en->lastuse + ENTRY_TIMEOUT))
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continue;
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ip_vs_lblc_free(en);
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atomic_dec(&tbl->entries);
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goal--;
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}
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write_unlock(&tbl->lock);
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if (goal <= 0)
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break;
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}
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tbl->rover = j;
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out:
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mod_timer(&tbl->periodic_timer, jiffies+CHECK_EXPIRE_INTERVAL);
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}
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static int ip_vs_lblc_init_svc(struct ip_vs_service *svc)
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{
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int i;
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struct ip_vs_lblc_table *tbl;
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/*
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* Allocate the ip_vs_lblc_table for this service
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*/
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tbl = kmalloc(sizeof(struct ip_vs_lblc_table), GFP_ATOMIC);
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if (tbl == NULL) {
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IP_VS_ERR("ip_vs_lblc_init_svc(): no memory\n");
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return -ENOMEM;
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}
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svc->sched_data = tbl;
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IP_VS_DBG(6, "LBLC hash table (memory=%Zdbytes) allocated for "
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"current service\n",
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sizeof(struct ip_vs_lblc_table));
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/*
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* Initialize the hash buckets
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*/
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for (i=0; i<IP_VS_LBLC_TAB_SIZE; i++) {
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INIT_LIST_HEAD(&tbl->bucket[i]);
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}
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rwlock_init(&tbl->lock);
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tbl->max_size = IP_VS_LBLC_TAB_SIZE*16;
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tbl->rover = 0;
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tbl->counter = 1;
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/*
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* Hook periodic timer for garbage collection
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*/
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init_timer(&tbl->periodic_timer);
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tbl->periodic_timer.data = (unsigned long)tbl;
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tbl->periodic_timer.function = ip_vs_lblc_check_expire;
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tbl->periodic_timer.expires = jiffies+CHECK_EXPIRE_INTERVAL;
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add_timer(&tbl->periodic_timer);
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return 0;
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}
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static int ip_vs_lblc_done_svc(struct ip_vs_service *svc)
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{
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struct ip_vs_lblc_table *tbl = svc->sched_data;
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/* remove periodic timer */
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del_timer_sync(&tbl->periodic_timer);
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/* got to clean up table entries here */
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ip_vs_lblc_flush(tbl);
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/* release the table itself */
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kfree(svc->sched_data);
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IP_VS_DBG(6, "LBLC hash table (memory=%Zdbytes) released\n",
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sizeof(struct ip_vs_lblc_table));
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return 0;
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}
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static int ip_vs_lblc_update_svc(struct ip_vs_service *svc)
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{
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return 0;
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}
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static inline struct ip_vs_dest *
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__ip_vs_wlc_schedule(struct ip_vs_service *svc, struct iphdr *iph)
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{
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struct ip_vs_dest *dest, *least;
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int loh, doh;
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/*
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* We think the overhead of processing active connections is fifty
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* times higher than that of inactive connections in average. (This
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* fifty times might not be accurate, we will change it later.) We
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* use the following formula to estimate the overhead:
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* dest->activeconns*50 + dest->inactconns
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* and the load:
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* (dest overhead) / dest->weight
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*
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* Remember -- no floats in kernel mode!!!
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* The comparison of h1*w2 > h2*w1 is equivalent to that of
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* h1/w1 > h2/w2
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* if every weight is larger than zero.
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*
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* The server with weight=0 is quiesced and will not receive any
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* new connection.
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*/
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list_for_each_entry(dest, &svc->destinations, n_list) {
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if (dest->flags & IP_VS_DEST_F_OVERLOAD)
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continue;
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if (atomic_read(&dest->weight) > 0) {
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least = dest;
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loh = atomic_read(&least->activeconns) * 50
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+ atomic_read(&least->inactconns);
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goto nextstage;
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}
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}
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return NULL;
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/*
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* Find the destination with the least load.
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*/
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nextstage:
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list_for_each_entry_continue(dest, &svc->destinations, n_list) {
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if (dest->flags & IP_VS_DEST_F_OVERLOAD)
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continue;
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doh = atomic_read(&dest->activeconns) * 50
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+ atomic_read(&dest->inactconns);
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if (loh * atomic_read(&dest->weight) >
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doh * atomic_read(&least->weight)) {
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least = dest;
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loh = doh;
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}
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}
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IP_VS_DBG(6, "LBLC: server %d.%d.%d.%d:%d "
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"activeconns %d refcnt %d weight %d overhead %d\n",
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NIPQUAD(least->addr), ntohs(least->port),
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atomic_read(&least->activeconns),
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atomic_read(&least->refcnt),
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atomic_read(&least->weight), loh);
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return least;
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}
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/*
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* If this destination server is overloaded and there is a less loaded
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* server, then return true.
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*/
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static inline int
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is_overloaded(struct ip_vs_dest *dest, struct ip_vs_service *svc)
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{
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if (atomic_read(&dest->activeconns) > atomic_read(&dest->weight)) {
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struct ip_vs_dest *d;
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list_for_each_entry(d, &svc->destinations, n_list) {
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if (atomic_read(&d->activeconns)*2
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< atomic_read(&d->weight)) {
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return 1;
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}
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}
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}
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return 0;
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}
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/*
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* Locality-Based (weighted) Least-Connection scheduling
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*/
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static struct ip_vs_dest *
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ip_vs_lblc_schedule(struct ip_vs_service *svc, const struct sk_buff *skb)
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{
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struct ip_vs_dest *dest;
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struct ip_vs_lblc_table *tbl;
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struct ip_vs_lblc_entry *en;
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struct iphdr *iph = ip_hdr(skb);
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IP_VS_DBG(6, "ip_vs_lblc_schedule(): Scheduling...\n");
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|
|
|
tbl = (struct ip_vs_lblc_table *)svc->sched_data;
|
|
en = ip_vs_lblc_get(tbl, iph->daddr);
|
|
if (en == NULL) {
|
|
dest = __ip_vs_wlc_schedule(svc, iph);
|
|
if (dest == NULL) {
|
|
IP_VS_DBG(1, "no destination available\n");
|
|
return NULL;
|
|
}
|
|
en = ip_vs_lblc_new(iph->daddr, dest);
|
|
if (en == NULL) {
|
|
return NULL;
|
|
}
|
|
ip_vs_lblc_hash(tbl, en);
|
|
} else {
|
|
dest = en->dest;
|
|
if (!(dest->flags & IP_VS_DEST_F_AVAILABLE)
|
|
|| atomic_read(&dest->weight) <= 0
|
|
|| is_overloaded(dest, svc)) {
|
|
dest = __ip_vs_wlc_schedule(svc, iph);
|
|
if (dest == NULL) {
|
|
IP_VS_DBG(1, "no destination available\n");
|
|
return NULL;
|
|
}
|
|
atomic_dec(&en->dest->refcnt);
|
|
atomic_inc(&dest->refcnt);
|
|
en->dest = dest;
|
|
}
|
|
}
|
|
en->lastuse = jiffies;
|
|
|
|
IP_VS_DBG(6, "LBLC: destination IP address %u.%u.%u.%u "
|
|
"--> server %u.%u.%u.%u:%d\n",
|
|
NIPQUAD(en->addr),
|
|
NIPQUAD(dest->addr),
|
|
ntohs(dest->port));
|
|
|
|
return dest;
|
|
}
|
|
|
|
|
|
/*
|
|
* IPVS LBLC Scheduler structure
|
|
*/
|
|
static struct ip_vs_scheduler ip_vs_lblc_scheduler =
|
|
{
|
|
.name = "lblc",
|
|
.refcnt = ATOMIC_INIT(0),
|
|
.module = THIS_MODULE,
|
|
.init_service = ip_vs_lblc_init_svc,
|
|
.done_service = ip_vs_lblc_done_svc,
|
|
.update_service = ip_vs_lblc_update_svc,
|
|
.schedule = ip_vs_lblc_schedule,
|
|
};
|
|
|
|
|
|
static int __init ip_vs_lblc_init(void)
|
|
{
|
|
int ret;
|
|
|
|
INIT_LIST_HEAD(&ip_vs_lblc_scheduler.n_list);
|
|
sysctl_header = register_sysctl_table(lblc_root_table);
|
|
ret = register_ip_vs_scheduler(&ip_vs_lblc_scheduler);
|
|
if (ret)
|
|
unregister_sysctl_table(sysctl_header);
|
|
return ret;
|
|
}
|
|
|
|
|
|
static void __exit ip_vs_lblc_cleanup(void)
|
|
{
|
|
unregister_sysctl_table(sysctl_header);
|
|
unregister_ip_vs_scheduler(&ip_vs_lblc_scheduler);
|
|
}
|
|
|
|
|
|
module_init(ip_vs_lblc_init);
|
|
module_exit(ip_vs_lblc_cleanup);
|
|
MODULE_LICENSE("GPL");
|