diff options
| -rw-r--r-- | net/ipv4/ipvs/ip_vs_lblc.c | 204 |
1 files changed, 96 insertions, 108 deletions
diff --git a/net/ipv4/ipvs/ip_vs_lblc.c b/net/ipv4/ipvs/ip_vs_lblc.c index b9b334c..d2a43aa 100644 --- a/net/ipv4/ipvs/ip_vs_lblc.c +++ b/net/ipv4/ipvs/ip_vs_lblc.c @@ -96,7 +96,6 @@ struct ip_vs_lblc_entry { * IPVS lblc hash table */ struct ip_vs_lblc_table { - rwlock_t lock; /* lock for this table */ struct list_head bucket[IP_VS_LBLC_TAB_SIZE]; /* hash bucket */ atomic_t entries; /* number of entries */ int max_size; /* maximum size of entries */ @@ -123,31 +122,6 @@ static ctl_table vs_vars_table[] = { static struct ctl_table_header * sysctl_header; -/* - * new/free a ip_vs_lblc_entry, which is a mapping of a destionation - * IP address to a server. - */ -static inline struct ip_vs_lblc_entry * -ip_vs_lblc_new(__be32 daddr, struct ip_vs_dest *dest) -{ - struct ip_vs_lblc_entry *en; - - en = kmalloc(sizeof(struct ip_vs_lblc_entry), GFP_ATOMIC); - if (en == NULL) { - IP_VS_ERR("ip_vs_lblc_new(): no memory\n"); - return NULL; - } - - INIT_LIST_HEAD(&en->list); - en->addr = daddr; - - atomic_inc(&dest->refcnt); - en->dest = dest; - - return en; -} - - static inline void ip_vs_lblc_free(struct ip_vs_lblc_entry *en) { list_del(&en->list); @@ -173,55 +147,66 @@ static inline unsigned ip_vs_lblc_hashkey(__be32 addr) * Hash an entry in the ip_vs_lblc_table. * returns bool success. */ -static int +static void ip_vs_lblc_hash(struct ip_vs_lblc_table *tbl, struct ip_vs_lblc_entry *en) { - unsigned hash; - - if (!list_empty(&en->list)) { - IP_VS_ERR("ip_vs_lblc_hash(): request for already hashed, " - "called from %p\n", __builtin_return_address(0)); - return 0; - } + unsigned hash = ip_vs_lblc_hashkey(en->addr); - /* - * Hash by destination IP address - */ - hash = ip_vs_lblc_hashkey(en->addr); - - write_lock(&tbl->lock); list_add(&en->list, &tbl->bucket[hash]); atomic_inc(&tbl->entries); - write_unlock(&tbl->lock); - - return 1; } /* - * Get ip_vs_lblc_entry associated with supplied parameters. + * Get ip_vs_lblc_entry associated with supplied parameters. Called under read + * lock */ static inline struct ip_vs_lblc_entry * ip_vs_lblc_get(struct ip_vs_lblc_table *tbl, __be32 addr) { - unsigned hash; + unsigned hash = ip_vs_lblc_hashkey(addr); struct ip_vs_lblc_entry *en; - hash = ip_vs_lblc_hashkey(addr); + list_for_each_entry(en, &tbl->bucket[hash], list) + if (en->addr == addr) + return en; - read_lock(&tbl->lock); + return NULL; +} - list_for_each_entry(en, &tbl->bucket[hash], list) { - if (en->addr == addr) { - /* HIT */ - read_unlock(&tbl->lock); - return en; + +/* + * Create or update an ip_vs_lblc_entry, which is a mapping of a destination IP + * address to a server. Called under write lock. + */ +static inline struct ip_vs_lblc_entry * +ip_vs_lblc_new(struct ip_vs_lblc_table *tbl, __be32 daddr, + struct ip_vs_dest *dest) +{ + struct ip_vs_lblc_entry *en; + + en = ip_vs_lblc_get(tbl, daddr); + if (!en) { + en = kmalloc(sizeof(*en), GFP_ATOMIC); + if (!en) { + IP_VS_ERR("ip_vs_lblc_new(): no memory\n"); + return NULL; } - } - read_unlock(&tbl->lock); + en->addr = daddr; + en->lastuse = jiffies; - return NULL; + atomic_inc(&dest->refcnt); + en->dest = dest; + + ip_vs_lblc_hash(tbl, en); + } else if (en->dest != dest) { + atomic_dec(&en->dest->refcnt); + atomic_inc(&dest->refcnt); + en->dest = dest; + } + + return en; } @@ -230,30 +215,29 @@ ip_vs_lblc_get(struct ip_vs_lblc_table *tbl, __be32 addr) */ static void ip_vs_lblc_flush(struct ip_vs_lblc_table *tbl) { - int i; struct ip_vs_lblc_entry *en, *nxt; + int i; for (i=0; i<IP_VS_LBLC_TAB_SIZE; i++) { - write_lock(&tbl->lock); list_for_each_entry_safe(en, nxt, &tbl->bucket[i], list) { ip_vs_lblc_free(en); atomic_dec(&tbl->entries); } - write_unlock(&tbl->lock); } } -static inline void ip_vs_lblc_full_check(struct ip_vs_lblc_table *tbl) +static inline void ip_vs_lblc_full_check(struct ip_vs_service *svc) { + struct ip_vs_lblc_table *tbl = svc->sched_data; + struct ip_vs_lblc_entry *en, *nxt; unsigned long now = jiffies; int i, j; - struct ip_vs_lblc_entry *en, *nxt; for (i=0, j=tbl->rover; i<IP_VS_LBLC_TAB_SIZE; i++) { j = (j + 1) & IP_VS_LBLC_TAB_MASK; - write_lock(&tbl->lock); + write_lock(&svc->sched_lock); list_for_each_entry_safe(en, nxt, &tbl->bucket[j], list) { if (time_before(now, en->lastuse + sysctl_ip_vs_lblc_expiration)) @@ -262,7 +246,7 @@ static inline void ip_vs_lblc_full_check(struct ip_vs_lblc_table *tbl) ip_vs_lblc_free(en); atomic_dec(&tbl->entries); } - write_unlock(&tbl->lock); + write_unlock(&svc->sched_lock); } tbl->rover = j; } @@ -281,17 +265,16 @@ static inline void ip_vs_lblc_full_check(struct ip_vs_lblc_table *tbl) */ static void ip_vs_lblc_check_expire(unsigned long data) { - struct ip_vs_lblc_table *tbl; + struct ip_vs_service *svc = (struct ip_vs_service *) data; + struct ip_vs_lblc_table *tbl = svc->sched_data; unsigned long now = jiffies; int goal; int i, j; struct ip_vs_lblc_entry *en, *nxt; - tbl = (struct ip_vs_lblc_table *)data; - if ((tbl->counter % COUNT_FOR_FULL_EXPIRATION) == 0) { /* do full expiration check */ - ip_vs_lblc_full_check(tbl); + ip_vs_lblc_full_check(svc); tbl->counter = 1; goto out; } @@ -308,7 +291,7 @@ static void ip_vs_lblc_check_expire(unsigned long data) for (i=0, j=tbl->rover; i<IP_VS_LBLC_TAB_SIZE; i++) { j = (j + 1) & IP_VS_LBLC_TAB_MASK; - write_lock(&tbl->lock); + write_lock(&svc->sched_lock); list_for_each_entry_safe(en, nxt, &tbl->bucket[j], list) { if (time_before(now, en->lastuse + ENTRY_TIMEOUT)) continue; @@ -317,7 +300,7 @@ static void ip_vs_lblc_check_expire(unsigned long data) atomic_dec(&tbl->entries); goal--; } - write_unlock(&tbl->lock); + write_unlock(&svc->sched_lock); if (goal <= 0) break; } @@ -336,15 +319,14 @@ static int ip_vs_lblc_init_svc(struct ip_vs_service *svc) /* * Allocate the ip_vs_lblc_table for this service */ - tbl = kmalloc(sizeof(struct ip_vs_lblc_table), GFP_ATOMIC); + tbl = kmalloc(sizeof(*tbl), GFP_ATOMIC); if (tbl == NULL) { IP_VS_ERR("ip_vs_lblc_init_svc(): no memory\n"); return -ENOMEM; } svc->sched_data = tbl; IP_VS_DBG(6, "LBLC hash table (memory=%Zdbytes) allocated for " - "current service\n", - sizeof(struct ip_vs_lblc_table)); + "current service\n", sizeof(*tbl)); /* * Initialize the hash buckets @@ -352,7 +334,6 @@ static int ip_vs_lblc_init_svc(struct ip_vs_service *svc) for (i=0; i<IP_VS_LBLC_TAB_SIZE; i++) { INIT_LIST_HEAD(&tbl->bucket[i]); } - rwlock_init(&tbl->lock); tbl->max_size = IP_VS_LBLC_TAB_SIZE*16; tbl->rover = 0; tbl->counter = 1; @@ -361,9 +342,8 @@ static int ip_vs_lblc_init_svc(struct ip_vs_service *svc) * Hook periodic timer for garbage collection */ setup_timer(&tbl->periodic_timer, ip_vs_lblc_check_expire, - (unsigned long)tbl); - tbl->periodic_timer.expires = jiffies+CHECK_EXPIRE_INTERVAL; - add_timer(&tbl->periodic_timer); + (unsigned long)svc); + mod_timer(&tbl->periodic_timer, jiffies + CHECK_EXPIRE_INTERVAL); return 0; } @@ -380,9 +360,9 @@ static int ip_vs_lblc_done_svc(struct ip_vs_service *svc) ip_vs_lblc_flush(tbl); /* release the table itself */ - kfree(svc->sched_data); + kfree(tbl); IP_VS_DBG(6, "LBLC hash table (memory=%Zdbytes) released\n", - sizeof(struct ip_vs_lblc_table)); + sizeof(*tbl)); return 0; } @@ -478,46 +458,54 @@ is_overloaded(struct ip_vs_dest *dest, struct ip_vs_service *svc) static struct ip_vs_dest * ip_vs_lblc_schedule(struct ip_vs_service *svc, const struct sk_buff *skb) { - struct ip_vs_dest *dest; - struct ip_vs_lblc_table *tbl; - struct ip_vs_lblc_entry *en; + struct ip_vs_lblc_table *tbl = svc->sched_data; struct iphdr *iph = ip_hdr(skb); + struct ip_vs_dest *dest = NULL; + struct ip_vs_lblc_entry *en; IP_VS_DBG(6, "ip_vs_lblc_schedule(): Scheduling...\n"); - tbl = (struct ip_vs_lblc_table *)svc->sched_data; + /* First look in our cache */ + read_lock(&svc->sched_lock); en = ip_vs_lblc_get(tbl, iph->daddr); - if (en == NULL) { - dest = __ip_vs_lblc_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_lblc_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; - } + if (en) { + /* We only hold a read lock, but this is atomic */ + en->lastuse = jiffies; + + /* + * If the destination is not available, i.e. it's in the trash, + * we must ignore it, as it may be removed from under our feet, + * if someone drops our reference count. Our caller only makes + * sure that destinations, that are not in the trash, are not + * moved to the trash, while we are scheduling. But anyone can + * free up entries from the trash at any time. + */ + + if (en->dest->flags & IP_VS_DEST_F_AVAILABLE) + dest = en->dest; + } + read_unlock(&svc->sched_lock); + + /* If the destination has a weight and is not overloaded, use it */ + if (dest && atomic_read(&dest->weight) > 0 && !is_overloaded(dest, svc)) + goto out; + + /* No cache entry or it is invalid, time to schedule */ + dest = __ip_vs_lblc_schedule(svc, iph); + if (!dest) { + IP_VS_DBG(1, "no destination available\n"); + return NULL; } - en->lastuse = jiffies; + /* If we fail to create a cache entry, we'll just use the valid dest */ + write_lock(&svc->sched_lock); + ip_vs_lblc_new(tbl, iph->daddr, dest); + write_unlock(&svc->sched_lock); + +out: IP_VS_DBG(6, "LBLC: destination IP address %u.%u.%u.%u " "--> server %u.%u.%u.%u:%d\n", - NIPQUAD(en->addr), + NIPQUAD(iph->daddr), NIPQUAD(dest->addr), ntohs(dest->port)); |