* 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 */
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);
* 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;
}
*/
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))
ip_vs_lblc_free(en);
atomic_dec(&tbl->entries);
}
- write_unlock(&tbl->lock);
+ write_unlock(&svc->sched_lock);
}
tbl->rover = j;
}
*/
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;
}
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;
atomic_dec(&tbl->entries);
goal--;
}
- write_unlock(&tbl->lock);
+ write_unlock(&svc->sched_lock);
if (goal <= 0)
break;
}
/*
* 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
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;
* 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;
}
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;
}
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));
projects / linux-2.6-omap-h63xx.git / commitdiff