|
|
|
@ -54,15 +54,11 @@
|
|
|
|
|
* 1. Nodes may appear in the tree only with the pool lock held.
|
|
|
|
|
* 2. Nodes may disappear from the tree only with the pool lock held
|
|
|
|
|
* AND reference count being 0.
|
|
|
|
|
* 3. Nodes appears and disappears from unused node list only under
|
|
|
|
|
* "inet_peer_unused_lock".
|
|
|
|
|
* 4. Global variable peer_total is modified under the pool lock.
|
|
|
|
|
* 5. struct inet_peer fields modification:
|
|
|
|
|
* 3. Global variable peer_total is modified under the pool lock.
|
|
|
|
|
* 4. struct inet_peer fields modification:
|
|
|
|
|
* avl_left, avl_right, avl_parent, avl_height: pool lock
|
|
|
|
|
* unused: unused node list lock
|
|
|
|
|
* refcnt: atomically against modifications on other CPU;
|
|
|
|
|
* usually under some other lock to prevent node disappearing
|
|
|
|
|
* dtime: unused node list lock
|
|
|
|
|
* daddr: unchangeable
|
|
|
|
|
* ip_id_count: atomic value (no lock needed)
|
|
|
|
|
*/
|
|
|
|
@ -104,19 +100,6 @@ int inet_peer_threshold __read_mostly = 65536 + 128; /* start to throw entries m
|
|
|
|
|
* aggressively at this stage */
|
|
|
|
|
int inet_peer_minttl __read_mostly = 120 * HZ; /* TTL under high load: 120 sec */
|
|
|
|
|
int inet_peer_maxttl __read_mostly = 10 * 60 * HZ; /* usual time to live: 10 min */
|
|
|
|
|
int inet_peer_gc_mintime __read_mostly = 10 * HZ;
|
|
|
|
|
int inet_peer_gc_maxtime __read_mostly = 120 * HZ;
|
|
|
|
|
|
|
|
|
|
static struct {
|
|
|
|
|
struct list_head list;
|
|
|
|
|
spinlock_t lock;
|
|
|
|
|
} unused_peers = {
|
|
|
|
|
.list = LIST_HEAD_INIT(unused_peers.list),
|
|
|
|
|
.lock = __SPIN_LOCK_UNLOCKED(unused_peers.lock),
|
|
|
|
|
};
|
|
|
|
|
|
|
|
|
|
static void peer_check_expire(unsigned long dummy);
|
|
|
|
|
static DEFINE_TIMER(peer_periodic_timer, peer_check_expire, 0, 0);
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
/* Called from ip_output.c:ip_init */
|
|
|
|
@ -142,21 +125,6 @@ void __init inet_initpeers(void)
|
|
|
|
|
0, SLAB_HWCACHE_ALIGN | SLAB_PANIC,
|
|
|
|
|
NULL);
|
|
|
|
|
|
|
|
|
|
/* All the timers, started at system startup tend
|
|
|
|
|
to synchronize. Perturb it a bit.
|
|
|
|
|
*/
|
|
|
|
|
peer_periodic_timer.expires = jiffies
|
|
|
|
|
+ net_random() % inet_peer_gc_maxtime
|
|
|
|
|
+ inet_peer_gc_maxtime;
|
|
|
|
|
add_timer(&peer_periodic_timer);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/* Called with or without local BH being disabled. */
|
|
|
|
|
static void unlink_from_unused(struct inet_peer *p)
|
|
|
|
|
{
|
|
|
|
|
spin_lock_bh(&unused_peers.lock);
|
|
|
|
|
list_del_init(&p->unused);
|
|
|
|
|
spin_unlock_bh(&unused_peers.lock);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static int addr_compare(const struct inetpeer_addr *a,
|
|
|
|
@ -203,20 +171,6 @@ static int addr_compare(const struct inetpeer_addr *a,
|
|
|
|
|
u; \
|
|
|
|
|
})
|
|
|
|
|
|
|
|
|
|
static bool atomic_add_unless_return(atomic_t *ptr, int a, int u, int *newv)
|
|
|
|
|
{
|
|
|
|
|
int cur, old = atomic_read(ptr);
|
|
|
|
|
|
|
|
|
|
while (old != u) {
|
|
|
|
|
*newv = old + a;
|
|
|
|
|
cur = atomic_cmpxchg(ptr, old, *newv);
|
|
|
|
|
if (cur == old)
|
|
|
|
|
return true;
|
|
|
|
|
old = cur;
|
|
|
|
|
}
|
|
|
|
|
return false;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* Called with rcu_read_lock()
|
|
|
|
|
* Because we hold no lock against a writer, its quite possible we fall
|
|
|
|
@ -225,8 +179,7 @@ static bool atomic_add_unless_return(atomic_t *ptr, int a, int u, int *newv)
|
|
|
|
|
* We exit from this function if number of links exceeds PEER_MAXDEPTH
|
|
|
|
|
*/
|
|
|
|
|
static struct inet_peer *lookup_rcu(const struct inetpeer_addr *daddr,
|
|
|
|
|
struct inet_peer_base *base,
|
|
|
|
|
int *newrefcnt)
|
|
|
|
|
struct inet_peer_base *base)
|
|
|
|
|
{
|
|
|
|
|
struct inet_peer *u = rcu_dereference(base->root);
|
|
|
|
|
int count = 0;
|
|
|
|
@ -235,11 +188,9 @@ static struct inet_peer *lookup_rcu(const struct inetpeer_addr *daddr,
|
|
|
|
|
int cmp = addr_compare(daddr, &u->daddr);
|
|
|
|
|
if (cmp == 0) {
|
|
|
|
|
/* Before taking a reference, check if this entry was
|
|
|
|
|
* deleted, unlink_from_pool() sets refcnt=-1 to make
|
|
|
|
|
* distinction between an unused entry (refcnt=0) and
|
|
|
|
|
* a freed one.
|
|
|
|
|
* deleted (refcnt=-1)
|
|
|
|
|
*/
|
|
|
|
|
if (!atomic_add_unless_return(&u->refcnt, 1, -1, newrefcnt))
|
|
|
|
|
if (!atomic_add_unless(&u->refcnt, 1, -1))
|
|
|
|
|
u = NULL;
|
|
|
|
|
return u;
|
|
|
|
|
}
|
|
|
|
@ -366,137 +317,96 @@ static void inetpeer_free_rcu(struct rcu_head *head)
|
|
|
|
|
kmem_cache_free(peer_cachep, container_of(head, struct inet_peer, rcu));
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/* May be called with local BH enabled. */
|
|
|
|
|
static void unlink_from_pool(struct inet_peer *p, struct inet_peer_base *base,
|
|
|
|
|
struct inet_peer __rcu **stack[PEER_MAXDEPTH])
|
|
|
|
|
{
|
|
|
|
|
int do_free;
|
|
|
|
|
struct inet_peer __rcu ***stackptr, ***delp;
|
|
|
|
|
|
|
|
|
|
do_free = 0;
|
|
|
|
|
|
|
|
|
|
write_seqlock_bh(&base->lock);
|
|
|
|
|
/* Check the reference counter. It was artificially incremented by 1
|
|
|
|
|
* in cleanup() function to prevent sudden disappearing. If we can
|
|
|
|
|
* atomically (because of lockless readers) take this last reference,
|
|
|
|
|
* it's safe to remove the node and free it later.
|
|
|
|
|
* We use refcnt=-1 to alert lockless readers this entry is deleted.
|
|
|
|
|
*/
|
|
|
|
|
if (atomic_cmpxchg(&p->refcnt, 1, -1) == 1) {
|
|
|
|
|
struct inet_peer __rcu ***stackptr, ***delp;
|
|
|
|
|
if (lookup(&p->daddr, stack, base) != p)
|
|
|
|
|
BUG();
|
|
|
|
|
delp = stackptr - 1; /* *delp[0] == p */
|
|
|
|
|
if (p->avl_left == peer_avl_empty_rcu) {
|
|
|
|
|
*delp[0] = p->avl_right;
|
|
|
|
|
--stackptr;
|
|
|
|
|
} else {
|
|
|
|
|
/* look for a node to insert instead of p */
|
|
|
|
|
struct inet_peer *t;
|
|
|
|
|
t = lookup_rightempty(p, base);
|
|
|
|
|
BUG_ON(rcu_deref_locked(*stackptr[-1], base) != t);
|
|
|
|
|
**--stackptr = t->avl_left;
|
|
|
|
|
/* t is removed, t->daddr > x->daddr for any
|
|
|
|
|
* x in p->avl_left subtree.
|
|
|
|
|
* Put t in the old place of p. */
|
|
|
|
|
RCU_INIT_POINTER(*delp[0], t);
|
|
|
|
|
t->avl_left = p->avl_left;
|
|
|
|
|
t->avl_right = p->avl_right;
|
|
|
|
|
t->avl_height = p->avl_height;
|
|
|
|
|
BUG_ON(delp[1] != &p->avl_left);
|
|
|
|
|
delp[1] = &t->avl_left; /* was &p->avl_left */
|
|
|
|
|
}
|
|
|
|
|
peer_avl_rebalance(stack, stackptr, base);
|
|
|
|
|
base->total--;
|
|
|
|
|
do_free = 1;
|
|
|
|
|
if (lookup(&p->daddr, stack, base) != p)
|
|
|
|
|
BUG();
|
|
|
|
|
delp = stackptr - 1; /* *delp[0] == p */
|
|
|
|
|
if (p->avl_left == peer_avl_empty_rcu) {
|
|
|
|
|
*delp[0] = p->avl_right;
|
|
|
|
|
--stackptr;
|
|
|
|
|
} else {
|
|
|
|
|
/* look for a node to insert instead of p */
|
|
|
|
|
struct inet_peer *t;
|
|
|
|
|
t = lookup_rightempty(p, base);
|
|
|
|
|
BUG_ON(rcu_deref_locked(*stackptr[-1], base) != t);
|
|
|
|
|
**--stackptr = t->avl_left;
|
|
|
|
|
/* t is removed, t->daddr > x->daddr for any
|
|
|
|
|
* x in p->avl_left subtree.
|
|
|
|
|
* Put t in the old place of p. */
|
|
|
|
|
RCU_INIT_POINTER(*delp[0], t);
|
|
|
|
|
t->avl_left = p->avl_left;
|
|
|
|
|
t->avl_right = p->avl_right;
|
|
|
|
|
t->avl_height = p->avl_height;
|
|
|
|
|
BUG_ON(delp[1] != &p->avl_left);
|
|
|
|
|
delp[1] = &t->avl_left; /* was &p->avl_left */
|
|
|
|
|
}
|
|
|
|
|
write_sequnlock_bh(&base->lock);
|
|
|
|
|
|
|
|
|
|
if (do_free)
|
|
|
|
|
call_rcu(&p->rcu, inetpeer_free_rcu);
|
|
|
|
|
else
|
|
|
|
|
/* The node is used again. Decrease the reference counter
|
|
|
|
|
* back. The loop "cleanup -> unlink_from_unused
|
|
|
|
|
* -> unlink_from_pool -> putpeer -> link_to_unused
|
|
|
|
|
* -> cleanup (for the same node)"
|
|
|
|
|
* doesn't really exist because the entry will have a
|
|
|
|
|
* recent deletion time and will not be cleaned again soon.
|
|
|
|
|
*/
|
|
|
|
|
inet_putpeer(p);
|
|
|
|
|
peer_avl_rebalance(stack, stackptr, base);
|
|
|
|
|
base->total--;
|
|
|
|
|
call_rcu(&p->rcu, inetpeer_free_rcu);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static struct inet_peer_base *family_to_base(int family)
|
|
|
|
|
{
|
|
|
|
|
return (family == AF_INET ? &v4_peers : &v6_peers);
|
|
|
|
|
return family == AF_INET ? &v4_peers : &v6_peers;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static struct inet_peer_base *peer_to_base(struct inet_peer *p)
|
|
|
|
|
/* perform garbage collect on all items stacked during a lookup */
|
|
|
|
|
static int inet_peer_gc(struct inet_peer_base *base,
|
|
|
|
|
struct inet_peer __rcu **stack[PEER_MAXDEPTH],
|
|
|
|
|
struct inet_peer __rcu ***stackptr)
|
|
|
|
|
{
|
|
|
|
|
return family_to_base(p->daddr.family);
|
|
|
|
|
}
|
|
|
|
|
struct inet_peer *p, *gchead = NULL;
|
|
|
|
|
__u32 delta, ttl;
|
|
|
|
|
int cnt = 0;
|
|
|
|
|
|
|
|
|
|
/* May be called with local BH enabled. */
|
|
|
|
|
static int cleanup_once(unsigned long ttl, struct inet_peer __rcu **stack[PEER_MAXDEPTH])
|
|
|
|
|
{
|
|
|
|
|
struct inet_peer *p = NULL;
|
|
|
|
|
|
|
|
|
|
/* Remove the first entry from the list of unused nodes. */
|
|
|
|
|
spin_lock_bh(&unused_peers.lock);
|
|
|
|
|
if (!list_empty(&unused_peers.list)) {
|
|
|
|
|
__u32 delta;
|
|
|
|
|
|
|
|
|
|
p = list_first_entry(&unused_peers.list, struct inet_peer, unused);
|
|
|
|
|
if (base->total >= inet_peer_threshold)
|
|
|
|
|
ttl = 0; /* be aggressive */
|
|
|
|
|
else
|
|
|
|
|
ttl = inet_peer_maxttl
|
|
|
|
|
- (inet_peer_maxttl - inet_peer_minttl) / HZ *
|
|
|
|
|
base->total / inet_peer_threshold * HZ;
|
|
|
|
|
stackptr--; /* last stack slot is peer_avl_empty */
|
|
|
|
|
while (stackptr > stack) {
|
|
|
|
|
stackptr--;
|
|
|
|
|
p = rcu_deref_locked(**stackptr, base);
|
|
|
|
|
delta = (__u32)jiffies - p->dtime;
|
|
|
|
|
|
|
|
|
|
if (delta < ttl) {
|
|
|
|
|
/* Do not prune fresh entries. */
|
|
|
|
|
spin_unlock_bh(&unused_peers.lock);
|
|
|
|
|
return -1;
|
|
|
|
|
if (atomic_read(&p->refcnt) == 0 && delta >= ttl &&
|
|
|
|
|
atomic_cmpxchg(&p->refcnt, 0, -1) == 0) {
|
|
|
|
|
p->gc_next = gchead;
|
|
|
|
|
gchead = p;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
list_del_init(&p->unused);
|
|
|
|
|
|
|
|
|
|
/* Grab an extra reference to prevent node disappearing
|
|
|
|
|
* before unlink_from_pool() call. */
|
|
|
|
|
atomic_inc(&p->refcnt);
|
|
|
|
|
}
|
|
|
|
|
spin_unlock_bh(&unused_peers.lock);
|
|
|
|
|
|
|
|
|
|
if (p == NULL)
|
|
|
|
|
/* It means that the total number of USED entries has
|
|
|
|
|
* grown over inet_peer_threshold. It shouldn't really
|
|
|
|
|
* happen because of entry limits in route cache. */
|
|
|
|
|
return -1;
|
|
|
|
|
|
|
|
|
|
unlink_from_pool(p, peer_to_base(p), stack);
|
|
|
|
|
return 0;
|
|
|
|
|
while ((p = gchead) != NULL) {
|
|
|
|
|
gchead = p->gc_next;
|
|
|
|
|
cnt++;
|
|
|
|
|
unlink_from_pool(p, base, stack);
|
|
|
|
|
}
|
|
|
|
|
return cnt;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/* Called with or without local BH being disabled. */
|
|
|
|
|
struct inet_peer *inet_getpeer(struct inetpeer_addr *daddr, int create)
|
|
|
|
|
{
|
|
|
|
|
struct inet_peer __rcu **stack[PEER_MAXDEPTH], ***stackptr;
|
|
|
|
|
struct inet_peer_base *base = family_to_base(daddr->family);
|
|
|
|
|
struct inet_peer *p;
|
|
|
|
|
unsigned int sequence;
|
|
|
|
|
int invalidated, newrefcnt = 0;
|
|
|
|
|
int invalidated, gccnt = 0;
|
|
|
|
|
|
|
|
|
|
/* Look up for the address quickly, lockless.
|
|
|
|
|
/* Attempt a lockless lookup first.
|
|
|
|
|
* Because of a concurrent writer, we might not find an existing entry.
|
|
|
|
|
*/
|
|
|
|
|
rcu_read_lock();
|
|
|
|
|
sequence = read_seqbegin(&base->lock);
|
|
|
|
|
p = lookup_rcu(daddr, base, &newrefcnt);
|
|
|
|
|
p = lookup_rcu(daddr, base);
|
|
|
|
|
invalidated = read_seqretry(&base->lock, sequence);
|
|
|
|
|
rcu_read_unlock();
|
|
|
|
|
|
|
|
|
|
if (p) {
|
|
|
|
|
found: /* The existing node has been found.
|
|
|
|
|
* Remove the entry from unused list if it was there.
|
|
|
|
|
*/
|
|
|
|
|
if (newrefcnt == 1)
|
|
|
|
|
unlink_from_unused(p);
|
|
|
|
|
if (p)
|
|
|
|
|
return p;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/* If no writer did a change during our lookup, we can return early. */
|
|
|
|
|
if (!create && !invalidated)
|
|
|
|
@ -506,11 +416,17 @@ found: /* The existing node has been found.
|
|
|
|
|
* At least, nodes should be hot in our cache.
|
|
|
|
|
*/
|
|
|
|
|
write_seqlock_bh(&base->lock);
|
|
|
|
|
relookup:
|
|
|
|
|
p = lookup(daddr, stack, base);
|
|
|
|
|
if (p != peer_avl_empty) {
|
|
|
|
|
newrefcnt = atomic_inc_return(&p->refcnt);
|
|
|
|
|
atomic_inc(&p->refcnt);
|
|
|
|
|
write_sequnlock_bh(&base->lock);
|
|
|
|
|
goto found;
|
|
|
|
|
return p;
|
|
|
|
|
}
|
|
|
|
|
if (!gccnt) {
|
|
|
|
|
gccnt = inet_peer_gc(base, stack, stackptr);
|
|
|
|
|
if (gccnt && create)
|
|
|
|
|
goto relookup;
|
|
|
|
|
}
|
|
|
|
|
p = create ? kmem_cache_alloc(peer_cachep, GFP_ATOMIC) : NULL;
|
|
|
|
|
if (p) {
|
|
|
|
@ -525,7 +441,6 @@ found: /* The existing node has been found.
|
|
|
|
|
p->pmtu_expires = 0;
|
|
|
|
|
p->pmtu_orig = 0;
|
|
|
|
|
memset(&p->redirect_learned, 0, sizeof(p->redirect_learned));
|
|
|
|
|
INIT_LIST_HEAD(&p->unused);
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
/* Link the node. */
|
|
|
|
@ -534,63 +449,14 @@ found: /* The existing node has been found.
|
|
|
|
|
}
|
|
|
|
|
write_sequnlock_bh(&base->lock);
|
|
|
|
|
|
|
|
|
|
if (base->total >= inet_peer_threshold)
|
|
|
|
|
/* Remove one less-recently-used entry. */
|
|
|
|
|
cleanup_once(0, stack);
|
|
|
|
|
|
|
|
|
|
return p;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static int compute_total(void)
|
|
|
|
|
{
|
|
|
|
|
return v4_peers.total + v6_peers.total;
|
|
|
|
|
}
|
|
|
|
|
EXPORT_SYMBOL_GPL(inet_getpeer);
|
|
|
|
|
|
|
|
|
|
/* Called with local BH disabled. */
|
|
|
|
|
static void peer_check_expire(unsigned long dummy)
|
|
|
|
|
{
|
|
|
|
|
unsigned long now = jiffies;
|
|
|
|
|
int ttl, total;
|
|
|
|
|
struct inet_peer __rcu **stack[PEER_MAXDEPTH];
|
|
|
|
|
|
|
|
|
|
total = compute_total();
|
|
|
|
|
if (total >= inet_peer_threshold)
|
|
|
|
|
ttl = inet_peer_minttl;
|
|
|
|
|
else
|
|
|
|
|
ttl = inet_peer_maxttl
|
|
|
|
|
- (inet_peer_maxttl - inet_peer_minttl) / HZ *
|
|
|
|
|
total / inet_peer_threshold * HZ;
|
|
|
|
|
while (!cleanup_once(ttl, stack)) {
|
|
|
|
|
if (jiffies != now)
|
|
|
|
|
break;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/* Trigger the timer after inet_peer_gc_mintime .. inet_peer_gc_maxtime
|
|
|
|
|
* interval depending on the total number of entries (more entries,
|
|
|
|
|
* less interval). */
|
|
|
|
|
total = compute_total();
|
|
|
|
|
if (total >= inet_peer_threshold)
|
|
|
|
|
peer_periodic_timer.expires = jiffies + inet_peer_gc_mintime;
|
|
|
|
|
else
|
|
|
|
|
peer_periodic_timer.expires = jiffies
|
|
|
|
|
+ inet_peer_gc_maxtime
|
|
|
|
|
- (inet_peer_gc_maxtime - inet_peer_gc_mintime) / HZ *
|
|
|
|
|
total / inet_peer_threshold * HZ;
|
|
|
|
|
add_timer(&peer_periodic_timer);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
void inet_putpeer(struct inet_peer *p)
|
|
|
|
|
{
|
|
|
|
|
local_bh_disable();
|
|
|
|
|
|
|
|
|
|
if (atomic_dec_and_lock(&p->refcnt, &unused_peers.lock)) {
|
|
|
|
|
list_add_tail(&p->unused, &unused_peers.list);
|
|
|
|
|
p->dtime = (__u32)jiffies;
|
|
|
|
|
spin_unlock(&unused_peers.lock);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
local_bh_enable();
|
|
|
|
|
p->dtime = (__u32)jiffies;
|
|
|
|
|
atomic_dec(&p->refcnt);
|
|
|
|
|
}
|
|
|
|
|
EXPORT_SYMBOL_GPL(inet_putpeer);
|
|
|
|
|
|
|
|
|
|