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Message-Id: <20101130.132157.246510731.davem@davemloft.net>
Date: Tue, 30 Nov 2010 13:21:57 -0800 (PST)
From: David Miller <davem@...emloft.net>
To: netdev@...r.kernel.org
Subject: [PATCH 1/8] inetpeer: Abstract out the tree root accesses.
Instead of directly accessing "peer", change to code to
operate using a "struct inet_peer_base *" pointer.
This will facilitate the addition of a seperate tree for
ipv6 peer entries.
Signed-off-by: David S. Miller <davem@...emloft.net>
---
net/ipv4/inetpeer.c | 119 +++++++++++++++++++++++++++++---------------------
1 files changed, 69 insertions(+), 50 deletions(-)
diff --git a/net/ipv4/inetpeer.c b/net/ipv4/inetpeer.c
index 9e94d7c..f944008 100644
--- a/net/ipv4/inetpeer.c
+++ b/net/ipv4/inetpeer.c
@@ -79,13 +79,13 @@ static const struct inet_peer peer_fake_node = {
.avl_height = 0
};
-static struct {
+static struct inet_peer_base {
struct inet_peer __rcu *root;
spinlock_t lock;
int total;
-} peers = {
+} v4_peers = {
.root = peer_avl_empty_rcu,
- .lock = __SPIN_LOCK_UNLOCKED(peers.lock),
+ .lock = __SPIN_LOCK_UNLOCKED(v4_peers.lock),
.total = 0,
};
#define PEER_MAXDEPTH 40 /* sufficient for about 2^27 nodes */
@@ -155,15 +155,15 @@ static void unlink_from_unused(struct inet_peer *p)
/*
* Called with local BH disabled and the pool lock held.
*/
-#define lookup(_daddr, _stack) \
+#define lookup(_daddr, _stack, _base) \
({ \
struct inet_peer *u; \
struct inet_peer __rcu **v; \
\
stackptr = _stack; \
- *stackptr++ = &peers.root; \
- for (u = rcu_dereference_protected(peers.root, \
- lockdep_is_held(&peers.lock)); \
+ *stackptr++ = &_base->root; \
+ for (u = rcu_dereference_protected(_base->root, \
+ lockdep_is_held(&_base->lock)); \
u != peer_avl_empty; ) { \
if (_daddr == u->v4daddr) \
break; \
@@ -173,7 +173,7 @@ static void unlink_from_unused(struct inet_peer *p)
v = &u->avl_right; \
*stackptr++ = v; \
u = rcu_dereference_protected(*v, \
- lockdep_is_held(&peers.lock)); \
+ lockdep_is_held(&_base->lock)); \
} \
u; \
})
@@ -185,9 +185,9 @@ static void unlink_from_unused(struct inet_peer *p)
* But every pointer we follow is guaranteed to be valid thanks to RCU.
* We exit from this function if number of links exceeds PEER_MAXDEPTH
*/
-static struct inet_peer *lookup_rcu_bh(__be32 daddr)
+static struct inet_peer *lookup_rcu_bh(__be32 daddr, struct inet_peer_base *base)
{
- struct inet_peer *u = rcu_dereference_bh(peers.root);
+ struct inet_peer *u = rcu_dereference_bh(base->root);
int count = 0;
while (u != peer_avl_empty) {
@@ -212,19 +212,19 @@ static struct inet_peer *lookup_rcu_bh(__be32 daddr)
}
/* Called with local BH disabled and the pool lock held. */
-#define lookup_rightempty(start) \
+#define lookup_rightempty(start, base) \
({ \
struct inet_peer *u; \
struct inet_peer __rcu **v; \
*stackptr++ = &start->avl_left; \
v = &start->avl_left; \
for (u = rcu_dereference_protected(*v, \
- lockdep_is_held(&peers.lock)); \
+ lockdep_is_held(&base->lock)); \
u->avl_right != peer_avl_empty_rcu; ) { \
v = &u->avl_right; \
*stackptr++ = v; \
u = rcu_dereference_protected(*v, \
- lockdep_is_held(&peers.lock)); \
+ lockdep_is_held(&base->lock)); \
} \
u; \
})
@@ -234,7 +234,8 @@ static struct inet_peer *lookup_rcu_bh(__be32 daddr)
* Look into mm/map_avl.c for more detail description of the ideas.
*/
static void peer_avl_rebalance(struct inet_peer __rcu **stack[],
- struct inet_peer __rcu ***stackend)
+ struct inet_peer __rcu ***stackend,
+ struct inet_peer_base *base)
{
struct inet_peer __rcu **nodep;
struct inet_peer *node, *l, *r;
@@ -243,20 +244,20 @@ static void peer_avl_rebalance(struct inet_peer __rcu **stack[],
while (stackend > stack) {
nodep = *--stackend;
node = rcu_dereference_protected(*nodep,
- lockdep_is_held(&peers.lock));
+ lockdep_is_held(&base->lock));
l = rcu_dereference_protected(node->avl_left,
- lockdep_is_held(&peers.lock));
+ lockdep_is_held(&base->lock));
r = rcu_dereference_protected(node->avl_right,
- lockdep_is_held(&peers.lock));
+ lockdep_is_held(&base->lock));
lh = node_height(l);
rh = node_height(r);
if (lh > rh + 1) { /* l: RH+2 */
struct inet_peer *ll, *lr, *lrl, *lrr;
int lrh;
ll = rcu_dereference_protected(l->avl_left,
- lockdep_is_held(&peers.lock));
+ lockdep_is_held(&base->lock));
lr = rcu_dereference_protected(l->avl_right,
- lockdep_is_held(&peers.lock));
+ lockdep_is_held(&base->lock));
lrh = node_height(lr);
if (lrh <= node_height(ll)) { /* ll: RH+1 */
RCU_INIT_POINTER(node->avl_left, lr); /* lr: RH or RH+1 */
@@ -268,9 +269,9 @@ static void peer_avl_rebalance(struct inet_peer __rcu **stack[],
RCU_INIT_POINTER(*nodep, l);
} else { /* ll: RH, lr: RH+1 */
lrl = rcu_dereference_protected(lr->avl_left,
- lockdep_is_held(&peers.lock)); /* lrl: RH or RH-1 */
+ lockdep_is_held(&base->lock)); /* lrl: RH or RH-1 */
lrr = rcu_dereference_protected(lr->avl_right,
- lockdep_is_held(&peers.lock)); /* lrr: RH or RH-1 */
+ lockdep_is_held(&base->lock)); /* lrr: RH or RH-1 */
RCU_INIT_POINTER(node->avl_left, lrr); /* lrr: RH or RH-1 */
RCU_INIT_POINTER(node->avl_right, r); /* r: RH */
node->avl_height = rh + 1; /* node: RH+1 */
@@ -286,9 +287,9 @@ static void peer_avl_rebalance(struct inet_peer __rcu **stack[],
struct inet_peer *rr, *rl, *rlr, *rll;
int rlh;
rr = rcu_dereference_protected(r->avl_right,
- lockdep_is_held(&peers.lock));
+ lockdep_is_held(&base->lock));
rl = rcu_dereference_protected(r->avl_left,
- lockdep_is_held(&peers.lock));
+ lockdep_is_held(&base->lock));
rlh = node_height(rl);
if (rlh <= node_height(rr)) { /* rr: LH+1 */
RCU_INIT_POINTER(node->avl_right, rl); /* rl: LH or LH+1 */
@@ -300,9 +301,9 @@ static void peer_avl_rebalance(struct inet_peer __rcu **stack[],
RCU_INIT_POINTER(*nodep, r);
} else { /* rr: RH, rl: RH+1 */
rlr = rcu_dereference_protected(rl->avl_right,
- lockdep_is_held(&peers.lock)); /* rlr: LH or LH-1 */
+ lockdep_is_held(&base->lock)); /* rlr: LH or LH-1 */
rll = rcu_dereference_protected(rl->avl_left,
- lockdep_is_held(&peers.lock)); /* rll: LH or LH-1 */
+ lockdep_is_held(&base->lock)); /* rll: LH or LH-1 */
RCU_INIT_POINTER(node->avl_right, rll); /* rll: LH or LH-1 */
RCU_INIT_POINTER(node->avl_left, l); /* l: LH */
node->avl_height = lh + 1; /* node: LH+1 */
@@ -321,14 +322,14 @@ static void peer_avl_rebalance(struct inet_peer __rcu **stack[],
}
/* Called with local BH disabled and the pool lock held. */
-#define link_to_pool(n) \
+#define link_to_pool(n, base) \
do { \
n->avl_height = 1; \
n->avl_left = peer_avl_empty_rcu; \
n->avl_right = peer_avl_empty_rcu; \
/* lockless readers can catch us now */ \
rcu_assign_pointer(**--stackptr, n); \
- peer_avl_rebalance(stack, stackptr); \
+ peer_avl_rebalance(stack, stackptr, base); \
} while (0)
static void inetpeer_free_rcu(struct rcu_head *head)
@@ -337,13 +338,13 @@ static void inetpeer_free_rcu(struct rcu_head *head)
}
/* May be called with local BH enabled. */
-static void unlink_from_pool(struct inet_peer *p)
+static void unlink_from_pool(struct inet_peer *p, struct inet_peer_base *base)
{
int do_free;
do_free = 0;
- spin_lock_bh(&peers.lock);
+ spin_lock_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,
@@ -353,7 +354,7 @@ static void unlink_from_pool(struct inet_peer *p)
if (atomic_cmpxchg(&p->refcnt, 1, -1) == 1) {
struct inet_peer __rcu **stack[PEER_MAXDEPTH];
struct inet_peer __rcu ***stackptr, ***delp;
- if (lookup(p->v4daddr, stack) != p)
+ if (lookup(p->v4daddr, stack, base) != p)
BUG();
delp = stackptr - 1; /* *delp[0] == p */
if (p->avl_left == peer_avl_empty_rcu) {
@@ -362,9 +363,9 @@ static void unlink_from_pool(struct inet_peer *p)
} else {
/* look for a node to insert instead of p */
struct inet_peer *t;
- t = lookup_rightempty(p);
+ t = lookup_rightempty(p, base);
BUG_ON(rcu_dereference_protected(*stackptr[-1],
- lockdep_is_held(&peers.lock)) != t);
+ lockdep_is_held(&base->lock)) != t);
**--stackptr = t->avl_left;
/* t is removed, t->v4daddr > x->v4daddr for any
* x in p->avl_left subtree.
@@ -376,11 +377,11 @@ static void unlink_from_pool(struct inet_peer *p)
BUG_ON(delp[1] != &p->avl_left);
delp[1] = &t->avl_left; /* was &p->avl_left */
}
- peer_avl_rebalance(stack, stackptr);
- peers.total--;
+ peer_avl_rebalance(stack, stackptr, base);
+ base->total--;
do_free = 1;
}
- spin_unlock_bh(&peers.lock);
+ spin_unlock_bh(&base->lock);
if (do_free)
call_rcu_bh(&p->rcu, inetpeer_free_rcu);
@@ -395,6 +396,11 @@ static void unlink_from_pool(struct inet_peer *p)
inet_putpeer(p);
}
+static struct inet_peer_base *peer_to_base(struct inet_peer *p)
+{
+ return &v4_peers;
+}
+
/* May be called with local BH enabled. */
static int cleanup_once(unsigned long ttl)
{
@@ -428,21 +434,27 @@ static int cleanup_once(unsigned long ttl)
* happen because of entry limits in route cache. */
return -1;
- unlink_from_pool(p);
+ unlink_from_pool(p, peer_to_base(p));
return 0;
}
+static struct inet_peer_base *family_to_base(int family)
+{
+ return &v4_peers;
+}
+
/* Called with or without local BH being disabled. */
struct inet_peer *inet_getpeer(__be32 daddr, int create)
{
- struct inet_peer *p;
struct inet_peer __rcu **stack[PEER_MAXDEPTH], ***stackptr;
+ struct inet_peer_base *base = family_to_base(AF_INET);
+ struct inet_peer *p;
/* Look up for the address quickly, lockless.
* Because of a concurrent writer, we might not find an existing entry.
*/
rcu_read_lock_bh();
- p = lookup_rcu_bh(daddr);
+ p = lookup_rcu_bh(daddr, base);
rcu_read_unlock_bh();
if (p) {
@@ -456,11 +468,11 @@ struct inet_peer *inet_getpeer(__be32 daddr, int create)
/* retry an exact lookup, taking the lock before.
* At least, nodes should be hot in our cache.
*/
- spin_lock_bh(&peers.lock);
- p = lookup(daddr, stack);
+ spin_lock_bh(&base->lock);
+ p = lookup(daddr, stack, base);
if (p != peer_avl_empty) {
atomic_inc(&p->refcnt);
- spin_unlock_bh(&peers.lock);
+ spin_unlock_bh(&base->lock);
/* Remove the entry from unused list if it was there. */
unlink_from_unused(p);
return p;
@@ -476,30 +488,36 @@ struct inet_peer *inet_getpeer(__be32 daddr, int create)
/* Link the node. */
- link_to_pool(p);
- peers.total++;
+ link_to_pool(p, base);
+ base->total++;
}
- spin_unlock_bh(&peers.lock);
+ spin_unlock_bh(&base->lock);
- if (peers.total >= inet_peer_threshold)
+ if (base->total >= inet_peer_threshold)
/* Remove one less-recently-used entry. */
cleanup_once(0);
return p;
}
+static int compute_total(void)
+{
+ return v4_peers.total;
+}
+
/* Called with local BH disabled. */
static void peer_check_expire(unsigned long dummy)
{
unsigned long now = jiffies;
- int ttl;
+ int ttl, total;
- if (peers.total >= inet_peer_threshold)
+ total = compute_total();
+ if (total >= inet_peer_threshold)
ttl = inet_peer_minttl;
else
ttl = inet_peer_maxttl
- (inet_peer_maxttl - inet_peer_minttl) / HZ *
- peers.total / inet_peer_threshold * HZ;
+ total / inet_peer_threshold * HZ;
while (!cleanup_once(ttl)) {
if (jiffies != now)
break;
@@ -508,13 +526,14 @@ static void peer_check_expire(unsigned long dummy)
/* Trigger the timer after inet_peer_gc_mintime .. inet_peer_gc_maxtime
* interval depending on the total number of entries (more entries,
* less interval). */
- if (peers.total >= inet_peer_threshold)
+ 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 *
- peers.total / inet_peer_threshold * HZ;
+ total / inet_peer_threshold * HZ;
add_timer(&peer_periodic_timer);
}
--
1.7.3.2
--
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