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From: Alexander Duyck <alexander.h.duyck@redhat.com>
Date: Wed, 31 Dec 2014 10:55:41 -0800
Subject: [PATCH] fib_trie: Merge tnode_free and leaf_free into node_free
Both the leaf and the tnode had an rcu_head in them, but they had them in
slightly different places. Since we now have them in the same spot and
know that any node with bits == 0 is a leaf and the rest are either vmalloc
or kmalloc tnodes depending on the value of bits it makes it easy to combine
the functions and reduce overhead.
In addition I have taken advantage of the rcu_head pointer to go ahead and
put together a simple linked list instead of using the tnode pointer as
this way we can merge either type of structure for freeing.
Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -95,15 +95,17 @@ struct tnode {
unsigned char bits; /* 2log(KEYLENGTH) bits needed */
unsigned char pos; /* 2log(KEYLENGTH) bits needed */
struct tnode __rcu *parent;
- union {
- struct rcu_head rcu;
- struct tnode *tnode_free;
- };
+ struct rcu_head rcu;
+ /* everything above this comment must be the same as rt_trie_node */
unsigned int full_children; /* KEYLENGTH bits needed */
unsigned int empty_children; /* KEYLENGTH bits needed */
struct rt_trie_node __rcu *child[0];
};
+/* This struct represents the shared bits between tnode and leaf. If any
+ * ordering is changed here is must also be updated in tnode and leaf as
+ * well.
+ */
struct rt_trie_node {
t_key key;
unsigned char bits;
@@ -118,6 +120,7 @@ struct leaf {
unsigned char pos;
struct tnode __rcu *parent;
struct rcu_head rcu;
+ /* everything above this comment must be the same as rt_trie_node */
struct hlist_head list;
};
@@ -163,7 +166,7 @@ static struct rt_trie_node *resize(struc
static struct tnode *inflate(struct trie *t, struct tnode *tn);
static struct tnode *halve(struct trie *t, struct tnode *tn);
/* tnodes to free after resize(); protected by RTNL */
-static struct tnode *tnode_free_head;
+static struct callback_head *tnode_free_head;
static size_t tnode_free_size;
/*
@@ -336,17 +339,23 @@ static inline void alias_free_mem_rcu(st
call_rcu(&fa->rcu, __alias_free_mem);
}
-static void __leaf_free_rcu(struct rcu_head *head)
-{
- struct leaf *l = container_of(head, struct leaf, rcu);
- kmem_cache_free(trie_leaf_kmem, l);
-}
+#define TNODE_KMALLOC_MAX \
+ ilog2((PAGE_SIZE - sizeof(struct tnode)) / sizeof(struct rt_trie_node *))
-static inline void free_leaf(struct leaf *l)
+static void __node_free_rcu(struct rcu_head *head)
{
- call_rcu(&l->rcu, __leaf_free_rcu);
+ struct rt_trie_node *n = container_of(head, struct rt_trie_node, rcu);
+
+ if (IS_LEAF(n))
+ kmem_cache_free(trie_leaf_kmem, n);
+ else if (n->bits <= TNODE_KMALLOC_MAX)
+ kfree(n);
+ else
+ vfree(n);
}
+#define node_free(n) call_rcu(&n->rcu, __node_free_rcu)
+
static inline void free_leaf_info(struct leaf_info *leaf)
{
kfree_rcu(leaf, rcu);
@@ -360,43 +369,24 @@ static struct tnode *tnode_alloc(size_t
return vzalloc(size);
}
-static void __tnode_free_rcu(struct rcu_head *head)
-{
- struct tnode *tn = container_of(head, struct tnode, rcu);
- size_t size = sizeof(struct tnode) +
- (sizeof(struct rt_trie_node *) << tn->bits);
-
- if (size <= PAGE_SIZE)
- kfree(tn);
- else
- vfree(tn);
-}
-
-static inline void tnode_free(struct tnode *tn)
-{
- if (IS_LEAF(tn))
- free_leaf((struct leaf *) tn);
- else
- call_rcu(&tn->rcu, __tnode_free_rcu);
-}
-
static void tnode_free_safe(struct tnode *tn)
{
BUG_ON(IS_LEAF(tn));
- tn->tnode_free = tnode_free_head;
- tnode_free_head = tn;
- tnode_free_size += sizeof(struct tnode) +
- (sizeof(struct rt_trie_node *) << tn->bits);
+ tn->rcu.next = tnode_free_head;
+ tnode_free_head = &tn->rcu;
}
static void tnode_free_flush(void)
{
- struct tnode *tn;
+ struct callback_head *head;
+
+ while ((head = tnode_free_head)) {
+ struct tnode *tn = container_of(head, struct tnode, rcu);
+
+ tnode_free_head = head->next;
+ tnode_free_size += offsetof(struct tnode, child[1 << tn->bits]);
- while ((tn = tnode_free_head)) {
- tnode_free_head = tn->tnode_free;
- tn->tnode_free = NULL;
- tnode_free(tn);
+ node_free(tn);
}
if (tnode_free_size >= PAGE_SIZE * sync_pages) {
@@ -437,7 +427,7 @@ static struct leaf_info *leaf_info_new(i
static struct tnode *tnode_new(t_key key, int pos, int bits)
{
- size_t sz = sizeof(struct tnode) + (sizeof(struct rt_trie_node *) << bits);
+ size_t sz = offsetof(struct tnode, child[1 << bits]);
struct tnode *tn = tnode_alloc(sz);
unsigned int shift = pos + bits;
@@ -666,15 +656,15 @@ no_children:
static void tnode_clean_free(struct tnode *tn)
{
+ struct rt_trie_node *tofree;
int i;
- struct tnode *tofree;
for (i = 0; i < tnode_child_length(tn); i++) {
- tofree = (struct tnode *)rtnl_dereference(tn->child[i]);
+ tofree = rtnl_dereference(tn->child[i]);
if (tofree)
- tnode_free(tofree);
+ node_free(tofree);
}
- tnode_free(tn);
+ node_free(tn);
}
static struct tnode *inflate(struct trie *t, struct tnode *tn)
@@ -717,7 +707,7 @@ static struct tnode *inflate(struct trie
inode->bits - 1);
if (!right) {
- tnode_free(left);
+ node_free(left);
goto nomem;
}
@@ -1068,7 +1058,7 @@ static struct list_head *fib_insert_node
li = leaf_info_new(plen);
if (!li) {
- free_leaf(l);
+ node_free(l);
return NULL;
}
@@ -1100,7 +1090,7 @@ static struct list_head *fib_insert_node
if (!tn) {
free_leaf_info(li);
- free_leaf(l);
+ node_free(l);
return NULL;
}
@@ -1580,7 +1570,7 @@ static void trie_leaf_remove(struct trie
} else
RCU_INIT_POINTER(t->trie, NULL);
- free_leaf(l);
+ node_free(l);
}
/*
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