fib_trie: Push tnode flushing down to inflate/halve
This change pushes the tnode freeing down into the inflate and halve functions. It makes more sense here as we have a better grasp of what is going on and when a given cluster of nodes is ready to be freed. I believe this may address a bug in the freeing logic as well. For some reason if the freelist got to a certain size we would call synchronize_rcu(). I'm assuming that what they meant to do is call synchronize_rcu() after they had handed off that much memory via call_rcu(). As such that is what I have updated the behavior to be. Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Alexander Duyck
David S. Miller
parent
ff181ed876
commit
fc86a93b46
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@ -147,8 +147,6 @@ struct trie {
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};
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static void resize(struct trie *t, struct tnode *tn);
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/* tnodes to free after resize(); protected by RTNL */
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static struct callback_head *tnode_free_head;
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static size_t tnode_free_size;
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/*
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@ -307,32 +305,6 @@ static struct tnode *tnode_alloc(size_t size)
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return vzalloc(size);
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}
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static void tnode_free_safe(struct tnode *tn)
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{
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BUG_ON(IS_LEAF(tn));
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tn->rcu.next = tnode_free_head;
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tnode_free_head = &tn->rcu;
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}
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static void tnode_free_flush(void)
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{
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struct callback_head *head;
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while ((head = tnode_free_head)) {
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struct tnode *tn = container_of(head, struct tnode, rcu);
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tnode_free_head = head->next;
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tnode_free_size += offsetof(struct tnode, child[1 << tn->bits]);
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node_free(tn);
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}
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if (tnode_free_size >= PAGE_SIZE * sync_pages) {
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tnode_free_size = 0;
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synchronize_rcu();
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}
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}
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static struct tnode *leaf_new(t_key key)
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{
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struct tnode *l = kmem_cache_alloc(trie_leaf_kmem, GFP_KERNEL);
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@ -433,17 +405,33 @@ static void put_child_root(struct tnode *tp, struct trie *t,
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rcu_assign_pointer(t->trie, n);
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}
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static void tnode_clean_free(struct tnode *tn)
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static inline void tnode_free_init(struct tnode *tn)
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{
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struct tnode *tofree;
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unsigned long i;
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tn->rcu.next = NULL;
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}
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for (i = 0; i < tnode_child_length(tn); i++) {
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tofree = tnode_get_child(tn, i);
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if (tofree)
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node_free(tofree);
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static inline void tnode_free_append(struct tnode *tn, struct tnode *n)
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{
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n->rcu.next = tn->rcu.next;
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tn->rcu.next = &n->rcu;
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}
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static void tnode_free(struct tnode *tn)
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{
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struct callback_head *head = &tn->rcu;
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while (head) {
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head = head->next;
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tnode_free_size += offsetof(struct tnode, child[1 << tn->bits]);
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node_free(tn);
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tn = container_of(head, struct tnode, rcu);
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}
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if (tnode_free_size >= PAGE_SIZE * sync_pages) {
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tnode_free_size = 0;
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synchronize_rcu();
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}
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node_free(tn);
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}
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static int inflate(struct trie *t, struct tnode *oldtnode)
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@ -476,20 +464,23 @@ static int inflate(struct trie *t, struct tnode *oldtnode)
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inode->bits - 1);
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if (!left)
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goto nomem;
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tnode_free_append(tn, left);
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right = tnode_new(inode->key | m, inode->pos,
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inode->bits - 1);
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if (!right) {
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node_free(left);
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if (!right)
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goto nomem;
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}
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tnode_free_append(tn, right);
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put_child(tn, 2*i, left);
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put_child(tn, 2*i+1, right);
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}
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}
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/* prepare oldtnode to be freed */
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tnode_free_init(oldtnode);
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for (i = 0; i < olen; i++) {
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struct tnode *inode = tnode_get_child(oldtnode, i);
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struct tnode *left, *right;
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@ -505,12 +496,13 @@ static int inflate(struct trie *t, struct tnode *oldtnode)
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continue;
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}
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/* drop the node in the old tnode free list */
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tnode_free_append(oldtnode, inode);
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/* An internal node with two children */
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if (inode->bits == 1) {
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put_child(tn, 2*i, rtnl_dereference(inode->child[0]));
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put_child(tn, 2*i+1, rtnl_dereference(inode->child[1]));
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tnode_free_safe(inode);
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continue;
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}
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@ -556,17 +548,19 @@ static int inflate(struct trie *t, struct tnode *oldtnode)
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put_child(tn, 2 * i, left);
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put_child(tn, 2 * i + 1, right);
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tnode_free_safe(inode);
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/* resize child nodes */
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resize(t, left);
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resize(t, right);
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}
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put_child_root(tp, t, tn->key, tn);
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tnode_free_safe(oldtnode);
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/* we completed without error, prepare to free old node */
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tnode_free(oldtnode);
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return 0;
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nomem:
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tnode_clean_free(tn);
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/* all pointers should be clean so we are done */
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tnode_free(tn);
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return -ENOMEM;
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}
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@ -599,17 +593,20 @@ static int halve(struct trie *t, struct tnode *oldtnode)
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struct tnode *newn;
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newn = tnode_new(left->key, oldtnode->pos, 1);
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if (!newn) {
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tnode_clean_free(tn);
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tnode_free(tn);
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return -ENOMEM;
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}
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tnode_free_append(tn, newn);
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put_child(tn, i/2, newn);
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}
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}
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/* prepare oldtnode to be freed */
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tnode_free_init(oldtnode);
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for (i = 0; i < olen; i += 2) {
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struct tnode *newBinNode;
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@ -636,11 +633,14 @@ static int halve(struct trie *t, struct tnode *oldtnode)
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put_child(tn, i / 2, newBinNode);
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/* resize child node */
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resize(t, newBinNode);
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}
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put_child_root(tp, t, tn->key, tn);
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tnode_free_safe(oldtnode);
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/* all pointers should be clean so we are done */
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tnode_free(oldtnode);
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return 0;
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}
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@ -798,7 +798,8 @@ static void resize(struct trie *t, struct tnode *tn)
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node_set_parent(n, tp);
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/* drop dead node */
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tnode_free_safe(tn);
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tnode_free_init(tn);
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tnode_free(tn);
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}
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}
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@ -884,16 +885,12 @@ static void trie_rebalance(struct trie *t, struct tnode *tn)
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while ((tp = node_parent(tn)) != NULL) {
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resize(t, tn);
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tnode_free_flush();
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tn = tp;
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}
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/* Handle last (top) tnode */
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if (IS_TNODE(tn))
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resize(t, tn);
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tnode_free_flush();
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}
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/* only used from updater-side */
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