17afb853ee
also refresh generic patches for 3.14, 3.18, 3.19 and 4.0 targets might need a minor refresh as well, however, it looks like everything still applies cleanly with occasional small offsets. Signed-off-by: Daniel Golle <daniel@makrotopia.org> SVN-Revision: 44876
345 lines
10 KiB
Diff
345 lines
10 KiB
Diff
From: Alexander Duyck <alexander.h.duyck@redhat.com>
|
|
Date: Wed, 31 Dec 2014 10:56:55 -0800
|
|
Subject: [PATCH] fib_trie: inflate/halve nodes in a more RCU friendly
|
|
way
|
|
|
|
This change pulls the node_set_parent functionality out of put_child_reorg
|
|
and instead leaves that to the function to take care of as well. By doing
|
|
this we can fully construct the new cluster of tnodes and all of the
|
|
pointers out of it before we start routing pointers into it.
|
|
|
|
I am suspecting this will likely fix some concurency issues though I don't
|
|
have a good test to show as such.
|
|
|
|
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
|
|
@@ -391,8 +391,6 @@ static void put_child(struct tnode *tn,
|
|
else if (!wasfull && isfull)
|
|
tn->full_children++;
|
|
|
|
- node_set_parent(n, tn);
|
|
-
|
|
rcu_assign_pointer(tn->child[i], n);
|
|
}
|
|
|
|
@@ -436,10 +434,8 @@ static void tnode_free(struct tnode *tn)
|
|
|
|
static int inflate(struct trie *t, struct tnode *oldtnode)
|
|
{
|
|
- unsigned long olen = tnode_child_length(oldtnode);
|
|
- struct tnode *tp = node_parent(oldtnode);
|
|
- struct tnode *tn;
|
|
- unsigned long i;
|
|
+ struct tnode *inode, *node0, *node1, *tn, *tp;
|
|
+ unsigned long i, j, k;
|
|
t_key m;
|
|
|
|
pr_debug("In inflate\n");
|
|
@@ -448,43 +444,13 @@ static int inflate(struct trie *t, struc
|
|
if (!tn)
|
|
return -ENOMEM;
|
|
|
|
- /*
|
|
- * Preallocate and store tnodes before the actual work so we
|
|
- * don't get into an inconsistent state if memory allocation
|
|
- * fails. In case of failure we return the oldnode and inflate
|
|
- * of tnode is ignored.
|
|
+ /* Assemble all of the pointers in our cluster, in this case that
|
|
+ * represents all of the pointers out of our allocated nodes that
|
|
+ * point to existing tnodes and the links between our allocated
|
|
+ * nodes.
|
|
*/
|
|
- for (i = 0, m = 1u << tn->pos; i < olen; i++) {
|
|
- struct tnode *inode = tnode_get_child(oldtnode, i);
|
|
-
|
|
- if (tnode_full(oldtnode, inode) && (inode->bits > 1)) {
|
|
- struct tnode *left, *right;
|
|
-
|
|
- left = tnode_new(inode->key & ~m, inode->pos,
|
|
- inode->bits - 1);
|
|
- if (!left)
|
|
- goto nomem;
|
|
- tnode_free_append(tn, left);
|
|
-
|
|
- right = tnode_new(inode->key | m, inode->pos,
|
|
- inode->bits - 1);
|
|
-
|
|
- if (!right)
|
|
- goto nomem;
|
|
- tnode_free_append(tn, right);
|
|
-
|
|
- put_child(tn, 2*i, left);
|
|
- put_child(tn, 2*i+1, right);
|
|
- }
|
|
- }
|
|
-
|
|
- /* prepare oldtnode to be freed */
|
|
- tnode_free_init(oldtnode);
|
|
-
|
|
- for (i = 0; i < olen; i++) {
|
|
- struct tnode *inode = tnode_get_child(oldtnode, i);
|
|
- struct tnode *left, *right;
|
|
- unsigned long size, j;
|
|
+ for (i = tnode_child_length(oldtnode), m = 1u << tn->pos; i;) {
|
|
+ inode = tnode_get_child(oldtnode, --i);
|
|
|
|
/* An empty child */
|
|
if (inode == NULL)
|
|
@@ -496,65 +462,99 @@ static int inflate(struct trie *t, struc
|
|
continue;
|
|
}
|
|
|
|
- /* drop the node in the old tnode free list */
|
|
- tnode_free_append(oldtnode, inode);
|
|
-
|
|
/* An internal node with two children */
|
|
if (inode->bits == 1) {
|
|
- put_child(tn, 2*i, rtnl_dereference(inode->child[0]));
|
|
- put_child(tn, 2*i+1, rtnl_dereference(inode->child[1]));
|
|
+ put_child(tn, 2 * i + 1, tnode_get_child(inode, 1));
|
|
+ put_child(tn, 2 * i, tnode_get_child(inode, 0));
|
|
continue;
|
|
}
|
|
|
|
- /* An internal node with more than two children */
|
|
-
|
|
/* We will replace this node 'inode' with two new
|
|
- * ones, 'left' and 'right', each with half of the
|
|
+ * ones, 'node0' and 'node1', each with half of the
|
|
* original children. The two new nodes will have
|
|
* a position one bit further down the key and this
|
|
* means that the "significant" part of their keys
|
|
* (see the discussion near the top of this file)
|
|
* will differ by one bit, which will be "0" in
|
|
- * left's key and "1" in right's key. Since we are
|
|
+ * node0's key and "1" in node1's key. Since we are
|
|
* moving the key position by one step, the bit that
|
|
* we are moving away from - the bit at position
|
|
- * (inode->pos) - is the one that will differ between
|
|
- * left and right. So... we synthesize that bit in the
|
|
- * two new keys.
|
|
- * The mask 'm' below will be a single "one" bit at
|
|
- * the position (inode->pos)
|
|
+ * (tn->pos) - is the one that will differ between
|
|
+ * node0 and node1. So... we synthesize that bit in the
|
|
+ * two new keys.
|
|
*/
|
|
+ node1 = tnode_new(inode->key | m, inode->pos, inode->bits - 1);
|
|
+ if (!node1)
|
|
+ goto nomem;
|
|
+ tnode_free_append(tn, node1);
|
|
+
|
|
+ node0 = tnode_new(inode->key & ~m, inode->pos, inode->bits - 1);
|
|
+ if (!node0)
|
|
+ goto nomem;
|
|
+ tnode_free_append(tn, node0);
|
|
+
|
|
+ /* populate child pointers in new nodes */
|
|
+ for (k = tnode_child_length(inode), j = k / 2; j;) {
|
|
+ put_child(node1, --j, tnode_get_child(inode, --k));
|
|
+ put_child(node0, j, tnode_get_child(inode, j));
|
|
+ put_child(node1, --j, tnode_get_child(inode, --k));
|
|
+ put_child(node0, j, tnode_get_child(inode, j));
|
|
+ }
|
|
+
|
|
+ /* link new nodes to parent */
|
|
+ NODE_INIT_PARENT(node1, tn);
|
|
+ NODE_INIT_PARENT(node0, tn);
|
|
+
|
|
+ /* link parent to nodes */
|
|
+ put_child(tn, 2 * i + 1, node1);
|
|
+ put_child(tn, 2 * i, node0);
|
|
+ }
|
|
+
|
|
+ /* setup the parent pointer into and out of this node */
|
|
+ tp = node_parent(oldtnode);
|
|
+ NODE_INIT_PARENT(tn, tp);
|
|
+ put_child_root(tp, t, tn->key, tn);
|
|
|
|
- /* Use the old key, but set the new significant
|
|
- * bit to zero.
|
|
- */
|
|
+ /* prepare oldtnode to be freed */
|
|
+ tnode_free_init(oldtnode);
|
|
|
|
- left = tnode_get_child(tn, 2*i);
|
|
- put_child(tn, 2*i, NULL);
|
|
+ /* update all child nodes parent pointers to route to us */
|
|
+ for (i = tnode_child_length(oldtnode); i;) {
|
|
+ inode = tnode_get_child(oldtnode, --i);
|
|
|
|
- BUG_ON(!left);
|
|
+ /* A leaf or an internal node with skipped bits */
|
|
+ if (!tnode_full(oldtnode, inode)) {
|
|
+ node_set_parent(inode, tn);
|
|
+ continue;
|
|
+ }
|
|
|
|
- right = tnode_get_child(tn, 2*i+1);
|
|
- put_child(tn, 2*i+1, NULL);
|
|
+ /* drop the node in the old tnode free list */
|
|
+ tnode_free_append(oldtnode, inode);
|
|
|
|
- BUG_ON(!right);
|
|
+ /* fetch new nodes */
|
|
+ node1 = tnode_get_child(tn, 2 * i + 1);
|
|
+ node0 = tnode_get_child(tn, 2 * i);
|
|
|
|
- size = tnode_child_length(left);
|
|
- for (j = 0; j < size; j++) {
|
|
- put_child(left, j, rtnl_dereference(inode->child[j]));
|
|
- put_child(right, j, rtnl_dereference(inode->child[j + size]));
|
|
+ /* bits == 1 then node0 and node1 represent inode's children */
|
|
+ if (inode->bits == 1) {
|
|
+ node_set_parent(node1, tn);
|
|
+ node_set_parent(node0, tn);
|
|
+ continue;
|
|
}
|
|
|
|
- put_child(tn, 2 * i, left);
|
|
- put_child(tn, 2 * i + 1, right);
|
|
+ /* update parent pointers in child node's children */
|
|
+ for (k = tnode_child_length(inode), j = k / 2; j;) {
|
|
+ node_set_parent(tnode_get_child(inode, --k), node1);
|
|
+ node_set_parent(tnode_get_child(inode, --j), node0);
|
|
+ node_set_parent(tnode_get_child(inode, --k), node1);
|
|
+ node_set_parent(tnode_get_child(inode, --j), node0);
|
|
+ }
|
|
|
|
/* resize child nodes */
|
|
- resize(t, left);
|
|
- resize(t, right);
|
|
+ resize(t, node1);
|
|
+ resize(t, node0);
|
|
}
|
|
|
|
- put_child_root(tp, t, tn->key, tn);
|
|
-
|
|
/* we completed without error, prepare to free old node */
|
|
tnode_free(oldtnode);
|
|
return 0;
|
|
@@ -566,10 +566,8 @@ nomem:
|
|
|
|
static int halve(struct trie *t, struct tnode *oldtnode)
|
|
{
|
|
- unsigned long olen = tnode_child_length(oldtnode);
|
|
- struct tnode *tp = node_parent(oldtnode);
|
|
- struct tnode *tn, *left, *right;
|
|
- int i;
|
|
+ struct tnode *tn, *tp, *inode, *node0, *node1;
|
|
+ unsigned long i;
|
|
|
|
pr_debug("In halve\n");
|
|
|
|
@@ -577,68 +575,64 @@ static int halve(struct trie *t, struct
|
|
if (!tn)
|
|
return -ENOMEM;
|
|
|
|
- /*
|
|
- * Preallocate and store tnodes before the actual work so we
|
|
- * don't get into an inconsistent state if memory allocation
|
|
- * fails. In case of failure we return the oldnode and halve
|
|
- * of tnode is ignored.
|
|
+ /* Assemble all of the pointers in our cluster, in this case that
|
|
+ * represents all of the pointers out of our allocated nodes that
|
|
+ * point to existing tnodes and the links between our allocated
|
|
+ * nodes.
|
|
*/
|
|
+ for (i = tnode_child_length(oldtnode); i;) {
|
|
+ node1 = tnode_get_child(oldtnode, --i);
|
|
+ node0 = tnode_get_child(oldtnode, --i);
|
|
|
|
- for (i = 0; i < olen; i += 2) {
|
|
- left = tnode_get_child(oldtnode, i);
|
|
- right = tnode_get_child(oldtnode, i+1);
|
|
+ /* At least one of the children is empty */
|
|
+ if (!node1 || !node0) {
|
|
+ put_child(tn, i / 2, node1 ? : node0);
|
|
+ continue;
|
|
+ }
|
|
|
|
/* Two nonempty children */
|
|
- if (left && right) {
|
|
- struct tnode *newn;
|
|
-
|
|
- newn = tnode_new(left->key, oldtnode->pos, 1);
|
|
- if (!newn) {
|
|
- tnode_free(tn);
|
|
- return -ENOMEM;
|
|
- }
|
|
- tnode_free_append(tn, newn);
|
|
-
|
|
- put_child(tn, i/2, newn);
|
|
+ inode = tnode_new(node0->key, oldtnode->pos, 1);
|
|
+ if (!inode) {
|
|
+ tnode_free(tn);
|
|
+ return -ENOMEM;
|
|
}
|
|
+ tnode_free_append(tn, inode);
|
|
|
|
+ /* initialize pointers out of node */
|
|
+ put_child(inode, 1, node1);
|
|
+ put_child(inode, 0, node0);
|
|
+ NODE_INIT_PARENT(inode, tn);
|
|
+
|
|
+ /* link parent to node */
|
|
+ put_child(tn, i / 2, inode);
|
|
}
|
|
|
|
+ /* setup the parent pointer out of and back into this node */
|
|
+ tp = node_parent(oldtnode);
|
|
+ NODE_INIT_PARENT(tn, tp);
|
|
+ put_child_root(tp, t, tn->key, tn);
|
|
+
|
|
/* prepare oldtnode to be freed */
|
|
tnode_free_init(oldtnode);
|
|
|
|
- for (i = 0; i < olen; i += 2) {
|
|
- struct tnode *newBinNode;
|
|
-
|
|
- left = tnode_get_child(oldtnode, i);
|
|
- right = tnode_get_child(oldtnode, i+1);
|
|
-
|
|
- /* At least one of the children is empty */
|
|
- if (left == NULL) {
|
|
- if (right == NULL) /* Both are empty */
|
|
- continue;
|
|
- put_child(tn, i/2, right);
|
|
- continue;
|
|
- }
|
|
-
|
|
- if (right == NULL) {
|
|
- put_child(tn, i/2, left);
|
|
+ /* update all of the child parent pointers */
|
|
+ for (i = tnode_child_length(tn); i;) {
|
|
+ inode = tnode_get_child(tn, --i);
|
|
+
|
|
+ /* only new tnodes will be considered "full" nodes */
|
|
+ if (!tnode_full(tn, inode)) {
|
|
+ node_set_parent(inode, tn);
|
|
continue;
|
|
}
|
|
|
|
/* Two nonempty children */
|
|
- newBinNode = tnode_get_child(tn, i/2);
|
|
- put_child(newBinNode, 0, left);
|
|
- put_child(newBinNode, 1, right);
|
|
-
|
|
- put_child(tn, i / 2, newBinNode);
|
|
+ node_set_parent(tnode_get_child(inode, 1), inode);
|
|
+ node_set_parent(tnode_get_child(inode, 0), inode);
|
|
|
|
/* resize child node */
|
|
- resize(t, newBinNode);
|
|
+ resize(t, inode);
|
|
}
|
|
|
|
- put_child_root(tp, t, tn->key, tn);
|
|
-
|
|
/* all pointers should be clean so we are done */
|
|
tnode_free(oldtnode);
|
|
|