c52475712e
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
251 lines
8.1 KiB
Diff
251 lines
8.1 KiB
Diff
From: Alexander Duyck <alexander.h.duyck@redhat.com>
|
|
Date: Wed, 31 Dec 2014 10:56:37 -0800
|
|
Subject: [PATCH] fib_trie: Add functions should_inflate and should_halve
|
|
|
|
This change pulls the logic for if we should inflate/halve the nodes out
|
|
into separate functions. It also addresses what I believe is a bug where 1
|
|
full node is all that is needed to keep a node from ever being halved.
|
|
|
|
Simple script to reproduce the issue:
|
|
modprobe dummy; ifconfig dummy0 up
|
|
for i in `seq 0 255`; do ifconfig dummy0:$i 10.0.${i}.1/24 up; done
|
|
ifconfig dummy0:256 10.0.255.33/16 up
|
|
for i in `seq 0 254`; do ifconfig dummy0:$i down; done
|
|
|
|
Results from /proc/net/fib_triestat
|
|
Before:
|
|
Local:
|
|
Aver depth: 3.00
|
|
Max depth: 4
|
|
Leaves: 17
|
|
Prefixes: 18
|
|
Internal nodes: 11
|
|
1: 8 2: 2 10: 1
|
|
Pointers: 1048
|
|
Null ptrs: 1021
|
|
Total size: 11 kB
|
|
After:
|
|
Local:
|
|
Aver depth: 3.41
|
|
Max depth: 5
|
|
Leaves: 17
|
|
Prefixes: 18
|
|
Internal nodes: 12
|
|
1: 8 2: 3 3: 1
|
|
Pointers: 36
|
|
Null ptrs: 8
|
|
Total size: 3 kB
|
|
|
|
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
|
|
@@ -647,12 +647,94 @@ nomem:
|
|
return ERR_PTR(-ENOMEM);
|
|
}
|
|
|
|
+/* From "Implementing a dynamic compressed trie" by Stefan Nilsson of
|
|
+ * the Helsinki University of Technology and Matti Tikkanen of Nokia
|
|
+ * Telecommunications, page 6:
|
|
+ * "A node is doubled if the ratio of non-empty children to all
|
|
+ * children in the *doubled* node is at least 'high'."
|
|
+ *
|
|
+ * 'high' in this instance is the variable 'inflate_threshold'. It
|
|
+ * is expressed as a percentage, so we multiply it with
|
|
+ * tnode_child_length() and instead of multiplying by 2 (since the
|
|
+ * child array will be doubled by inflate()) and multiplying
|
|
+ * the left-hand side by 100 (to handle the percentage thing) we
|
|
+ * multiply the left-hand side by 50.
|
|
+ *
|
|
+ * The left-hand side may look a bit weird: tnode_child_length(tn)
|
|
+ * - tn->empty_children is of course the number of non-null children
|
|
+ * in the current node. tn->full_children is the number of "full"
|
|
+ * children, that is non-null tnodes with a skip value of 0.
|
|
+ * All of those will be doubled in the resulting inflated tnode, so
|
|
+ * we just count them one extra time here.
|
|
+ *
|
|
+ * A clearer way to write this would be:
|
|
+ *
|
|
+ * to_be_doubled = tn->full_children;
|
|
+ * not_to_be_doubled = tnode_child_length(tn) - tn->empty_children -
|
|
+ * tn->full_children;
|
|
+ *
|
|
+ * new_child_length = tnode_child_length(tn) * 2;
|
|
+ *
|
|
+ * new_fill_factor = 100 * (not_to_be_doubled + 2*to_be_doubled) /
|
|
+ * new_child_length;
|
|
+ * if (new_fill_factor >= inflate_threshold)
|
|
+ *
|
|
+ * ...and so on, tho it would mess up the while () loop.
|
|
+ *
|
|
+ * anyway,
|
|
+ * 100 * (not_to_be_doubled + 2*to_be_doubled) / new_child_length >=
|
|
+ * inflate_threshold
|
|
+ *
|
|
+ * avoid a division:
|
|
+ * 100 * (not_to_be_doubled + 2*to_be_doubled) >=
|
|
+ * inflate_threshold * new_child_length
|
|
+ *
|
|
+ * expand not_to_be_doubled and to_be_doubled, and shorten:
|
|
+ * 100 * (tnode_child_length(tn) - tn->empty_children +
|
|
+ * tn->full_children) >= inflate_threshold * new_child_length
|
|
+ *
|
|
+ * expand new_child_length:
|
|
+ * 100 * (tnode_child_length(tn) - tn->empty_children +
|
|
+ * tn->full_children) >=
|
|
+ * inflate_threshold * tnode_child_length(tn) * 2
|
|
+ *
|
|
+ * shorten again:
|
|
+ * 50 * (tn->full_children + tnode_child_length(tn) -
|
|
+ * tn->empty_children) >= inflate_threshold *
|
|
+ * tnode_child_length(tn)
|
|
+ *
|
|
+ */
|
|
+static bool should_inflate(const struct tnode *tn)
|
|
+{
|
|
+ unsigned long used = tnode_child_length(tn);
|
|
+ unsigned long threshold = used;
|
|
+
|
|
+ /* Keep root node larger */
|
|
+ threshold *= node_parent(tn) ? inflate_threshold :
|
|
+ inflate_threshold_root;
|
|
+ used += tn->full_children;
|
|
+ used -= tn->empty_children;
|
|
+
|
|
+ return tn->pos && ((50 * used) >= threshold);
|
|
+}
|
|
+
|
|
+static bool should_halve(const struct tnode *tn)
|
|
+{
|
|
+ unsigned long used = tnode_child_length(tn);
|
|
+ unsigned long threshold = used;
|
|
+
|
|
+ /* Keep root node larger */
|
|
+ threshold *= node_parent(tn) ? halve_threshold :
|
|
+ halve_threshold_root;
|
|
+ used -= tn->empty_children;
|
|
+
|
|
+ return (tn->bits > 1) && ((100 * used) < threshold);
|
|
+}
|
|
+
|
|
#define MAX_WORK 10
|
|
static struct tnode *resize(struct trie *t, struct tnode *tn)
|
|
{
|
|
struct tnode *old_tn, *n = NULL;
|
|
- int inflate_threshold_use;
|
|
- int halve_threshold_use;
|
|
int max_work;
|
|
|
|
if (!tn)
|
|
@@ -668,86 +750,12 @@ static struct tnode *resize(struct trie
|
|
/* One child */
|
|
if (tn->empty_children == (tnode_child_length(tn) - 1))
|
|
goto one_child;
|
|
- /*
|
|
- * Double as long as the resulting node has a number of
|
|
- * nonempty nodes that are above the threshold.
|
|
- */
|
|
|
|
- /*
|
|
- * From "Implementing a dynamic compressed trie" by Stefan Nilsson of
|
|
- * the Helsinki University of Technology and Matti Tikkanen of Nokia
|
|
- * Telecommunications, page 6:
|
|
- * "A node is doubled if the ratio of non-empty children to all
|
|
- * children in the *doubled* node is at least 'high'."
|
|
- *
|
|
- * 'high' in this instance is the variable 'inflate_threshold'. It
|
|
- * is expressed as a percentage, so we multiply it with
|
|
- * tnode_child_length() and instead of multiplying by 2 (since the
|
|
- * child array will be doubled by inflate()) and multiplying
|
|
- * the left-hand side by 100 (to handle the percentage thing) we
|
|
- * multiply the left-hand side by 50.
|
|
- *
|
|
- * The left-hand side may look a bit weird: tnode_child_length(tn)
|
|
- * - tn->empty_children is of course the number of non-null children
|
|
- * in the current node. tn->full_children is the number of "full"
|
|
- * children, that is non-null tnodes with a skip value of 0.
|
|
- * All of those will be doubled in the resulting inflated tnode, so
|
|
- * we just count them one extra time here.
|
|
- *
|
|
- * A clearer way to write this would be:
|
|
- *
|
|
- * to_be_doubled = tn->full_children;
|
|
- * not_to_be_doubled = tnode_child_length(tn) - tn->empty_children -
|
|
- * tn->full_children;
|
|
- *
|
|
- * new_child_length = tnode_child_length(tn) * 2;
|
|
- *
|
|
- * new_fill_factor = 100 * (not_to_be_doubled + 2*to_be_doubled) /
|
|
- * new_child_length;
|
|
- * if (new_fill_factor >= inflate_threshold)
|
|
- *
|
|
- * ...and so on, tho it would mess up the while () loop.
|
|
- *
|
|
- * anyway,
|
|
- * 100 * (not_to_be_doubled + 2*to_be_doubled) / new_child_length >=
|
|
- * inflate_threshold
|
|
- *
|
|
- * avoid a division:
|
|
- * 100 * (not_to_be_doubled + 2*to_be_doubled) >=
|
|
- * inflate_threshold * new_child_length
|
|
- *
|
|
- * expand not_to_be_doubled and to_be_doubled, and shorten:
|
|
- * 100 * (tnode_child_length(tn) - tn->empty_children +
|
|
- * tn->full_children) >= inflate_threshold * new_child_length
|
|
- *
|
|
- * expand new_child_length:
|
|
- * 100 * (tnode_child_length(tn) - tn->empty_children +
|
|
- * tn->full_children) >=
|
|
- * inflate_threshold * tnode_child_length(tn) * 2
|
|
- *
|
|
- * shorten again:
|
|
- * 50 * (tn->full_children + tnode_child_length(tn) -
|
|
- * tn->empty_children) >= inflate_threshold *
|
|
- * tnode_child_length(tn)
|
|
- *
|
|
+ /* Double as long as the resulting node has a number of
|
|
+ * nonempty nodes that are above the threshold.
|
|
*/
|
|
-
|
|
- /* Keep root node larger */
|
|
-
|
|
- if (!node_parent(tn)) {
|
|
- inflate_threshold_use = inflate_threshold_root;
|
|
- halve_threshold_use = halve_threshold_root;
|
|
- } else {
|
|
- inflate_threshold_use = inflate_threshold;
|
|
- halve_threshold_use = halve_threshold;
|
|
- }
|
|
-
|
|
max_work = MAX_WORK;
|
|
- while ((tn->full_children > 0 && max_work-- &&
|
|
- 50 * (tn->full_children + tnode_child_length(tn)
|
|
- - tn->empty_children)
|
|
- >= inflate_threshold_use * tnode_child_length(tn))) {
|
|
-
|
|
+ while (should_inflate(tn) && max_work--) {
|
|
old_tn = tn;
|
|
tn = inflate(t, tn);
|
|
|
|
@@ -764,16 +772,11 @@ static struct tnode *resize(struct trie
|
|
if (max_work != MAX_WORK)
|
|
return tn;
|
|
|
|
- /*
|
|
- * Halve as long as the number of empty children in this
|
|
+ /* Halve as long as the number of empty children in this
|
|
* node is above threshold.
|
|
*/
|
|
-
|
|
max_work = MAX_WORK;
|
|
- while (tn->bits > 1 && max_work-- &&
|
|
- 100 * (tnode_child_length(tn) - tn->empty_children) <
|
|
- halve_threshold_use * tnode_child_length(tn)) {
|
|
-
|
|
+ while (should_halve(tn) && max_work--) {
|
|
old_tn = tn;
|
|
tn = halve(t, tn);
|
|
if (IS_ERR(tn)) {
|