mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 19:00:25 +00:00
[IPV4]: fib_trie root-node expansion
The patch below introduces special thresholds to keep root node in the trie large. This gives a flatter tree at the cost of a modest memory increase. Overall it seems to be gain and this was also proposed by one the authors of the paper in recent a seminar. Main table after loading 123 k routes. Aver depth: 3.30 Max depth: 9 Root-node size 12 bits Total size: 4044 kB With the patch: Aver depth: 2.78 Max depth: 8 Root-node size 15 bits Total size: 4150 kB An increase of 8-10% was seen in forwading performance for an rDoS attack. Signed-off-by: Robert Olsson <robert.olsson@its.uu.se> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
parent
87bf9c97b4
commit
e6308be85a
1 changed files with 21 additions and 2 deletions
|
@ -286,6 +286,8 @@ static inline void check_tnode(const struct tnode *tn)
|
|||
|
||||
static int halve_threshold = 25;
|
||||
static int inflate_threshold = 50;
|
||||
static int halve_threshold_root = 15;
|
||||
static int inflate_threshold_root = 25;
|
||||
|
||||
|
||||
static void __alias_free_mem(struct rcu_head *head)
|
||||
|
@ -449,6 +451,8 @@ static struct node *resize(struct trie *t, struct tnode *tn)
|
|||
int i;
|
||||
int err = 0;
|
||||
struct tnode *old_tn;
|
||||
int inflate_threshold_use;
|
||||
int halve_threshold_use;
|
||||
|
||||
if (!tn)
|
||||
return NULL;
|
||||
|
@ -541,10 +545,17 @@ static struct node *resize(struct trie *t, struct tnode *tn)
|
|||
|
||||
check_tnode(tn);
|
||||
|
||||
/* Keep root node larger */
|
||||
|
||||
if(!tn->parent)
|
||||
inflate_threshold_use = inflate_threshold_root;
|
||||
else
|
||||
inflate_threshold_use = inflate_threshold;
|
||||
|
||||
err = 0;
|
||||
while ((tn->full_children > 0 &&
|
||||
50 * (tn->full_children + tnode_child_length(tn) - tn->empty_children) >=
|
||||
inflate_threshold * tnode_child_length(tn))) {
|
||||
inflate_threshold_use * tnode_child_length(tn))) {
|
||||
|
||||
old_tn = tn;
|
||||
tn = inflate(t, tn);
|
||||
|
@ -564,10 +575,18 @@ static struct node *resize(struct trie *t, struct tnode *tn)
|
|||
* node is above threshold.
|
||||
*/
|
||||
|
||||
|
||||
/* Keep root node larger */
|
||||
|
||||
if(!tn->parent)
|
||||
halve_threshold_use = halve_threshold_root;
|
||||
else
|
||||
halve_threshold_use = halve_threshold;
|
||||
|
||||
err = 0;
|
||||
while (tn->bits > 1 &&
|
||||
100 * (tnode_child_length(tn) - tn->empty_children) <
|
||||
halve_threshold * tnode_child_length(tn)) {
|
||||
halve_threshold_use * tnode_child_length(tn)) {
|
||||
|
||||
old_tn = tn;
|
||||
tn = halve(t, tn);
|
||||
|
|
Loading…
Reference in a new issue