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authorEric Dumazet <dada1@cosmosbay.com>2008-01-18 04:30:21 -0800
committerDavid S. Miller <davem@davemloft.net>2008-01-20 20:31:39 -0800
commit8d3f099abe25c21670cb5728178a1f286952782d (patch)
tree074339fd500a3af4f89cab67c0a90bae81bc93a7 /net/ipv4/fib_hash.c
parent49d85c502ec5e6d5998c1a04394c5b24e8f7d32d (diff)
downloadlinux-8d3f099abe25c21670cb5728178a1f286952782d.tar.bz2
[IPV4] FIB_HASH : Avoid unecessary loop in fn_hash_dump_zone()
I noticed "ip route list" was slower than "cat /proc/net/route" on a machine with a full Internet routing table (214392 entries : Special thanks to Robert ;) ) This is similar to problem reported in commit d8c9283089287341c85a0a69de32c2287a990e71 ("[IPV4] ROUTE: ip_rt_dump() is unecessary slow") Fix is to avoid scanning the begining of fz_hash table, but directly seek to the right offset. Before patch : time ip route >/tmp/ROUTE real 0m1.285s user 0m0.712s sys 0m0.436s After patch # time ip route >/tmp/ROUTE real 0m0.835s user 0m0.692s sys 0m0.124s Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/fib_hash.c')
-rw-r--r--net/ipv4/fib_hash.c20
1 files changed, 9 insertions, 11 deletions
diff --git a/net/ipv4/fib_hash.c b/net/ipv4/fib_hash.c
index 99071d79c5e7..0dfee27cfbcd 100644
--- a/net/ipv4/fib_hash.c
+++ b/net/ipv4/fib_hash.c
@@ -721,19 +721,18 @@ fn_hash_dump_zone(struct sk_buff *skb, struct netlink_callback *cb,
{
int h, s_h;
+ if (fz->fz_hash == NULL)
+ return skb->len;
s_h = cb->args[3];
- for (h=0; h < fz->fz_divisor; h++) {
- if (h < s_h) continue;
- if (h > s_h)
- memset(&cb->args[4], 0,
- sizeof(cb->args) - 4*sizeof(cb->args[0]));
- if (fz->fz_hash == NULL ||
- hlist_empty(&fz->fz_hash[h]))
+ for (h = s_h; h < fz->fz_divisor; h++) {
+ if (hlist_empty(&fz->fz_hash[h]))
continue;
- if (fn_hash_dump_bucket(skb, cb, tb, fz, &fz->fz_hash[h])<0) {
+ if (fn_hash_dump_bucket(skb, cb, tb, fz, &fz->fz_hash[h]) < 0) {
cb->args[3] = h;
return -1;
}
+ memset(&cb->args[4], 0,
+ sizeof(cb->args) - 4*sizeof(cb->args[0]));
}
cb->args[3] = h;
return skb->len;
@@ -749,14 +748,13 @@ static int fn_hash_dump(struct fib_table *tb, struct sk_buff *skb, struct netlin
read_lock(&fib_hash_lock);
for (fz = table->fn_zone_list, m=0; fz; fz = fz->fz_next, m++) {
if (m < s_m) continue;
- if (m > s_m)
- memset(&cb->args[3], 0,
- sizeof(cb->args) - 3*sizeof(cb->args[0]));
if (fn_hash_dump_zone(skb, cb, tb, fz) < 0) {
cb->args[2] = m;
read_unlock(&fib_hash_lock);
return -1;
}
+ memset(&cb->args[3], 0,
+ sizeof(cb->args) - 3*sizeof(cb->args[0]));
}
read_unlock(&fib_hash_lock);
cb->args[2] = m;