| Message ID | 20240925212942.3784786-1-alexandre.ferrieux@orange.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net] ipv4: avoid quadratic behavior in FIB insertion of common address | expand |
On Wed, Sep 25, 2024 at 11:29 PM Alexandre Ferrieux <alexandre.ferrieux@gmail.com> wrote: > > Mix netns into all IPv4 FIB hashes to avoid massive collision when > inserting the same address in many netns. > > Signed-off-by: Alexandre Ferrieux <alexandre.ferrieux@orange.com> I think this targets net-next tree, which re-opens next week. > --- > net/ipv4/fib_semantics.c | 8 +++++--- > 1 file changed, 5 insertions(+), 3 deletions(-) > > diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c > index ba2df3d2ac15..89fa8fd1a4a5 100644 > --- a/net/ipv4/fib_semantics.c > +++ b/net/ipv4/fib_semantics.c > @@ -347,10 +347,12 @@ static unsigned int fib_info_hashfn_1(int init_val, u8 protocol, u8 scope, > return val; > } > > -static unsigned int fib_info_hashfn_result(unsigned int val) > +static unsigned int fib_info_hashfn_result(struct net *net, unsigned int val) This can be 'const struct net *net' > { > unsigned int mask = (fib_info_hash_size - 1); mask can be deleted, see below. > > + val ^= net_hash_mix(net); > + > return (val ^ (val >> 7) ^ (val >> 12)) & mask; Please replace this legacy stuff with something more generic : return hash_32(val ^ net_hash_mix(net), fib_info_hash_bits); > } > > @@ -370,7 +372,7 @@ static inline unsigned int fib_info_hashfn(struct fib_info *fi) > } endfor_nexthops(fi) > } >
diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c index ba2df3d2ac15..89fa8fd1a4a5 100644 --- a/net/ipv4/fib_semantics.c +++ b/net/ipv4/fib_semantics.c @@ -347,10 +347,12 @@ static unsigned int fib_info_hashfn_1(int init_val, u8 protocol, u8 scope, return val; } -static unsigned int fib_info_hashfn_result(unsigned int val) +static unsigned int fib_info_hashfn_result(struct net *net, unsigned int val) { unsigned int mask = (fib_info_hash_size - 1); + val ^= net_hash_mix(net); + return (val ^ (val >> 7) ^ (val >> 12)) & mask; } @@ -370,7 +372,7 @@ static inline unsigned int fib_info_hashfn(struct fib_info *fi) } endfor_nexthops(fi) } - return fib_info_hashfn_result(val); + return fib_info_hashfn_result(fi->fib_net, val); } /* no metrics, only nexthop id */ @@ -385,7 +387,7 @@ static struct fib_info *fib_find_info_nh(struct net *net, cfg->fc_protocol, cfg->fc_scope, (__force u32)cfg->fc_prefsrc, cfg->fc_priority); - hash = fib_info_hashfn_result(hash); + hash = fib_info_hashfn_result(net, hash); head = &fib_info_hash[hash]; hlist_for_each_entry(fi, head, fib_hash) {
Mix netns into all IPv4 FIB hashes to avoid massive collision when inserting the same address in many netns. Signed-off-by: Alexandre Ferrieux <alexandre.ferrieux@orange.com> --- net/ipv4/fib_semantics.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)