diff options
| author | Ido Schimmel <idosch@mellanox.com> | 2018-01-09 17:40:27 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-01-10 23:14:44 +0300 |
| commit | 3d709f69a3e749f4d1c195dab499df8ab66e25a8 (patch) | |
| tree | fe11da750ce221ccc7d2e01eec2afc1badb7c415 /net/ipv6 | |
| parent | 7696c06a189c0f1f4d0a7e49e28d10e1050ec529 (diff) | |
| download | linux-3d709f69a3e749f4d1c195dab499df8ab66e25a8.tar.xz | |
ipv6: Use hash-threshold instead of modulo-N
Now that each nexthop stores its region boundary in the multipath hash
function's output space, we can use hash-threshold instead of modulo-N
in multipath selection.
This reduces the number of checks we need to perform during lookup, as
dead and linkdown nexthops are assigned a negative region boundary. In
addition, in contrast to modulo-N, only flows near region boundaries are
affected when a nexthop is added or removed.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6')
| -rw-r--r-- | net/ipv6/route.c | 36 |
1 files changed, 13 insertions, 23 deletions
diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 09e8e10b101d..7837b8c754a3 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -455,7 +455,6 @@ static struct rt6_info *rt6_multipath_select(struct rt6_info *match, int strict) { struct rt6_info *sibling, *next_sibling; - int route_choosen; /* We might have already computed the hash for ICMPv6 errors. In such * case it will always be non-zero. Otherwise now is the time to do it. @@ -463,28 +462,19 @@ static struct rt6_info *rt6_multipath_select(struct rt6_info *match, if (!fl6->mp_hash) fl6->mp_hash = rt6_multipath_hash(fl6, NULL); - route_choosen = fl6->mp_hash % (match->rt6i_nsiblings + 1); - /* Don't change the route, if route_choosen == 0 - * (siblings does not include ourself) - */ - if (route_choosen) - list_for_each_entry_safe(sibling, next_sibling, - &match->rt6i_siblings, rt6i_siblings) { - route_choosen--; - if (route_choosen == 0) { - struct inet6_dev *idev = sibling->rt6i_idev; - - if (sibling->rt6i_nh_flags & RTNH_F_DEAD) - break; - if (sibling->rt6i_nh_flags & RTNH_F_LINKDOWN && - idev->cnf.ignore_routes_with_linkdown) - break; - if (rt6_score_route(sibling, oif, strict) < 0) - break; - match = sibling; - break; - } - } + if (fl6->mp_hash <= atomic_read(&match->rt6i_nh_upper_bound)) + return match; + + list_for_each_entry_safe(sibling, next_sibling, &match->rt6i_siblings, + rt6i_siblings) { + if (fl6->mp_hash > atomic_read(&sibling->rt6i_nh_upper_bound)) + continue; + if (rt6_score_route(sibling, oif, strict) < 0) + break; + match = sibling; + break; + } + return match; } |