linux/include/net/ip_fib.h, branch v3.6

ipv4: Cache routes in nexthop exception entries.

2012-07-31T22:02:02Z

Signed-off-by: David S. Miller

ipv4: percpu nh_rth_output cache

2012-07-31T21:41:39Z

Input path is mostly run under RCU and doesnt touch dst refcnt But output path on forwarding or UDP workloads hits badly dst refcount, and we have lot of false sharing, for example in ipv4_mtu() when reading rt->rt_pmtu Using a percpu cache for nh_rth_output gives a nice performance increase at a small cost. 24 udpflood test on my 24 cpu machine (dummy0 output device) (each process sends 1.000.000 udp frames, 24 processes are started) before : 5.24 s after : 2.06 s For reference, time on linux-3.5 : 6.60 s Signed-off-by: Eric Dumazet Tested-by: Alexander Duyck Signed-off-by: David S. Miller

ipv4: Restore old dst_free() behavior.

2012-07-31T21:41:38Z

commit 404e0a8b6a55 (net: ipv4: fix RCU races on dst refcounts) tried to solve a race but added a problem at device/fib dismantle time : We really want to call dst_free() as soon as possible, even if sockets still have dst in their cache. dst_release() calls in free_fib_info_rcu() are not welcomed. Root of the problem was that now we also cache output routes (in nh_rth_output), we must use call_rcu() instead of call_rcu_bh() in rt_free(), because output route lookups are done in process context. Based on feedback and initial patch from David Miller (adding another call_rcu_bh() call in fib, but it appears it was not the right fix) I left the inet_sk_rx_dst_set() helper and added __rcu attributes to nh_rth_output and nh_rth_input to better document what is going on in this code. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

ipv4: Cache input routes in fib_info nexthops.

2012-07-20T20:36:40Z

Caching input routes is slightly simpler than output routes, since we don't need to be concerned with nexthop exceptions. (locally destined, and routed packets, never trigger PMTU events or redirects that will be processed by us). However, we have to elide caching for the DIRECTSRC and non-zero itag cases. Signed-off-by: David S. Miller

ipv4: Cache output routes in fib_info nexthops.

2012-07-20T20:36:16Z

If we have an output route that lacks nexthop exceptions, we can cache it in the FIB info nexthop. Such routes will have DST_HOST cleared because such routes refer to a family of destinations, rather than just one. The sequence of the handling of exceptions during route lookup is adjusted to make the logic work properly. Before we allocate the route, we lookup the exception. Then we know if we will cache this route or not, and therefore whether DST_HOST should be set on the allocated route. Then we use DST_HOST to key off whether we should store the resulting route, during rt_set_nexthop(), in the FIB nexthop cache. With help from Eric Dumazet. Signed-off-by: David S. Miller

ipv4: use seqlock for nh_exceptions

2012-07-19T17:30:14Z

Use global seqlock for the nh_exceptions. Call fnhe_oldest with the right hash chain. Correct the diff value for dst_set_expires. v2: after suggestions from Eric Dumazet: * get rid of spin lock fnhe_lock, rearrange update_or_create_fnhe * continue daddr search in rt_bind_exception v3: * remove the daddr check before seqlock in rt_bind_exception * restart lookup in rt_bind_exception on detected seqlock change, as suggested by David Miller Signed-off-by: Julian Anastasov Signed-off-by: David S. Miller

ipv4: Add FIB nexthop exceptions.

2012-07-17T15:48:50Z

In a regime where we have subnetted route entries, we need a way to store persistent storage about destination specific learned values such as redirects and PMTU values. This is implemented here via nexthop exceptions. The initial implementation is a 2048 entry hash table with relaiming starting at chain length 5. A more sophisticated scheme can be devised if that proves necessary. Signed-off-by: David S. Miller

ipv4: Don't store a rule pointer in fib_result.

2012-07-13T15:21:29Z

We only use it to fetch the rule's tclassid, so just store the tclassid there instead. This also decreases the size of fib_result by a full 8 bytes on 64-bit. On 32-bits it's a wash. Signed-off-by: David S. Miller

ipv4: Remove tb_peers from fib_table.

2012-07-12T16:39:28Z

No longer used. Signed-off-by: David S. Miller

ipv4: Fix crashes in fib_rules_tclass().

2012-07-11T01:05:28Z

All paths assume, when CONFIG_IP_MULTIPLE_TABLES is enabled, that any successful call to fib_lookup() will initialize the fib_result->r value to something. We violated that expectation in the new fib_lookup() fast path. Reported-by: Or Gerlitz Tested-by: Eric Dumazet Tested-by: Greg Rose Signed-off-by: David S. Miller