netfilter: ipset: Introduce RCU locking in hash:* types
Three types of data need to be protected in the case of the hash types: a. The hash buckets: standard rcu pointer operations are used. b. The element blobs in the hash buckets are stored in an array and a bitmap is used for book-keeping to tell which elements in the array are used or free. c. Networks per cidr values and the cidr values themselves are stored in fix sized arrays and need no protection. The values are modified in such an order that in the worst case an element testing is repeated once with the same cidr value. The ipset hash approach uses arrays instead of lists and therefore is incompatible with rhashtable. Performance is tested by Jesper Dangaard Brouer: Simple drop in FORWARD ~~~~~~~~~~~~~~~~~~~~~~ Dropping via simple iptables net-mask match:: iptables -t raw -N simple || iptables -t raw -F simple iptables -t raw -I simple -s 198.18.0.0/15 -j DROP iptables -t raw -D PREROUTING -j simple iptables -t raw -I PREROUTING -j simple Drop performance in "raw": 11.3Mpps Generator: sending 12.2Mpps (tx:12264083 pps) Drop via original ipset in RAW table ~~~~~~~~~~~~~~~~~~~~~~~~~~~ Create a set with lots of elements:: sudo ./ipset destroy test echo "create test hash:ip hashsize 65536" > test.set for x in `seq 0 255`; do for y in `seq 0 255`; do echo "add test 198.18.$x.$y" >> test.set done done sudo ./ipset restore < test.set Dropping via ipset:: iptables -t raw -F iptables -t raw -N net198 || iptables -t raw -F net198 iptables -t raw -I net198 -m set --match-set test src -j DROP iptables -t raw -I PREROUTING -j net198 Drop performance in "raw" with ipset: 8Mpps Perf report numbers ipset drop in "raw":: + 24.65% ksoftirqd/1 [ip_set] [k] ip_set_test - 21.42% ksoftirqd/1 [kernel.kallsyms] [k] _raw_read_lock_bh - _raw_read_lock_bh + 99.88% ip_set_test - 19.42% ksoftirqd/1 [kernel.kallsyms] [k] _raw_read_unlock_bh - _raw_read_unlock_bh + 99.72% ip_set_test + 4.31% ksoftirqd/1 [ip_set_hash_ip] [k] hash_ip4_kadt + 2.27% ksoftirqd/1 [ixgbe] [k] ixgbe_fetch_rx_buffer + 2.18% ksoftirqd/1 [ip_tables] [k] ipt_do_table + 1.81% ksoftirqd/1 [ip_set_hash_ip] [k] hash_ip4_test + 1.61% ksoftirqd/1 [kernel.kallsyms] [k] __netif_receive_skb_core + 1.44% ksoftirqd/1 [kernel.kallsyms] [k] build_skb + 1.42% ksoftirqd/1 [kernel.kallsyms] [k] ip_rcv + 1.36% ksoftirqd/1 [kernel.kallsyms] [k] __local_bh_enable_ip + 1.16% ksoftirqd/1 [kernel.kallsyms] [k] dev_gro_receive + 1.09% ksoftirqd/1 [kernel.kallsyms] [k] __rcu_read_unlock + 0.96% ksoftirqd/1 [ixgbe] [k] ixgbe_clean_rx_irq + 0.95% ksoftirqd/1 [kernel.kallsyms] [k] __netdev_alloc_frag + 0.88% ksoftirqd/1 [kernel.kallsyms] [k] kmem_cache_alloc + 0.87% ksoftirqd/1 [xt_set] [k] set_match_v3 + 0.85% ksoftirqd/1 [kernel.kallsyms] [k] inet_gro_receive + 0.83% ksoftirqd/1 [kernel.kallsyms] [k] nf_iterate + 0.76% ksoftirqd/1 [kernel.kallsyms] [k] put_compound_page + 0.75% ksoftirqd/1 [kernel.kallsyms] [k] __rcu_read_lock Drop via ipset in RAW table with RCU-locking ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ With RCU locking, the RW-lock is gone. Drop performance in "raw" with ipset with RCU-locking: 11.3Mpps Performance-tested-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
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