From e341694e3eb57fcda9f1adc7bfea42fe080d8d7a Mon Sep 17 00:00:00 2001 From: Thomas Graf Date: Sat, 2 Aug 2014 11:47:45 +0200 Subject: netlink: Convert netlink_lookup() to use RCU protected hash table Heavy Netlink users such as Open vSwitch spend a considerable amount of time in netlink_lookup() due to the read-lock on nl_table_lock. Use of RCU relieves the lock contention. Makes use of the new resizable hash table to avoid locking on the lookup. The hash table will grow if entries exceeds 75% of table size up to a total table size of 64K. It will automatically shrink if usage falls below 30%. Also splits nl_table_lock into a separate mutex to protect hash table mutations and allow synchronize_rcu() to sleep while waiting for readers during expansion and shrinking. Before: 9.16% kpktgend_0 [openvswitch] [k] masked_flow_lookup 6.42% kpktgend_0 [pktgen] [k] mod_cur_headers 6.26% kpktgend_0 [pktgen] [k] pktgen_thread_worker 6.23% kpktgend_0 [kernel.kallsyms] [k] memset 4.79% kpktgend_0 [kernel.kallsyms] [k] netlink_lookup 4.37% kpktgend_0 [kernel.kallsyms] [k] memcpy 3.60% kpktgend_0 [openvswitch] [k] ovs_flow_extract 2.69% kpktgend_0 [kernel.kallsyms] [k] jhash2 After: 15.26% kpktgend_0 [openvswitch] [k] masked_flow_lookup 8.12% kpktgend_0 [pktgen] [k] pktgen_thread_worker 7.92% kpktgend_0 [pktgen] [k] mod_cur_headers 5.11% kpktgend_0 [kernel.kallsyms] [k] memset 4.11% kpktgend_0 [openvswitch] [k] ovs_flow_extract 4.06% kpktgend_0 [kernel.kallsyms] [k] _raw_spin_lock 3.90% kpktgend_0 [kernel.kallsyms] [k] jhash2 [...] 0.67% kpktgend_0 [kernel.kallsyms] [k] netlink_lookup Signed-off-by: Thomas Graf Reviewed-by: Nikolay Aleksandrov Signed-off-by: David S. Miller --- net/netlink/af_netlink.h | 18 ++++-------------- 1 file changed, 4 insertions(+), 14 deletions(-) (limited to 'net/netlink/af_netlink.h') diff --git a/net/netlink/af_netlink.h b/net/netlink/af_netlink.h index 0b59d441f5b6..60f631fb7087 100644 --- a/net/netlink/af_netlink.h +++ b/net/netlink/af_netlink.h @@ -1,6 +1,7 @@ #ifndef _AF_NETLINK_H #define _AF_NETLINK_H +#include #include #define NLGRPSZ(x) (ALIGN(x, sizeof(unsigned long) * 8) / 8) @@ -47,6 +48,8 @@ struct netlink_sock { struct netlink_ring tx_ring; atomic_t mapped; #endif /* CONFIG_NETLINK_MMAP */ + + struct rhash_head node; }; static inline struct netlink_sock *nlk_sk(struct sock *sk) @@ -54,21 +57,8 @@ static inline struct netlink_sock *nlk_sk(struct sock *sk) return container_of(sk, struct netlink_sock, sk); } -struct nl_portid_hash { - struct hlist_head *table; - unsigned long rehash_time; - - unsigned int mask; - unsigned int shift; - - unsigned int entries; - unsigned int max_shift; - - u32 rnd; -}; - struct netlink_table { - struct nl_portid_hash hash; + struct rhashtable hash; struct hlist_head mc_list; struct listeners __rcu *listeners; unsigned int flags; -- cgit v1.2.3