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authorThomas Graf <tgraf@suug.ch>2014-08-02 11:47:45 +0200
committerDavid S. Miller <davem@davemloft.net>2014-08-02 19:49:38 -0700
commite341694e3eb57fcda9f1adc7bfea42fe080d8d7a (patch)
tree12ac538a44609b3075bfaf98999ba68d9ff575cc /net/netlink/af_netlink.h
parent7e1e77636e36075ebf118298855268468f1028e8 (diff)
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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 <tgraf@suug.ch> Reviewed-by: Nikolay Aleksandrov <nikolay@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/netlink/af_netlink.h')
-rw-r--r--net/netlink/af_netlink.h18
1 files changed, 4 insertions, 14 deletions
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 <linux/rhashtable.h>
#include <net/sock.h>
#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;