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linux/include/net/inet_timewait_sock.h
Eric Dumazet 3ab5aee7fe net: Convert TCP & DCCP hash tables to use RCU / hlist_nulls 
RCU was added to UDP lookups, using a fast infrastructure :
- sockets kmem_cache use SLAB_DESTROY_BY_RCU and dont pay the
  price of call_rcu() at freeing time.
- hlist_nulls permits to use few memory barriers.

This patch uses same infrastructure for TCP/DCCP established
and timewait sockets.

Thanks to SLAB_DESTROY_BY_RCU, no slowdown for applications
using short lived TCP connections. A followup patch, converting
rwlocks to spinlocks will even speedup this case.

__inet_lookup_established() is pretty fast now we dont have to
dirty a contended cache line (read_lock/read_unlock)

Only established and timewait hashtable are converted to RCU
(bind table and listen table are still using traditional locking)

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-16 19:40:17 -08:00

233 lines
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/*
* INET An implementation of the TCP/IP protocol suite for the LINUX
* operating system. INET is implemented using the BSD Socket
* interface as the means of communication with the user level.
*
* Definitions for a generic INET TIMEWAIT sock
*
* From code originally in net/tcp.h
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#ifndef _INET_TIMEWAIT_SOCK_
#define _INET_TIMEWAIT_SOCK_
#include <linux/list.h>
#include <linux/module.h>
#include <linux/timer.h>
#include <linux/types.h>
#include <linux/workqueue.h>
#include <net/inet_sock.h>
#include <net/sock.h>
#include <net/tcp_states.h>
#include <net/timewait_sock.h>
#include <asm/atomic.h>
struct inet_hashinfo;
#define INET_TWDR_RECYCLE_SLOTS_LOG 5
#define INET_TWDR_RECYCLE_SLOTS (1 << INET_TWDR_RECYCLE_SLOTS_LOG)
/*
* If time > 4sec, it is "slow" path, no recycling is required,
* so that we select tick to get range about 4 seconds.
*/
#if HZ <= 16 || HZ > 4096
# error Unsupported: HZ <= 16 or HZ > 4096
#elif HZ <= 32
# define INET_TWDR_RECYCLE_TICK (5 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
#elif HZ <= 64
# define INET_TWDR_RECYCLE_TICK (6 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
#elif HZ <= 128
# define INET_TWDR_RECYCLE_TICK (7 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
#elif HZ <= 256
# define INET_TWDR_RECYCLE_TICK (8 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
#elif HZ <= 512
# define INET_TWDR_RECYCLE_TICK (9 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
#elif HZ <= 1024
# define INET_TWDR_RECYCLE_TICK (10 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
#elif HZ <= 2048
# define INET_TWDR_RECYCLE_TICK (11 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
#else
# define INET_TWDR_RECYCLE_TICK (12 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
#endif
/* TIME_WAIT reaping mechanism. */
#define INET_TWDR_TWKILL_SLOTS 8 /* Please keep this a power of 2. */
#define INET_TWDR_TWKILL_QUOTA 100
struct inet_timewait_death_row {
/* Short-time timewait calendar */
int twcal_hand;
unsigned long twcal_jiffie;
struct timer_list twcal_timer;
struct hlist_head twcal_row[INET_TWDR_RECYCLE_SLOTS];
spinlock_t death_lock;
int tw_count;
int period;
u32 thread_slots;
struct work_struct twkill_work;
struct timer_list tw_timer;
int slot;
struct hlist_head cells[INET_TWDR_TWKILL_SLOTS];
struct inet_hashinfo *hashinfo;
int sysctl_tw_recycle;
int sysctl_max_tw_buckets;
};
extern void inet_twdr_hangman(unsigned long data);
extern void inet_twdr_twkill_work(struct work_struct *work);
extern void inet_twdr_twcal_tick(unsigned long data);
#if (BITS_PER_LONG == 64)
#define INET_TIMEWAIT_ADDRCMP_ALIGN_BYTES 8
#else
#define INET_TIMEWAIT_ADDRCMP_ALIGN_BYTES 4
#endif
struct inet_bind_bucket;
/*
* This is a TIME_WAIT sock. It works around the memory consumption
* problems of sockets in such a state on heavily loaded servers, but
* without violating the protocol specification.
*/
struct inet_timewait_sock {
/*
* Now struct sock also uses sock_common, so please just
* don't add nothing before this first member (__tw_common) --acme
*/
struct sock_common __tw_common;
#define tw_family __tw_common.skc_family
#define tw_state __tw_common.skc_state
#define tw_reuse __tw_common.skc_reuse
#define tw_bound_dev_if __tw_common.skc_bound_dev_if
#define tw_node __tw_common.skc_nulls_node
#define tw_bind_node __tw_common.skc_bind_node
#define tw_refcnt __tw_common.skc_refcnt
#define tw_hash __tw_common.skc_hash
#define tw_prot __tw_common.skc_prot
#define tw_net __tw_common.skc_net
int tw_timeout;
volatile unsigned char tw_substate;
/* 3 bits hole, try to pack */
unsigned char tw_rcv_wscale;
/* Socket demultiplex comparisons on incoming packets. */
/* these five are in inet_sock */
__be16 tw_sport;
__be32 tw_daddr __attribute__((aligned(INET_TIMEWAIT_ADDRCMP_ALIGN_BYTES)));
__be32 tw_rcv_saddr;
__be16 tw_dport;
__u16 tw_num;
/* And these are ours. */
__u8 tw_ipv6only:1,
tw_transparent:1;
/* 15 bits hole, try to pack */
__u16 tw_ipv6_offset;
unsigned long tw_ttd;
struct inet_bind_bucket *tw_tb;
struct hlist_node tw_death_node;
};
static inline void inet_twsk_add_node_rcu(struct inet_timewait_sock *tw,
struct hlist_nulls_head *list)
{
hlist_nulls_add_head_rcu(&tw->tw_node, list);
}
static inline void inet_twsk_add_bind_node(struct inet_timewait_sock *tw,
struct hlist_head *list)
{
hlist_add_head(&tw->tw_bind_node, list);
}
static inline int inet_twsk_dead_hashed(const struct inet_timewait_sock *tw)
{
return !hlist_unhashed(&tw->tw_death_node);
}
static inline void inet_twsk_dead_node_init(struct inet_timewait_sock *tw)
{
tw->tw_death_node.pprev = NULL;
}
static inline void __inet_twsk_del_dead_node(struct inet_timewait_sock *tw)
{
__hlist_del(&tw->tw_death_node);
inet_twsk_dead_node_init(tw);
}
static inline int inet_twsk_del_dead_node(struct inet_timewait_sock *tw)
{
if (inet_twsk_dead_hashed(tw)) {
__inet_twsk_del_dead_node(tw);
return 1;
}
return 0;
}
#define inet_twsk_for_each(tw, node, head) \
hlist_nulls_for_each_entry(tw, node, head, tw_node)
#define inet_twsk_for_each_inmate(tw, node, jail) \
hlist_for_each_entry(tw, node, jail, tw_death_node)
#define inet_twsk_for_each_inmate_safe(tw, node, safe, jail) \
hlist_for_each_entry_safe(tw, node, safe, jail, tw_death_node)
static inline struct inet_timewait_sock *inet_twsk(const struct sock *sk)
{
return (struct inet_timewait_sock *)sk;
}
static inline __be32 inet_rcv_saddr(const struct sock *sk)
{
return likely(sk->sk_state != TCP_TIME_WAIT) ?
inet_sk(sk)->rcv_saddr : inet_twsk(sk)->tw_rcv_saddr;
}
extern void inet_twsk_put(struct inet_timewait_sock *tw);
extern struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk,
const int state);
extern void __inet_twsk_hashdance(struct inet_timewait_sock *tw,
struct sock *sk,
struct inet_hashinfo *hashinfo);
extern void inet_twsk_schedule(struct inet_timewait_sock *tw,
struct inet_timewait_death_row *twdr,
const int timeo, const int timewait_len);
extern void inet_twsk_deschedule(struct inet_timewait_sock *tw,
struct inet_timewait_death_row *twdr);
extern void inet_twsk_purge(struct net *net, struct inet_hashinfo *hashinfo,
struct inet_timewait_death_row *twdr, int family);
static inline
struct net *twsk_net(const struct inet_timewait_sock *twsk)
{
#ifdef CONFIG_NET_NS
return twsk->tw_net;
#else
return &init_net;
#endif
}
static inline
void twsk_net_set(struct inet_timewait_sock *twsk, struct net *net)
{
#ifdef CONFIG_NET_NS
twsk->tw_net = net;
#endif
}
#endif /* _INET_TIMEWAIT_SOCK_ */
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