From 72a3effaf633bcae9034b7e176bdbd78d64a71db Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 16 Nov 2006 02:30:37 -0800 Subject: [PATCH] [NET]: Size listen hash tables using backlog hint We currently allocate a fixed size (TCP_SYNQ_HSIZE=512) slots hash table for each LISTEN socket, regardless of various parameters (listen backlog for example) On x86_64, this means order-1 allocations (might fail), even for 'small' sockets, expecting few connections. On the contrary, a huge server wanting a backlog of 50000 is slowed down a bit because of this fixed limit. This patch makes the sizing of listen hash table a dynamic parameter, depending of : - net.core.somaxconn tunable (default is 128) - net.ipv4.tcp_max_syn_backlog tunable (default : 256, 1024 or 128) - backlog value given by user application (2nd parameter of listen()) For large allocations (bigger than PAGE_SIZE), we use vmalloc() instead of kmalloc(). We still limit memory allocation with the two existing tunables (somaxconn & tcp_max_syn_backlog). So for standard setups, this patch actually reduce RAM usage. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- include/net/request_sock.h | 8 ++++---- include/net/tcp.h | 1 - net/core/request_sock.c | 35 +++++++++++++++++++++++++---------- net/dccp/ipv4.c | 2 +- net/dccp/proto.c | 6 +++--- net/ipv4/af_inet.c | 2 +- net/ipv4/inet_connection_sock.c | 2 +- net/ipv4/tcp_ipv4.c | 6 +++--- net/ipv6/tcp_ipv6.c | 2 +- 9 files changed, 39 insertions(+), 25 deletions(-) diff --git a/include/net/request_sock.h b/include/net/request_sock.h index f743a94..b5b023e 100644 --- a/include/net/request_sock.h +++ b/include/net/request_sock.h @@ -28,8 +28,8 @@ struct proto; struct request_sock_ops { int family; - kmem_cache_t *slab; int obj_size; + kmem_cache_t *slab; int (*rtx_syn_ack)(struct sock *sk, struct request_sock *req, struct dst_entry *dst); @@ -51,13 +51,13 @@ struct request_sock { u32 rcv_wnd; /* rcv_wnd offered first time */ u32 ts_recent; unsigned long expires; - struct request_sock_ops *rsk_ops; + const struct request_sock_ops *rsk_ops; struct sock *sk; u32 secid; u32 peer_secid; }; -static inline struct request_sock *reqsk_alloc(struct request_sock_ops *ops) +static inline struct request_sock *reqsk_alloc(const struct request_sock_ops *ops) { struct request_sock *req = kmem_cache_alloc(ops->slab, SLAB_ATOMIC); @@ -121,7 +121,7 @@ struct request_sock_queue { }; extern int reqsk_queue_alloc(struct request_sock_queue *queue, - const int nr_table_entries); + unsigned int nr_table_entries); static inline struct listen_sock *reqsk_queue_yank_listen_sk(struct request_sock_queue *queue) { diff --git a/include/net/tcp.h b/include/net/tcp.h index 7a093d0..246916c 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -138,7 +138,6 @@ extern void tcp_time_wait(struct sock *sk, int state, int timeo); #define MAX_TCP_SYNCNT 127 #define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */ -#define TCP_SYNQ_HSIZE 512 /* Size of SYNACK hash table */ #define TCP_PAWS_24DAYS (60 * 60 * 24 * 24) #define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated diff --git a/net/core/request_sock.c b/net/core/request_sock.c index 79ebd75..5f0818d 100644 --- a/net/core/request_sock.c +++ b/net/core/request_sock.c @@ -15,6 +15,7 @@ #include #include #include +#include #include @@ -29,22 +30,31 @@ * it is absolutely not enough even at 100conn/sec. 256 cures most * of problems. This value is adjusted to 128 for very small machines * (<=32Mb of memory) and to 1024 on normal or better ones (>=256Mb). - * Further increasing requires to change hash table size. + * Note : Dont forget somaxconn that may limit backlog too. */ int sysctl_max_syn_backlog = 256; int reqsk_queue_alloc(struct request_sock_queue *queue, - const int nr_table_entries) + unsigned int nr_table_entries) { - const int lopt_size = sizeof(struct listen_sock) + - nr_table_entries * sizeof(struct request_sock *); - struct listen_sock *lopt = kzalloc(lopt_size, GFP_KERNEL); - + size_t lopt_size = sizeof(struct listen_sock); + struct listen_sock *lopt; + + nr_table_entries = min_t(u32, nr_table_entries, sysctl_max_syn_backlog); + nr_table_entries = max_t(u32, nr_table_entries, 8); + nr_table_entries = roundup_pow_of_two(nr_table_entries + 1); + lopt_size += nr_table_entries * sizeof(struct request_sock *); + if (lopt_size > PAGE_SIZE) + lopt = __vmalloc(lopt_size, + GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO, + PAGE_KERNEL); + else + lopt = kzalloc(lopt_size, GFP_KERNEL); if (lopt == NULL) return -ENOMEM; - for (lopt->max_qlen_log = 6; - (1 << lopt->max_qlen_log) < sysctl_max_syn_backlog; + for (lopt->max_qlen_log = 3; + (1 << lopt->max_qlen_log) < nr_table_entries; lopt->max_qlen_log++); get_random_bytes(&lopt->hash_rnd, sizeof(lopt->hash_rnd)); @@ -65,9 +75,11 @@ void reqsk_queue_destroy(struct request_sock_queue *queue) { /* make all the listen_opt local to us */ struct listen_sock *lopt = reqsk_queue_yank_listen_sk(queue); + size_t lopt_size = sizeof(struct listen_sock) + + lopt->nr_table_entries * sizeof(struct request_sock *); if (lopt->qlen != 0) { - int i; + unsigned int i; for (i = 0; i < lopt->nr_table_entries; i++) { struct request_sock *req; @@ -81,7 +93,10 @@ void reqsk_queue_destroy(struct request_sock_queue *queue) } BUG_TRAP(lopt->qlen == 0); - kfree(lopt); + if (lopt_size > PAGE_SIZE) + vfree(lopt); + else + kfree(lopt); } EXPORT_SYMBOL(reqsk_queue_destroy); diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c index e08e768..0a5d68d 100644 --- a/net/dccp/ipv4.c +++ b/net/dccp/ipv4.c @@ -1022,7 +1022,7 @@ static void dccp_v4_reqsk_destructor(struct request_sock *req) kfree(inet_rsk(req)->opt); } -static struct request_sock_ops dccp_request_sock_ops = { +static struct request_sock_ops dccp_request_sock_ops _read_mostly = { .family = PF_INET, .obj_size = sizeof(struct dccp_request_sock), .rtx_syn_ack = dccp_v4_send_response, diff --git a/net/dccp/proto.c b/net/dccp/proto.c index 72cbdcf..047d170 100644 --- a/net/dccp/proto.c +++ b/net/dccp/proto.c @@ -262,12 +262,12 @@ int dccp_destroy_sock(struct sock *sk) EXPORT_SYMBOL_GPL(dccp_destroy_sock); -static inline int dccp_listen_start(struct sock *sk) +static inline int dccp_listen_start(struct sock *sk, int backlog) { struct dccp_sock *dp = dccp_sk(sk); dp->dccps_role = DCCP_ROLE_LISTEN; - return inet_csk_listen_start(sk, TCP_SYNQ_HSIZE); + return inet_csk_listen_start(sk, backlog); } int dccp_disconnect(struct sock *sk, int flags) @@ -788,7 +788,7 @@ int inet_dccp_listen(struct socket *sock, int backlog) * FIXME: here it probably should be sk->sk_prot->listen_start * see tcp_listen_start */ - err = dccp_listen_start(sk); + err = dccp_listen_start(sk, backlog); if (err) goto out; } diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c index edcf093..4a81d54 100644 --- a/net/ipv4/af_inet.c +++ b/net/ipv4/af_inet.c @@ -204,7 +204,7 @@ int inet_listen(struct socket *sock, int backlog) * we can only allow the backlog to be adjusted. */ if (old_state != TCP_LISTEN) { - err = inet_csk_listen_start(sk, TCP_SYNQ_HSIZE); + err = inet_csk_listen_start(sk, backlog); if (err) goto out; } diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c index 96bbe2a..9d68837 100644 --- a/net/ipv4/inet_connection_sock.c +++ b/net/ipv4/inet_connection_sock.c @@ -343,7 +343,7 @@ struct dst_entry* inet_csk_route_req(struct sock *sk, EXPORT_SYMBOL_GPL(inet_csk_route_req); static inline u32 inet_synq_hash(const __be32 raddr, const __be16 rport, - const u32 rnd, const u16 synq_hsize) + const u32 rnd, const u32 synq_hsize) { return jhash_2words((__force u32)raddr, (__force u32)rport, rnd) & (synq_hsize - 1); } diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 22ef8bd..5fbf965 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -715,7 +715,7 @@ static struct ip_options *tcp_v4_save_options(struct sock *sk, return dopt; } -struct request_sock_ops tcp_request_sock_ops = { +struct request_sock_ops tcp_request_sock_ops __read_mostly = { .family = PF_INET, .obj_size = sizeof(struct tcp_request_sock), .rtx_syn_ack = tcp_v4_send_synack, @@ -1385,7 +1385,7 @@ static void *listening_get_next(struct seq_file *seq, void *cur) if (st->state == TCP_SEQ_STATE_OPENREQ) { struct request_sock *req = cur; - icsk = inet_csk(st->syn_wait_sk); + icsk = inet_csk(st->syn_wait_sk); req = req->dl_next; while (1) { while (req) { @@ -1395,7 +1395,7 @@ static void *listening_get_next(struct seq_file *seq, void *cur) } req = req->dl_next; } - if (++st->sbucket >= TCP_SYNQ_HSIZE) + if (++st->sbucket >= icsk->icsk_accept_queue.listen_opt->nr_table_entries) break; get_req: req = icsk->icsk_accept_queue.listen_opt->syn_table[st->sbucket]; diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index eb6d145..1a3c46c 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -526,7 +526,7 @@ static void tcp_v6_reqsk_destructor(struct request_sock *req) kfree_skb(inet6_rsk(req)->pktopts); } -static struct request_sock_ops tcp6_request_sock_ops = { +static struct request_sock_ops tcp6_request_sock_ops _read_mostly = { .family = AF_INET6, .obj_size = sizeof(struct tcp6_request_sock), .rtx_syn_ack = tcp_v6_send_synack, -- 2.7.4