diff options
| author | Eric Dumazet <edumazet@google.com> | 2019-06-14 16:22:19 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2019-06-14 20:18:28 -0700 |
| commit | ede61ca474a0348b975d9824565b66c7595461de (patch) | |
| tree | bc0770bb86ede5aed3f91f68773e412ee1067d07 | |
| parent | a8e11e5c5611a9f70470aebeb2c1dd6132f609d7 (diff) | |
tcp: add tcp_rx_skb_cache sysctl
Instead of relying on rps_needed, it is safer to use a separate
static key, since we do not want to enable TCP rx_skb_cache
by default. This feature can cause huge increase of memory
usage on hosts with millions of sockets.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | Documentation/networking/ip-sysctl.txt | 8 | ||||
| -rw-r--r-- | include/net/sock.h | 6 | ||||
| -rw-r--r-- | net/ipv4/sysctl_net_ipv4.c | 9 |
3 files changed, 19 insertions, 4 deletions
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index 14fe93049d28..288aa264ac26 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -772,6 +772,14 @@ tcp_challenge_ack_limit - INTEGER in RFC 5961 (Improving TCP's Robustness to Blind In-Window Attacks) Default: 100 +tcp_rx_skb_cache - BOOLEAN + Controls a per TCP socket cache of one skb, that might help + performance of some workloads. This might be dangerous + on systems with a lot of TCP sockets, since it increases + memory usage. + + Default: 0 (disabled) + UDP variables: udp_l3mdev_accept - BOOLEAN diff --git a/include/net/sock.h b/include/net/sock.h index e9d769c04637..b02645e2dfad 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -2433,13 +2433,11 @@ static inline void skb_setup_tx_timestamp(struct sk_buff *skb, __u16 tsflags) * This routine must be called with interrupts disabled or with the socket * locked so that the sk_buff queue operation is ok. */ +DECLARE_STATIC_KEY_FALSE(tcp_rx_skb_cache_key); static inline void sk_eat_skb(struct sock *sk, struct sk_buff *skb) { __skb_unlink(skb, &sk->sk_receive_queue); - if ( -#ifdef CONFIG_RPS - !static_branch_unlikely(&rps_needed) && -#endif + if (static_branch_unlikely(&tcp_rx_skb_cache_key) && !sk->sk_rx_skb_cache) { sk->sk_rx_skb_cache = skb; skb_orphan(skb); diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c index 875867b64d6a..886b58d31351 100644 --- a/net/ipv4/sysctl_net_ipv4.c +++ b/net/ipv4/sysctl_net_ipv4.c @@ -51,6 +51,9 @@ static int comp_sack_nr_max = 255; static u32 u32_max_div_HZ = UINT_MAX / HZ; static int one_day_secs = 24 * 3600; +DEFINE_STATIC_KEY_FALSE(tcp_rx_skb_cache_key); +EXPORT_SYMBOL(tcp_rx_skb_cache_key); + /* obsolete */ static int sysctl_tcp_low_latency __read_mostly; @@ -559,6 +562,12 @@ static struct ctl_table ipv4_table[] = { .extra1 = &sysctl_fib_sync_mem_min, .extra2 = &sysctl_fib_sync_mem_max, }, + { + .procname = "tcp_rx_skb_cache", + .data = &tcp_rx_skb_cache_key.key, + .mode = 0644, + .proc_handler = proc_do_static_key, + }, { } }; |