diff options
| author | Eric Dumazet <edumazet@google.com> | 2020-09-30 14:54:57 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-09-30 23:21:30 +0200 |
| commit | a37c2134bed6f28c6d6aefa2699331e6e4e9c4f1 (patch) | |
| tree | f1ce9d23e66fd51f5efcd7ea38663db68f27d5ca /include | |
| parent | inet: remove icsk_ack.blocked (diff) | |
| download | linux-a37c2134bed6f28c6d6aefa2699331e6e4e9c4f1.tar.xz linux-a37c2134bed6f28c6d6aefa2699331e6e4e9c4f1.zip | |
tcp: add exponential backoff in __tcp_send_ack()
Whenever host is under very high memory pressure,
__tcp_send_ack() skb allocation fails, and we setup
a 200 ms (TCP_DELACK_MAX) timer before retrying.
On hosts with high number of TCP sockets, we can spend
considerable amount of cpu cycles in these attempts,
add high pressure on various spinlocks in mm-layer,
ultimately blocking threads attempting to free space
from making any progress.
This patch adds standard exponential backoff to avoid
adding fuel to the fire.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include')
| -rw-r--r-- | include/net/inet_connection_sock.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h index 79875f976190..7338b3865a2a 100644 --- a/include/net/inet_connection_sock.h +++ b/include/net/inet_connection_sock.h @@ -110,7 +110,7 @@ struct inet_connection_sock { __u8 pending; /* ACK is pending */ __u8 quick; /* Scheduled number of quick acks */ __u8 pingpong; /* The session is interactive */ - /* one byte hole. */ + __u8 retry; /* Number of attempts */ __u32 ato; /* Predicted tick of soft clock */ unsigned long timeout; /* Currently scheduled timeout */ __u32 lrcvtime; /* timestamp of last received data packet */ @@ -199,6 +199,7 @@ static inline void inet_csk_clear_xmit_timer(struct sock *sk, const int what) #endif } else if (what == ICSK_TIME_DACK) { icsk->icsk_ack.pending = 0; + icsk->icsk_ack.retry = 0; #ifdef INET_CSK_CLEAR_TIMERS sk_stop_timer(sk, &icsk->icsk_delack_timer); #endif |