Re: [PATCH v2 net-next 00/11] net: various udp/tcp changes

[David Miller]

From: Eric Dumazet 
Date: Fri,  1 Apr 2016 08:52:11 -0700

> First round of patches for linux-4.7

Nice series, applied.

I honestly think we can elide socket memory accounting for
(non-data-bearing) SYNACKs if that's showing up in the perf
profiles for SYN attacks.

[PATCH v2 net-next 00/11] net: various udp/tcp changes

[Eric Dumazet]

First round of patches for linux-4.7

Add a generic facility for sockets to be freed after an RCU grace
period, if they need to.

Then UDP stack is changed to no longer use SLAB_DESTROY_BY_RCU,
in order to speedup rx processing for traffic encapsulated in UDP.
It gives a 17 % speedup for normal UDP reception in stress conditions.

Then TCP listeners are changed to use SOCK_RCU_FREE as well
to avoid touching sk_refcnt in synflood case :
I got up to 30 % performance increase for a mono listener.

Then three patches add SK_MEMINFO_DROPS to sock_diag
and add per socket rx drops accounting to TCP.

Last patch adds rate limiting on ACK sent on behalf of SYN_RECV
to better resist to SYNFLOOD targeting one or few flows.


Eric Dumazet (11):
  net: add SOCK_RCU_FREE socket flag
  udp: no longer use SLAB_DESTROY_BY_RCU
  tcp/dccp: remove BH disable/enable in lookup
  tcp/dccp: use rcu locking in inet_diag_find_one_icsk()
  inet: reqsk_alloc() needs to take care of dead listeners
  tcp/dccp: do not touch listener sk_refcnt under synflood
  sock_diag: add SK_MEMINFO_DROPS
  tcp: increment sk_drops for dropped rx packets
  tcp: increment sk_drops for listeners
  ipv4: tcp: set SOCK_USE_WRITE_QUEUE for ip_send_unicast_reply()
  tcp: rate limit ACK sent by SYN_RECV request sockets

 include/linux/udp.h|   8 +-
 include/net/inet6_hashtables.h |  12 +-
 include/net/inet_hashtables.h  |  47 +++
 include/net/request_sock.h |  31 +++--
 include/net/sock.h |  21 ++-
 include/net/tcp.h  |  13 ++
 include/net/udp.h  |   2 +-
 include/uapi/linux/sock_diag.h |   1 +
 net/core/sock.c|  15 ++-
 net/core/sock_diag.c   |   1 +
 net/dccp/ipv4.c|   7 +-
 net/dccp/ipv6.c|   7 +-
 net/ipv4/inet_diag.c   |  10 +-
 net/ipv4/inet_hashtables.c |  77 ---
 net/ipv4/tcp_input.c   |  41 +++---
 net/ipv4/tcp_ipv4.c|  74 ++-
 net/ipv4/tcp_minisocks.c   |   5 +-
 net/ipv4/udp.c | 293 -
 net/ipv4/udp_diag.c|  18 +--
 net/ipv6/inet6_hashtables.c|  62 +++--
 net/ipv6/tcp_ipv6.c|  32 +++--
 net/ipv6/udp.c | 196 +--
 net/netfilter/xt_socket.c  |   6 +-
 23 files changed, 401 insertions(+), 578 deletions(-)

-- 
2.8.0.rc3.226.g39d4020