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[v5,net-next,0/3] udp: Add 4-tuple hash for connected sockets

Message ID 20241018114535.35712-1-lulie@linux.alibaba.com (mailing list archive)
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Series udp: Add 4-tuple hash for connected sockets | expand

Message

Philo Lu Oct. 18, 2024, 11:45 a.m. UTC 
This patchset introduces 4-tuple hash for connected udp sockets, to make
connected udp lookup faster. Test using udpgso_bench_tx/rx shows no
obvious difference w/ and w/o this patchset for unconnected socket
receiving (see v4 thread).

Patch1: Add a new counter for hslot2 named hash4_cnt, to avoid cache line
        miss when lookup.
Patch2 and 3: Implement 4-tuple hash for ipv4.
(That for ipv6 is in progress.)

The detailed motivation is described in Patch 3.

The 4-tuple hash increases the size of udp_sock and udp_hslot. Thus add it
with CONFIG_BASE_SMALL check, i.e., it's a no op with CONFIG_BASE_SMALL.

AFAICS the patchset can be further improved by:
(a) Better interact with hash2/reuseport. Now hash4 hardly affects other
mechanisms, but maintaining sockets in both hash4 and hash2 lists seems
unnecessary.
(b) Support early demux and ipv6.

changelogs:
v4 -> v5 (Paolo Abeni):
- Add CONFIG_BASE_SMALL with which udp hash4 does nothing

v3 -> v4 (Willem de Bruijn):
- fix mistakes in udp_pernet_table_alloc()

RFCv2 -> v3 (Gur Stavi):
- minor fix in udp_hashslot2() and udp_table_init()
- add rcu sync in rehash4()

RFCv1 -> RFCv2:
- add a new struct for hslot2
- remove the sockopt UDP_HASH4 because it has little side effect for
  unconnected sockets
- add rehash in connect()
- re-organize the patch into 3 smaller ones
- other minor fix

v4:
https://lore.kernel.org/all/20241012012918.70888-1-lulie@linux.alibaba.com/
v3:
https://lore.kernel.org/all/20241010090351.79698-1-lulie@linux.alibaba.com/
RFCv2:
https://lore.kernel.org/all/20240924110414.52618-1-lulie@linux.alibaba.com/
RFCv1:
https://lore.kernel.org/all/20240913100941.8565-1-lulie@linux.alibaba.com/

Philo Lu (3):
  net/udp: Add a new struct for hash2 slot
  net/udp: Add 4-tuple hash list basis
  ipv4/udp: Add 4-tuple hash for connected socket

 include/linux/udp.h |  11 +++
 include/net/udp.h   | 111 +++++++++++++++++++++-
 net/ipv4/udp.c      | 217 +++++++++++++++++++++++++++++++++++++++-----
 net/ipv6/udp.c      |  17 ++--
 4 files changed, 317 insertions(+), 39 deletions(-)

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2.32.0.3.g01195cf9f