net: sk_add_backlog() take rmem_alloc into account

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Current socket backlog limit is not enough to really stop DDOS attacks,
because user thread spend many time to process a full backlog each
round, and user might crazy spin on socket lock.

We should add backlog size and receive_queue size (aka rmem_alloc) to
pace writers, and let user run without being slow down too much.

Introduce a sk_rcvqueues_full() helper, to avoid taking socket lock in
stress situations.

Under huge stress from a multiqueue/RPS enabled NIC, a single flow udp
receiver can now process ~200.000 pps (instead of ~100 pps before the
patch) on a 8 core machine.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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This commit is contained in:

Eric Dumazet 2010-04-27 15:13:20 -07:00 • committed by David S. Miller

parent 6e7676c1a7

commit c377411f24

5 changed files with 27 additions and 6 deletions

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13

include/net/sock.h

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5

net/core/sock.c

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4

net/ipv4/udp.c

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8

net/ipv6/udp.c

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3

net/sctp/socket.c

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