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net: sk_free_datagram() should use sk_mem_reclaim_partial()

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I noticed a contention on udp_memory_allocated on regular UDP applications.

While tcp_memory_allocated is seldom used, it appears each incoming UDP frame
is currently touching udp_memory_allocated when queued, and when received by
application.

One possible solution is to use sk_mem_reclaim_partial() instead of
sk_mem_reclaim(), so that we keep a small reserve (less than one page)
of memory for each UDP socket.

We did something very similar on TCP side in commit
9993e7d313
([TCP]: Do not purge sk_forward_alloc entirely in tcp_delack_timer())

A more complex solution would need to convert prot->memory_allocated to
use a percpu_counter with batches of 64 or 128 pages.

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2008-11-05 01:38:06 -08:00 committed by David S. Miller
parent d99a7bd210
commit 270acefafe
1 changed files with 2 additions and 3 deletions
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5
net/core/datagram.c
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@ -209,7 +209,7 @@ struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned flags,
void skb_free_datagram(struct sock *sk, struct sk_buff *skb)
{
kfree_skb(skb);
sk_mem_reclaim(sk);
sk_mem_reclaim_partial(sk);
}
/**
@ -248,8 +248,7 @@ int skb_kill_datagram(struct sock *sk, struct sk_buff *skb, unsigned int flags)
spin_unlock_bh(&sk->sk_receive_queue.lock);
}
kfree_skb(skb);
sk_mem_reclaim(sk);
skb_free_datagram(sk, skb);
return err;
}