From 1f4c6eb24029689a40dceae561e31ff6926d7f0d Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sat, 31 Mar 2018 13:16:26 -0700 Subject: ipv6: factorize sk_wmem_alloc updates done by __ip6_append_data() While testing my inet defrag changes, I found that the senders could spend ~20% of cpu cycles in skb_set_owner_w() updating sk->sk_wmem_alloc for every fragment they cook, competing with TX completion of prior skbs possibly happening on another cpus. The solution to this problem is to use alloc_skb() instead of sock_wmalloc() and manually perform a single sk_wmem_alloc change. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv6/ip6_output.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) (limited to 'net') diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index 2c7f09c3c39e..323d7a354ffb 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -1259,6 +1259,7 @@ static int __ip6_append_data(struct sock *sk, struct ipv6_txoptions *opt = v6_cork->opt; int csummode = CHECKSUM_NONE; unsigned int maxnonfragsize, headersize; + unsigned int wmem_alloc_delta = 0; skb = skb_peek_tail(queue); if (!skb) { @@ -1411,11 +1412,10 @@ alloc_new_skb: (flags & MSG_DONTWAIT), &err); } else { skb = NULL; - if (refcount_read(&sk->sk_wmem_alloc) <= + if (refcount_read(&sk->sk_wmem_alloc) + wmem_alloc_delta <= 2 * sk->sk_sndbuf) - skb = sock_wmalloc(sk, - alloclen + hh_len, 1, - sk->sk_allocation); + skb = alloc_skb(alloclen + hh_len, + sk->sk_allocation); if (unlikely(!skb)) err = -ENOBUFS; } @@ -1474,6 +1474,11 @@ alloc_new_skb: /* * Put the packet on the pending queue */ + if (!skb->destructor) { + skb->destructor = sock_wfree; + skb->sk = sk; + wmem_alloc_delta += skb->truesize; + } __skb_queue_tail(queue, skb); continue; } @@ -1520,12 +1525,13 @@ alloc_new_skb: skb->len += copy; skb->data_len += copy; skb->truesize += copy; - refcount_add(copy, &sk->sk_wmem_alloc); + wmem_alloc_delta += copy; } offset += copy; length -= copy; } + refcount_add(wmem_alloc_delta, &sk->sk_wmem_alloc); return 0; error_efault: @@ -1533,6 +1539,7 @@ error_efault: error: cork->length -= length; IP6_INC_STATS(sock_net(sk), rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS); + refcount_add(wmem_alloc_delta, &sk->sk_wmem_alloc); return err; } -- cgit v1.2.3-58-ga151