diff options
| author | Eric Dumazet <edumazet@google.com> | 2018-03-31 23:16:26 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-04-01 21:08:21 +0300 |
| commit | 1f4c6eb24029689a40dceae561e31ff6926d7f0d (patch) | |
| tree | 253468761ee8e0f7a7cd97f21c24ef3c841529e7 /net | |
| parent | 694aba690de062cf27b28a5e56e7a5a7185b0a1c (diff) | |
| download | linux-1f4c6eb24029689a40dceae561e31ff6926d7f0d.tar.xz | |
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 <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv6/ip6_output.c | 17 |
1 files changed, 12 insertions, 5 deletions
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; } |