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| author | Pavel Begunkov <asml.silence@gmail.com> | 2022-07-12 21:52:26 +0100 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2022-07-18 19:58:29 -0700 |
| commit | 773ba4fe9104a64a54d1c00f0fb6ffb95def2b03 (patch) | |
| tree | 5eda2b3a67d5dee6e800103090fcebdd3975bd67 /net/ipv6/ip6_output.c | |
| parent | 8eb77cc73977d88787b37c92831b1c242e035396 (diff) | |
| download | lwn-773ba4fe9104a64a54d1c00f0fb6ffb95def2b03.tar.gz lwn-773ba4fe9104a64a54d1c00f0fb6ffb95def2b03.zip | |
ipv6: avoid partial copy for zc
Even when zerocopy transmission is requested and possible,
__ip_append_data() will still copy a small chunk of data just because it
allocated some extra linear space (e.g. 128 bytes). It wastes CPU cycles
on copy and iter manipulations and also misalignes potentially aligned
data. Avoid such copies. And as a bonus we can allocate smaller skb.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/ipv6/ip6_output.c')
| -rw-r--r-- | net/ipv6/ip6_output.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index 77e3f5970ce4..fc74ce3ed8cc 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -1464,6 +1464,7 @@ static int __ip6_append_data(struct sock *sk, int copy; int err; int offset = 0; + bool zc = false; u32 tskey = 0; struct rt6_info *rt = (struct rt6_info *)cork->dst; struct ipv6_txoptions *opt = v6_cork->opt; @@ -1549,6 +1550,7 @@ emsgsize: if (rt->dst.dev->features & NETIF_F_SG && csummode == CHECKSUM_PARTIAL) { paged = true; + zc = true; } else { uarg->zerocopy = 0; skb_zcopy_set(skb, uarg, &extra_uref); @@ -1630,9 +1632,12 @@ alloc_new_skb: (fraglen + alloc_extra < SKB_MAX_ALLOC || !(rt->dst.dev->features & NETIF_F_SG))) alloclen = fraglen; - else { + else if (!zc) { alloclen = min_t(int, fraglen, MAX_HEADER); pagedlen = fraglen - alloclen; + } else { + alloclen = fragheaderlen + transhdrlen; + pagedlen = datalen - transhdrlen; } alloclen += alloc_extra; |