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authorEric Dumazet <edumazet@google.com>2020-03-24 19:23:21 -0700
committerDavid S. Miller <davem@davemloft.net>2020-03-25 11:30:40 -0700
commit29f3490ba9d2399d3d1b20c4aa74592d92bd4e11 (patch)
tree54aab071a4a33ef17587a53e3e9409ae249d6629
parentcxgb4: remove set but not used variable 'tab' (diff)
downloadwireguard-linux-29f3490ba9d2399d3d1b20c4aa74592d92bd4e11.tar.xz
wireguard-linux-29f3490ba9d2399d3d1b20c4aa74592d92bd4e11.zip
net: use indirect call wrappers for skb_copy_datagram_iter()davem/net-next
TCP recvmsg() calls skb_copy_datagram_iter(), which calls an indirect function (cb pointing to simple_copy_to_iter()) for every MSS (fragment) present in the skb. CONFIG_RETPOLINE=y forces a very expensive operation that we can avoid thanks to indirect call wrappers. This patch gives a 13% increase of performance on a single flow, if the bottleneck is the thread reading the TCP socket. Fixes: 950fcaecd5cc ("datagram: consolidate datagram copy to iter helpers") Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Paolo Abeni <pabeni@redhat.com> Acked-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/core/datagram.c14
1 files changed, 11 insertions, 3 deletions
diff --git a/net/core/datagram.c b/net/core/datagram.c
index 4213081c6ed3..639745d4f3b9 100644
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -51,6 +51,7 @@
#include <linux/slab.h>
#include <linux/pagemap.h>
#include <linux/uio.h>
+#include <linux/indirect_call_wrapper.h>
#include <net/protocol.h>
#include <linux/skbuff.h>
@@ -403,6 +404,11 @@ int skb_kill_datagram(struct sock *sk, struct sk_buff *skb, unsigned int flags)
}
EXPORT_SYMBOL(skb_kill_datagram);
+INDIRECT_CALLABLE_DECLARE(static size_t simple_copy_to_iter(const void *addr,
+ size_t bytes,
+ void *data __always_unused,
+ struct iov_iter *i));
+
static int __skb_datagram_iter(const struct sk_buff *skb, int offset,
struct iov_iter *to, int len, bool fault_short,
size_t (*cb)(const void *, size_t, void *,
@@ -416,7 +422,8 @@ static int __skb_datagram_iter(const struct sk_buff *skb, int offset,
if (copy > 0) {
if (copy > len)
copy = len;
- n = cb(skb->data + offset, copy, data, to);
+ n = INDIRECT_CALL_1(cb, simple_copy_to_iter,
+ skb->data + offset, copy, data, to);
offset += n;
if (n != copy)
goto short_copy;
@@ -438,8 +445,9 @@ static int __skb_datagram_iter(const struct sk_buff *skb, int offset,
if (copy > len)
copy = len;
- n = cb(vaddr + skb_frag_off(frag) + offset - start,
- copy, data, to);
+ n = INDIRECT_CALL_1(cb, simple_copy_to_iter,
+ vaddr + skb_frag_off(frag) + offset - start,
+ copy, data, to);
kunmap(page);
offset += n;
if (n != copy)