diff options
| author |   Eric Dumazet <edumazet@google.com> | 2020-03-24 19:23:21 -0700 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2020-03-25 11:30:40 -0700 |
| commit | 29f3490ba9d2399d3d1b20c4aa74592d92bd4e11 (patch) | |
| tree | 54aab071a4a33ef17587a53e3e9409ae249d6629 /net/core/datagram.c | |
| parent | cxgb4: remove set but not used variable 'tab' (diff) | |
| download | linux-dev-29f3490ba9d2399d3d1b20c4aa74592d92bd4e11.tar.xz linux-dev-29f3490ba9d2399d3d1b20c4aa74592d92bd4e11.zip | |
net: use indirect call wrappers for skb_copy_datagram_iter()
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>
Diffstat (limited to 'net/core/datagram.c')
| -rw-r--r-- | net/core/datagram.c | 14 |
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) |