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bpf: Remove extra lock_sock for TCP_ZEROCOPY_RECEIVE

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[ Upstream commit 9cacf81f8161111db25f98e78a7a0e32ae142b3f ]

Add custom implementation of getsockopt hook for TCP_ZEROCOPY_RECEIVE.
We skip generic hooks for TCP_ZEROCOPY_RECEIVE and have a custom
call in do_tcp_getsockopt using the on-stack data. This removes
3% overhead for locking/unlocking the socket.

Without this patch:
     3.38%     0.07%  tcp_mmap  [kernel.kallsyms]  [k] __cgroup_bpf_run_filter_getsockopt
            |
             --3.30%--__cgroup_bpf_run_filter_getsockopt
                       |
                        --0.81%--__kmalloc

With the patch applied:
     0.52%     0.12%  tcp_mmap  [kernel.kallsyms]  [k] __cgroup_bpf_run_filter_getsockopt_kern

Note, exporting uapi/tcp.h requires removing netinet/tcp.h
from test_progs.h because those headers have confliciting
definitions.

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20210115163501.805133-2-sdf@google.com
Stable-dep-of: 2598619e012c ("sctp: add bpf_bypass_getsockopt proto callback")
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Stanislav Fomichev
2021-01-15 08:34:59 -08:00
committed by Greg Kroah-Hartman
parent c62e2ac02e
commit 08f61a3491
16 changed files with 506 additions and 7 deletions
Download Patch File Download Diff File Expand all files Collapse all files

14
net/ipv4/tcp.c
View File

@@ -3970,6 +3970,8 @@ static int do_tcp_getsockopt(struct sock *sk, int level,
return -EFAULT;
lock_sock(sk);
err = tcp_zerocopy_receive(sk, &zc);
err = BPF_CGROUP_RUN_PROG_GETSOCKOPT_KERN(sk, level, optname,
&zc, &len, err);
release_sock(sk);
if (len >= offsetofend(struct tcp_zerocopy_receive, err))
goto zerocopy_rcv_sk_err;
@@ -4004,6 +4006,18 @@ zerocopy_rcv_out:
return 0;
}
bool tcp_bpf_bypass_getsockopt(int level, int optname)
{
/* TCP do_tcp_getsockopt has optimized getsockopt implementation
* to avoid extra socket lock for TCP_ZEROCOPY_RECEIVE.
*/
if (level == SOL_TCP && optname == TCP_ZEROCOPY_RECEIVE)
return true;
return false;
}
EXPORT_SYMBOL(tcp_bpf_bypass_getsockopt);
int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
int __user *optlen)
{