diff mbox series

[bpf-next,14/15] bpf: selftest: bpf_cubic and bpf_dctcp calling kernel functions

Message ID 20210316011503.4181087-1-kafai@fb.com (mailing list archive)
State Changes Requested
Delegated to: BPF
Headers show
Series Support calling kernel function | expand

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netdev/cc_maintainers warning 10 maintainers not CCed: linux-kselftest@vger.kernel.org yhs@fb.com kpsingh@kernel.org andrii@kernel.org ncardwell@google.com john.fastabend@gmail.com songliubraving@fb.com davem@davemloft.net shuah@kernel.org edumazet@google.com
netdev/source_inline success Was 0 now: 0
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netdev/module_param success Was 0 now: 0
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
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netdev/checkpatch warning CHECK: extern prototypes should be avoided in .h files
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Commit Message

Martin KaFai Lau March 16, 2021, 1:15 a.m. UTC 
This patch removes the bpf implementation of tcp_slow_start()
and tcp_cong_avoid_ai().  Instead, it directly uses the kernel
implementation.

It also replaces the bpf_cubic_undo_cwnd implementation by directly
calling tcp_reno_undo_cwnd().  bpf_dctcp also directly calls
tcp_reno_cong_avoid() instead.

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
---
 tools/testing/selftests/bpf/bpf_tcp_helpers.h | 29 ++-----------------
 tools/testing/selftests/bpf/progs/bpf_cubic.c |  6 ++--
 tools/testing/selftests/bpf/progs/bpf_dctcp.c | 22 ++++----------
 3 files changed, 11 insertions(+), 46 deletions(-)

Comments

Andrii Nakryiko March 19, 2021, 4:15 a.m. UTC | #1 
On Tue, Mar 16, 2021 at 12:02 AM Martin KaFai Lau <kafai@fb.com> wrote:
>
> This patch removes the bpf implementation of tcp_slow_start()
> and tcp_cong_avoid_ai().  Instead, it directly uses the kernel
> implementation.
>
> It also replaces the bpf_cubic_undo_cwnd implementation by directly
> calling tcp_reno_undo_cwnd().  bpf_dctcp also directly calls
> tcp_reno_cong_avoid() instead.
>
> Signed-off-by: Martin KaFai Lau <kafai@fb.com>
> ---

This is awesome.

Acked-by: Andrii Nakryiko <andrii@kernel.org>

>  tools/testing/selftests/bpf/bpf_tcp_helpers.h | 29 ++-----------------
>  tools/testing/selftests/bpf/progs/bpf_cubic.c |  6 ++--
>  tools/testing/selftests/bpf/progs/bpf_dctcp.c | 22 ++++----------
>  3 files changed, 11 insertions(+), 46 deletions(-)
>

[...]
diff mbox series

Patch

diff --git a/tools/testing/selftests/bpf/bpf_tcp_helpers.h b/tools/testing/selftests/bpf/bpf_tcp_helpers.h
index 91f0fac632f4..029589c008c9 100644
--- a/tools/testing/selftests/bpf/bpf_tcp_helpers.h
+++ b/tools/testing/selftests/bpf/bpf_tcp_helpers.h
@@ -187,16 +187,6 @@  struct tcp_congestion_ops {
 	typeof(y) __y = (y);			\
 	__x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); })
 
-static __always_inline __u32 tcp_slow_start(struct tcp_sock *tp, __u32 acked)
-{
-	__u32 cwnd = min(tp->snd_cwnd + acked, tp->snd_ssthresh);
-
-	acked -= cwnd - tp->snd_cwnd;
-	tp->snd_cwnd = min(cwnd, tp->snd_cwnd_clamp);
-
-	return acked;
-}
-
 static __always_inline bool tcp_in_slow_start(const struct tcp_sock *tp)
 {
 	return tp->snd_cwnd < tp->snd_ssthresh;
@@ -213,22 +203,7 @@  static __always_inline bool tcp_is_cwnd_limited(const struct sock *sk)
 	return !!BPF_CORE_READ_BITFIELD(tp, is_cwnd_limited);
 }
 
-static __always_inline void tcp_cong_avoid_ai(struct tcp_sock *tp, __u32 w, __u32 acked)
-{
-	/* If credits accumulated at a higher w, apply them gently now. */
-	if (tp->snd_cwnd_cnt >= w) {
-		tp->snd_cwnd_cnt = 0;
-		tp->snd_cwnd++;
-	}
-
-	tp->snd_cwnd_cnt += acked;
-	if (tp->snd_cwnd_cnt >= w) {
-		__u32 delta = tp->snd_cwnd_cnt / w;
-
-		tp->snd_cwnd_cnt -= delta * w;
-		tp->snd_cwnd += delta;
-	}
-	tp->snd_cwnd = min(tp->snd_cwnd, tp->snd_cwnd_clamp);
-}
+extern __u32 tcp_slow_start(struct tcp_sock *tp, __u32 acked) __ksym;
+extern void tcp_cong_avoid_ai(struct tcp_sock *tp, __u32 w, __u32 acked) __ksym;
 
 #endif
diff --git a/tools/testing/selftests/bpf/progs/bpf_cubic.c b/tools/testing/selftests/bpf/progs/bpf_cubic.c
index 33c4d2bded64..f62df4d023f9 100644
--- a/tools/testing/selftests/bpf/progs/bpf_cubic.c
+++ b/tools/testing/selftests/bpf/progs/bpf_cubic.c
@@ -525,11 +525,11 @@  void BPF_STRUCT_OPS(bpf_cubic_acked, struct sock *sk,
 		hystart_update(sk, delay);
 }
 
+extern __u32 tcp_reno_undo_cwnd(struct sock *sk) __ksym;
+
 __u32 BPF_STRUCT_OPS(bpf_cubic_undo_cwnd, struct sock *sk)
 {
-	const struct tcp_sock *tp = tcp_sk(sk);
-
-	return max(tp->snd_cwnd, tp->prior_cwnd);
+	return tcp_reno_undo_cwnd(sk);
 }
 
 SEC(".struct_ops")
diff --git a/tools/testing/selftests/bpf/progs/bpf_dctcp.c b/tools/testing/selftests/bpf/progs/bpf_dctcp.c
index 4dc1a967776a..fd42247da8b4 100644
--- a/tools/testing/selftests/bpf/progs/bpf_dctcp.c
+++ b/tools/testing/selftests/bpf/progs/bpf_dctcp.c
@@ -194,22 +194,12 @@  __u32 BPF_PROG(dctcp_cwnd_undo, struct sock *sk)
 	return max(tcp_sk(sk)->snd_cwnd, ca->loss_cwnd);
 }
 
-SEC("struct_ops/tcp_reno_cong_avoid")
-void BPF_PROG(tcp_reno_cong_avoid, struct sock *sk, __u32 ack, __u32 acked)
-{
-	struct tcp_sock *tp = tcp_sk(sk);
-
-	if (!tcp_is_cwnd_limited(sk))
-		return;
+extern void tcp_reno_cong_avoid(struct sock *sk, __u32 ack, __u32 acked) __ksym;
 
-	/* In "safe" area, increase. */
-	if (tcp_in_slow_start(tp)) {
-		acked = tcp_slow_start(tp, acked);
-		if (!acked)
-			return;
-	}
-	/* In dangerous area, increase slowly. */
-	tcp_cong_avoid_ai(tp, tp->snd_cwnd, acked);
+SEC("struct_ops/dctcp_reno_cong_avoid")
+void BPF_PROG(dctcp_cong_avoid, struct sock *sk, __u32 ack, __u32 acked)
+{
+	tcp_reno_cong_avoid(sk, ack, acked);
 }
 
 SEC(".struct_ops")
@@ -226,7 +216,7 @@  struct tcp_congestion_ops dctcp = {
 	.in_ack_event   = (void *)dctcp_update_alpha,
 	.cwnd_event	= (void *)dctcp_cwnd_event,
 	.ssthresh	= (void *)dctcp_ssthresh,
-	.cong_avoid	= (void *)tcp_reno_cong_avoid,
+	.cong_avoid	= (void *)dctcp_cong_avoid,
 	.undo_cwnd	= (void *)dctcp_cwnd_undo,
 	.set_state	= (void *)dctcp_state,
 	.flags		= TCP_CONG_NEEDS_ECN,