* [PATCH bpf-next] bpf: Remove bpf_get_smp_processor_id_proto
@ 2025-04-18 3:40 Feng Yang
2025-04-22 1:53 ` Alexei Starovoitov
0 siblings, 1 reply; 4+ messages in thread
From: Feng Yang @ 2025-04-18 3:40 UTC (permalink / raw)
To: ast, daniel, andrii, martin.lau, eddyz87, song, yonghong.song
Cc: bpf, linux-kernel, linux-trace-kernel, netdev, Feng Yang
From: Feng Yang <yangfeng@kylinos.cn>
All BPF programs either disable CPU preemption or CPU migration,
so the bpf_get_smp_processor_id_proto can be safely removed,
and the bpf_get_raw_smp_processor_id_proto in bpf_base_func_proto works perfectly.
Suggested-by: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Signed-off-by: Feng Yang <yangfeng@kylinos.cn>
---
include/linux/bpf.h | 1 -
kernel/bpf/core.c | 1 -
kernel/bpf/helpers.c | 12 ------------
kernel/trace/bpf_trace.c | 2 --
net/core/filter.c | 6 ------
5 files changed, 22 deletions(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 3f0cc89c0622..36e525141556 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -3316,7 +3316,6 @@ extern const struct bpf_func_proto bpf_map_peek_elem_proto;
extern const struct bpf_func_proto bpf_map_lookup_percpu_elem_proto;
extern const struct bpf_func_proto bpf_get_prandom_u32_proto;
-extern const struct bpf_func_proto bpf_get_smp_processor_id_proto;
extern const struct bpf_func_proto bpf_get_numa_node_id_proto;
extern const struct bpf_func_proto bpf_tail_call_proto;
extern const struct bpf_func_proto bpf_ktime_get_ns_proto;
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index ba6b6118cf50..1ad41a16b86e 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -2943,7 +2943,6 @@ const struct bpf_func_proto bpf_spin_unlock_proto __weak;
const struct bpf_func_proto bpf_jiffies64_proto __weak;
const struct bpf_func_proto bpf_get_prandom_u32_proto __weak;
-const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak;
const struct bpf_func_proto bpf_get_numa_node_id_proto __weak;
const struct bpf_func_proto bpf_ktime_get_ns_proto __weak;
const struct bpf_func_proto bpf_ktime_get_boot_ns_proto __weak;
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index e3a2662f4e33..2d2bfb2911f8 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -149,18 +149,6 @@ const struct bpf_func_proto bpf_get_prandom_u32_proto = {
.ret_type = RET_INTEGER,
};
-BPF_CALL_0(bpf_get_smp_processor_id)
-{
- return smp_processor_id();
-}
-
-const struct bpf_func_proto bpf_get_smp_processor_id_proto = {
- .func = bpf_get_smp_processor_id,
- .gpl_only = false,
- .ret_type = RET_INTEGER,
- .allow_fastcall = true,
-};
-
BPF_CALL_0(bpf_get_numa_node_id)
{
return numa_node_id();
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 0f5906f43d7c..39360cd6baf1 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -1462,8 +1462,6 @@ bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
return &bpf_get_current_comm_proto;
case BPF_FUNC_trace_printk:
return bpf_get_trace_printk_proto();
- case BPF_FUNC_get_smp_processor_id:
- return &bpf_get_smp_processor_id_proto;
case BPF_FUNC_get_numa_node_id:
return &bpf_get_numa_node_id_proto;
case BPF_FUNC_perf_event_read:
diff --git a/net/core/filter.c b/net/core/filter.c
index bc6828761a47..7f7ec913ddbc 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -8264,8 +8264,6 @@ tc_cls_act_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
return &bpf_set_hash_proto;
case BPF_FUNC_perf_event_output:
return &bpf_skb_event_output_proto;
- case BPF_FUNC_get_smp_processor_id:
- return &bpf_get_smp_processor_id_proto;
case BPF_FUNC_skb_under_cgroup:
return &bpf_skb_under_cgroup_proto;
case BPF_FUNC_get_socket_cookie:
@@ -8343,8 +8341,6 @@ xdp_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
switch (func_id) {
case BPF_FUNC_perf_event_output:
return &bpf_xdp_event_output_proto;
- case BPF_FUNC_get_smp_processor_id:
- return &bpf_get_smp_processor_id_proto;
case BPF_FUNC_csum_diff:
return &bpf_csum_diff_proto;
case BPF_FUNC_xdp_adjust_head:
@@ -8570,8 +8566,6 @@ lwt_out_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
return &bpf_get_hash_recalc_proto;
case BPF_FUNC_perf_event_output:
return &bpf_skb_event_output_proto;
- case BPF_FUNC_get_smp_processor_id:
- return &bpf_get_smp_processor_id_proto;
case BPF_FUNC_skb_under_cgroup:
return &bpf_skb_under_cgroup_proto;
default:
--
2.39.0.windows.2
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH bpf-next] bpf: Remove bpf_get_smp_processor_id_proto
2025-04-18 3:40 [PATCH bpf-next] bpf: Remove bpf_get_smp_processor_id_proto Feng Yang
@ 2025-04-22 1:53 ` Alexei Starovoitov
2025-04-22 8:04 ` Feng Yang
0 siblings, 1 reply; 4+ messages in thread
From: Alexei Starovoitov @ 2025-04-22 1:53 UTC (permalink / raw)
To: Feng Yang
Cc: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko,
Martin KaFai Lau, Eduard, Song Liu, Yonghong Song, bpf, LKML,
linux-trace-kernel, Network Development, Feng Yang
On Thu, Apr 17, 2025 at 8:41 PM Feng Yang <yangfeng59949@163.com> wrote:
>
> From: Feng Yang <yangfeng@kylinos.cn>
>
> All BPF programs either disable CPU preemption or CPU migration,
> so the bpf_get_smp_processor_id_proto can be safely removed,
> and the bpf_get_raw_smp_processor_id_proto in bpf_base_func_proto works perfectly.
>
> Suggested-by: Andrii Nakryiko <andrii.nakryiko@gmail.com>
> Signed-off-by: Feng Yang <yangfeng@kylinos.cn>
> ---
> include/linux/bpf.h | 1 -
> kernel/bpf/core.c | 1 -
> kernel/bpf/helpers.c | 12 ------------
> kernel/trace/bpf_trace.c | 2 --
> net/core/filter.c | 6 ------
> 5 files changed, 22 deletions(-)
>
> diff --git a/include/linux/bpf.h b/include/linux/bpf.h
> index 3f0cc89c0622..36e525141556 100644
> --- a/include/linux/bpf.h
> +++ b/include/linux/bpf.h
> @@ -3316,7 +3316,6 @@ extern const struct bpf_func_proto bpf_map_peek_elem_proto;
> extern const struct bpf_func_proto bpf_map_lookup_percpu_elem_proto;
>
> extern const struct bpf_func_proto bpf_get_prandom_u32_proto;
> -extern const struct bpf_func_proto bpf_get_smp_processor_id_proto;
> extern const struct bpf_func_proto bpf_get_numa_node_id_proto;
> extern const struct bpf_func_proto bpf_tail_call_proto;
> extern const struct bpf_func_proto bpf_ktime_get_ns_proto;
> diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
> index ba6b6118cf50..1ad41a16b86e 100644
> --- a/kernel/bpf/core.c
> +++ b/kernel/bpf/core.c
> @@ -2943,7 +2943,6 @@ const struct bpf_func_proto bpf_spin_unlock_proto __weak;
> const struct bpf_func_proto bpf_jiffies64_proto __weak;
>
> const struct bpf_func_proto bpf_get_prandom_u32_proto __weak;
> -const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak;
> const struct bpf_func_proto bpf_get_numa_node_id_proto __weak;
> const struct bpf_func_proto bpf_ktime_get_ns_proto __weak;
> const struct bpf_func_proto bpf_ktime_get_boot_ns_proto __weak;
> diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
> index e3a2662f4e33..2d2bfb2911f8 100644
> --- a/kernel/bpf/helpers.c
> +++ b/kernel/bpf/helpers.c
> @@ -149,18 +149,6 @@ const struct bpf_func_proto bpf_get_prandom_u32_proto = {
> .ret_type = RET_INTEGER,
> };
>
> -BPF_CALL_0(bpf_get_smp_processor_id)
> -{
> - return smp_processor_id();
> -}
> -
> -const struct bpf_func_proto bpf_get_smp_processor_id_proto = {
> - .func = bpf_get_smp_processor_id,
> - .gpl_only = false,
> - .ret_type = RET_INTEGER,
> - .allow_fastcall = true,
> -};
> -
bpf_get_raw_smp_processor_id_proto doesn't have
allow_fastcall = true
so this breaks tests.
Instead of removing BPF_CALL_0(bpf_get_smp_processor_id)
we should probably remove BPF_CALL_0(bpf_get_raw_cpu_id)
and adjust SKF_AD_OFF + SKF_AD_CPU case.
I don't recall why raw_ version was used back in 2014.
pw-bot: cr
^ permalink raw reply [flat|nested] 4+ messages in thread* (no subject)
2025-04-22 1:53 ` Alexei Starovoitov
@ 2025-04-22 8:04 ` Feng Yang
2025-04-22 14:37 ` Alexei Starovoitov
0 siblings, 1 reply; 4+ messages in thread
From: Feng Yang @ 2025-04-22 8:04 UTC (permalink / raw)
To: alexei.starovoitov
Cc: andrii, ast, bpf, daniel, eddyz87, linux-kernel,
linux-trace-kernel, martin.lau, netdev, song, yangfeng59949,
yangfeng, yonghong.song
Subject: Re: [PATCH bpf-next] bpf: Remove bpf_get_smp_processor_id_proto
On Mon, 21 Apr 2025 18:53:07 -0700 Alexei Starovoitov <alexei.starovoitov@gmail.com> wrote:
> On Thu, Apr 17, 2025 at 8:41 PM Feng Yang <yangfeng59949@163.com> wrote:
> >
> > From: Feng Yang <yangfeng@kylinos.cn>
> >
> > All BPF programs either disable CPU preemption or CPU migration,
> > so the bpf_get_smp_processor_id_proto can be safely removed,
> > and the bpf_get_raw_smp_processor_id_proto in bpf_base_func_proto works perfectly.
> >
> > Suggested-by: Andrii Nakryiko <andrii.nakryiko@gmail.com>
> > Signed-off-by: Feng Yang <yangfeng@kylinos.cn>
> > ---
> > include/linux/bpf.h | 1 -
> > kernel/bpf/core.c | 1 -
> > kernel/bpf/helpers.c | 12 ------------
> > kernel/trace/bpf_trace.c | 2 --
> > net/core/filter.c | 6 ------
> > 5 files changed, 22 deletions(-)
> >
> > diff --git a/include/linux/bpf.h b/include/linux/bpf.h
> > index 3f0cc89c0622..36e525141556 100644
> > --- a/include/linux/bpf.h
> > +++ b/include/linux/bpf.h
> > @@ -3316,7 +3316,6 @@ extern const struct bpf_func_proto bpf_map_peek_elem_proto;
> > extern const struct bpf_func_proto bpf_map_lookup_percpu_elem_proto;
> >
> > extern const struct bpf_func_proto bpf_get_prandom_u32_proto;
> > -extern const struct bpf_func_proto bpf_get_smp_processor_id_proto;
> > extern const struct bpf_func_proto bpf_get_numa_node_id_proto;
> > extern const struct bpf_func_proto bpf_tail_call_proto;
> > extern const struct bpf_func_proto bpf_ktime_get_ns_proto;
> > diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
> > index ba6b6118cf50..1ad41a16b86e 100644
> > --- a/kernel/bpf/core.c
> > +++ b/kernel/bpf/core.c
> > @@ -2943,7 +2943,6 @@ const struct bpf_func_proto bpf_spin_unlock_proto __weak;
> > const struct bpf_func_proto bpf_jiffies64_proto __weak;
> >
> > const struct bpf_func_proto bpf_get_prandom_u32_proto __weak;
> > -const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak;
> > const struct bpf_func_proto bpf_get_numa_node_id_proto __weak;
> > const struct bpf_func_proto bpf_ktime_get_ns_proto __weak;
> > const struct bpf_func_proto bpf_ktime_get_boot_ns_proto __weak;
> > diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
> > index e3a2662f4e33..2d2bfb2911f8 100644
> > --- a/kernel/bpf/helpers.c
> > +++ b/kernel/bpf/helpers.c
> > @@ -149,18 +149,6 @@ const struct bpf_func_proto bpf_get_prandom_u32_proto = {
> > .ret_type = RET_INTEGER,
> > };
> >
> > -BPF_CALL_0(bpf_get_smp_processor_id)
> > -{
> > - return smp_processor_id();
> > -}
> > -
> > -const struct bpf_func_proto bpf_get_smp_processor_id_proto = {
> > - .func = bpf_get_smp_processor_id,
> > - .gpl_only = false,
> > - .ret_type = RET_INTEGER,
> > - .allow_fastcall = true,
> > -};
> > -
>
> bpf_get_raw_smp_processor_id_proto doesn't have
> allow_fastcall = true
>
> so this breaks tests.
>
> Instead of removing BPF_CALL_0(bpf_get_smp_processor_id)
> we should probably remove BPF_CALL_0(bpf_get_raw_cpu_id)
> and adjust SKF_AD_OFF + SKF_AD_CPU case.
> I don't recall why raw_ version was used back in 2014.
>
The following two seem to explain the reason:
https://lore.kernel.org/all/7103e2085afa29c006cd5b94a6e4a2ac83efc30d.1467106475.git.daniel@iogearbox.net/
https://lore.kernel.org/all/02fa71ebe1c560cad489967aa29c653b48932596.1474586162.git.daniel@iogearbox.net/
^ permalink raw reply [flat|nested] 4+ messages in thread* Re:
2025-04-22 8:04 ` Feng Yang
@ 2025-04-22 14:37 ` Alexei Starovoitov
0 siblings, 0 replies; 4+ messages in thread
From: Alexei Starovoitov @ 2025-04-22 14:37 UTC (permalink / raw)
To: Feng Yang
Cc: Andrii Nakryiko, Alexei Starovoitov, bpf, Daniel Borkmann, Eduard,
LKML, linux-trace-kernel, Martin KaFai Lau, Network Development,
Song Liu, Feng Yang, Yonghong Song
On Tue, Apr 22, 2025 at 1:04 AM Feng Yang <yangfeng59949@163.com> wrote:
>
> Subject: Re: [PATCH bpf-next] bpf: Remove bpf_get_smp_processor_id_proto
>
> On Mon, 21 Apr 2025 18:53:07 -0700 Alexei Starovoitov <alexei.starovoitov@gmail.com> wrote:
>
> > On Thu, Apr 17, 2025 at 8:41 PM Feng Yang <yangfeng59949@163.com> wrote:
> > >
> > > From: Feng Yang <yangfeng@kylinos.cn>
> > >
> > > All BPF programs either disable CPU preemption or CPU migration,
> > > so the bpf_get_smp_processor_id_proto can be safely removed,
> > > and the bpf_get_raw_smp_processor_id_proto in bpf_base_func_proto works perfectly.
> > >
> > > Suggested-by: Andrii Nakryiko <andrii.nakryiko@gmail.com>
> > > Signed-off-by: Feng Yang <yangfeng@kylinos.cn>
> > > ---
> > > include/linux/bpf.h | 1 -
> > > kernel/bpf/core.c | 1 -
> > > kernel/bpf/helpers.c | 12 ------------
> > > kernel/trace/bpf_trace.c | 2 --
> > > net/core/filter.c | 6 ------
> > > 5 files changed, 22 deletions(-)
> > >
> > > diff --git a/include/linux/bpf.h b/include/linux/bpf.h
> > > index 3f0cc89c0622..36e525141556 100644
> > > --- a/include/linux/bpf.h
> > > +++ b/include/linux/bpf.h
> > > @@ -3316,7 +3316,6 @@ extern const struct bpf_func_proto bpf_map_peek_elem_proto;
> > > extern const struct bpf_func_proto bpf_map_lookup_percpu_elem_proto;
> > >
> > > extern const struct bpf_func_proto bpf_get_prandom_u32_proto;
> > > -extern const struct bpf_func_proto bpf_get_smp_processor_id_proto;
> > > extern const struct bpf_func_proto bpf_get_numa_node_id_proto;
> > > extern const struct bpf_func_proto bpf_tail_call_proto;
> > > extern const struct bpf_func_proto bpf_ktime_get_ns_proto;
> > > diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
> > > index ba6b6118cf50..1ad41a16b86e 100644
> > > --- a/kernel/bpf/core.c
> > > +++ b/kernel/bpf/core.c
> > > @@ -2943,7 +2943,6 @@ const struct bpf_func_proto bpf_spin_unlock_proto __weak;
> > > const struct bpf_func_proto bpf_jiffies64_proto __weak;
> > >
> > > const struct bpf_func_proto bpf_get_prandom_u32_proto __weak;
> > > -const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak;
> > > const struct bpf_func_proto bpf_get_numa_node_id_proto __weak;
> > > const struct bpf_func_proto bpf_ktime_get_ns_proto __weak;
> > > const struct bpf_func_proto bpf_ktime_get_boot_ns_proto __weak;
> > > diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
> > > index e3a2662f4e33..2d2bfb2911f8 100644
> > > --- a/kernel/bpf/helpers.c
> > > +++ b/kernel/bpf/helpers.c
> > > @@ -149,18 +149,6 @@ const struct bpf_func_proto bpf_get_prandom_u32_proto = {
> > > .ret_type = RET_INTEGER,
> > > };
> > >
> > > -BPF_CALL_0(bpf_get_smp_processor_id)
> > > -{
> > > - return smp_processor_id();
> > > -}
> > > -
> > > -const struct bpf_func_proto bpf_get_smp_processor_id_proto = {
> > > - .func = bpf_get_smp_processor_id,
> > > - .gpl_only = false,
> > > - .ret_type = RET_INTEGER,
> > > - .allow_fastcall = true,
> > > -};
> > > -
> >
> > bpf_get_raw_smp_processor_id_proto doesn't have
> > allow_fastcall = true
> >
> > so this breaks tests.
> >
> > Instead of removing BPF_CALL_0(bpf_get_smp_processor_id)
> > we should probably remove BPF_CALL_0(bpf_get_raw_cpu_id)
> > and adjust SKF_AD_OFF + SKF_AD_CPU case.
> > I don't recall why raw_ version was used back in 2014.
> >
>
> The following two seem to explain the reason:
> https://lore.kernel.org/all/7103e2085afa29c006cd5b94a6e4a2ac83efc30d.1467106475.git.daniel@iogearbox.net/
> https://lore.kernel.org/all/02fa71ebe1c560cad489967aa29c653b48932596.1474586162.git.daniel@iogearbox.net/
>
Ahh. socket filters run in RCU CS. They don't disable preemption or migration.
Then let's keep things as-is.
We still want debugging provided by smp_processor_id().
If we switch everything to raw_ may miss things. Like this example with
socket filters.
^ permalink raw reply [flat|nested] 4+ messages in thread
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2025-04-18 3:40 [PATCH bpf-next] bpf: Remove bpf_get_smp_processor_id_proto Feng Yang
2025-04-22 1:53 ` Alexei Starovoitov
2025-04-22 8:04 ` Feng Yang
2025-04-22 14:37 ` Alexei Starovoitov
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