diff mbox series

[bpf-next,3/3] samples: bpf: refactor XDP kern program maps with BTF-defined map

Message ID 20201009160353.1529-4-danieltimlee@gmail.com (mailing list archive)
State Superseded
Delegated to: BPF
Headers show
Series samples: bpf: Refactor XDP programs with libbpf | expand

Commit Message

Daniel T. Lee Oct. 9, 2020, 4:03 p.m. UTC
Most of the samples were converted to use the new BTF-defined MAP as
they moved to libbpf, but some of the samples were missing.

Instead of using the previous BPF MAP definition, this commit refactors
xdp_monitor and xdp_sample_pkts_kern MAP definition with the new
BTF-defined MAP format.

Also, this commit removes the max_entries attribute at PERF_EVENT_ARRAY
map type. The libbpf's bpf_object__create_map() will automatically
set max_entries to the maximum configured number of CPUs on the host.

Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
---
 samples/bpf/xdp_monitor_kern.c     | 60 +++++++++++++++---------------
 samples/bpf/xdp_sample_pkts_kern.c | 14 +++----
 samples/bpf/xdp_sample_pkts_user.c |  1 -
 3 files changed, 36 insertions(+), 39 deletions(-)

Comments

Andrii Nakryiko Oct. 9, 2020, 6:25 p.m. UTC | #1
On Fri, Oct 9, 2020 at 9:04 AM Daniel T. Lee <danieltimlee@gmail.com> wrote:
>
> Most of the samples were converted to use the new BTF-defined MAP as
> they moved to libbpf, but some of the samples were missing.
>
> Instead of using the previous BPF MAP definition, this commit refactors
> xdp_monitor and xdp_sample_pkts_kern MAP definition with the new
> BTF-defined MAP format.
>
> Also, this commit removes the max_entries attribute at PERF_EVENT_ARRAY
> map type. The libbpf's bpf_object__create_map() will automatically
> set max_entries to the maximum configured number of CPUs on the host.
>
> Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
> ---
>  samples/bpf/xdp_monitor_kern.c     | 60 +++++++++++++++---------------
>  samples/bpf/xdp_sample_pkts_kern.c | 14 +++----
>  samples/bpf/xdp_sample_pkts_user.c |  1 -
>  3 files changed, 36 insertions(+), 39 deletions(-)
>

[...]

> --- a/samples/bpf/xdp_sample_pkts_kern.c
> +++ b/samples/bpf/xdp_sample_pkts_kern.c
> @@ -5,14 +5,12 @@
>  #include <bpf/bpf_helpers.h>
>
>  #define SAMPLE_SIZE 64ul
> -#define MAX_CPUS 128
> -
> -struct bpf_map_def SEC("maps") my_map = {
> -       .type = BPF_MAP_TYPE_PERF_EVENT_ARRAY,
> -       .key_size = sizeof(int),
> -       .value_size = sizeof(u32),
> -       .max_entries = MAX_CPUS,
> -};
> +
> +struct {
> +       __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
> +       __type(key, int);
> +       __type(value, u32);


this actually will generate unnecessary libbpf warnings, because
PERF_EVENT_ARRAY doesn't support BTF types for key/value. So use
__uint(key_size, sizeof(int)) and __uint(value_size, sizeof(u32))
instead.

> +} my_map SEC(".maps");
>
>  SEC("xdp_sample")
>  int xdp_sample_prog(struct xdp_md *ctx)
> diff --git a/samples/bpf/xdp_sample_pkts_user.c b/samples/bpf/xdp_sample_pkts_user.c
> index 991ef6f0880b..4b2a300c750c 100644
> --- a/samples/bpf/xdp_sample_pkts_user.c
> +++ b/samples/bpf/xdp_sample_pkts_user.c
> @@ -18,7 +18,6 @@
>
>  #include "perf-sys.h"
>
> -#define MAX_CPUS 128
>  static int if_idx;
>  static char *if_name;
>  static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
> --
> 2.25.1
>
Daniel T. Lee Oct. 10, 2020, 9:55 a.m. UTC | #2
On Sat, Oct 10, 2020 at 3:25 AM Andrii Nakryiko
<andrii.nakryiko@gmail.com> wrote:
>
> On Fri, Oct 9, 2020 at 9:04 AM Daniel T. Lee <danieltimlee@gmail.com> wrote:
> >
> > Most of the samples were converted to use the new BTF-defined MAP as
> > they moved to libbpf, but some of the samples were missing.
> >
> > Instead of using the previous BPF MAP definition, this commit refactors
> > xdp_monitor and xdp_sample_pkts_kern MAP definition with the new
> > BTF-defined MAP format.
> >
> > Also, this commit removes the max_entries attribute at PERF_EVENT_ARRAY
> > map type. The libbpf's bpf_object__create_map() will automatically
> > set max_entries to the maximum configured number of CPUs on the host.
> >
> > Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
> > ---
> >  samples/bpf/xdp_monitor_kern.c     | 60 +++++++++++++++---------------
> >  samples/bpf/xdp_sample_pkts_kern.c | 14 +++----
> >  samples/bpf/xdp_sample_pkts_user.c |  1 -
> >  3 files changed, 36 insertions(+), 39 deletions(-)
> >
>
> [...]
>
> > --- a/samples/bpf/xdp_sample_pkts_kern.c
> > +++ b/samples/bpf/xdp_sample_pkts_kern.c
> > @@ -5,14 +5,12 @@
> >  #include <bpf/bpf_helpers.h>
> >
> >  #define SAMPLE_SIZE 64ul
> > -#define MAX_CPUS 128
> > -
> > -struct bpf_map_def SEC("maps") my_map = {
> > -       .type = BPF_MAP_TYPE_PERF_EVENT_ARRAY,
> > -       .key_size = sizeof(int),
> > -       .value_size = sizeof(u32),
> > -       .max_entries = MAX_CPUS,
> > -};
> > +
> > +struct {
> > +       __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
> > +       __type(key, int);
> > +       __type(value, u32);
>
>
> this actually will generate unnecessary libbpf warnings, because
> PERF_EVENT_ARRAY doesn't support BTF types for key/value. So use
> __uint(key_size, sizeof(int)) and __uint(value_size, sizeof(u32))
> instead.
>

Thanks for the great review!
I'll fix it right away and send the next version of patch.


> > +} my_map SEC(".maps");
> >
> >  SEC("xdp_sample")
> >  int xdp_sample_prog(struct xdp_md *ctx)
> > diff --git a/samples/bpf/xdp_sample_pkts_user.c b/samples/bpf/xdp_sample_pkts_user.c
> > index 991ef6f0880b..4b2a300c750c 100644
> > --- a/samples/bpf/xdp_sample_pkts_user.c
> > +++ b/samples/bpf/xdp_sample_pkts_user.c
> > @@ -18,7 +18,6 @@
> >
> >  #include "perf-sys.h"
> >
> > -#define MAX_CPUS 128
> >  static int if_idx;
> >  static char *if_name;
> >  static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
> > --
> > 2.25.1
> >
diff mbox series

Patch

diff --git a/samples/bpf/xdp_monitor_kern.c b/samples/bpf/xdp_monitor_kern.c
index 3d33cca2d48a..5c955b812c47 100644
--- a/samples/bpf/xdp_monitor_kern.c
+++ b/samples/bpf/xdp_monitor_kern.c
@@ -6,21 +6,21 @@ 
 #include <uapi/linux/bpf.h>
 #include <bpf/bpf_helpers.h>
 
-struct bpf_map_def SEC("maps") redirect_err_cnt = {
-	.type = BPF_MAP_TYPE_PERCPU_ARRAY,
-	.key_size = sizeof(u32),
-	.value_size = sizeof(u64),
-	.max_entries = 2,
+struct {
+	__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
+	__type(key, u32);
+	__type(value, u64);
+	__uint(max_entries, 2);
 	/* TODO: have entries for all possible errno's */
-};
+} redirect_err_cnt SEC(".maps");
 
 #define XDP_UNKNOWN	XDP_REDIRECT + 1
-struct bpf_map_def SEC("maps") exception_cnt = {
-	.type		= BPF_MAP_TYPE_PERCPU_ARRAY,
-	.key_size	= sizeof(u32),
-	.value_size	= sizeof(u64),
-	.max_entries	= XDP_UNKNOWN + 1,
-};
+struct {
+	__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
+	__type(key, u32);
+	__type(value, u64);
+	__uint(max_entries, XDP_UNKNOWN + 1);
+} exception_cnt SEC(".maps");
 
 /* Tracepoint format: /sys/kernel/debug/tracing/events/xdp/xdp_redirect/format
  * Code in:                kernel/include/trace/events/xdp.h
@@ -129,19 +129,19 @@  struct datarec {
 };
 #define MAX_CPUS 64
 
-struct bpf_map_def SEC("maps") cpumap_enqueue_cnt = {
-	.type		= BPF_MAP_TYPE_PERCPU_ARRAY,
-	.key_size	= sizeof(u32),
-	.value_size	= sizeof(struct datarec),
-	.max_entries	= MAX_CPUS,
-};
+struct {
+	__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
+	__type(key, u32);
+	__type(value, struct datarec);
+	__uint(max_entries, MAX_CPUS);
+} cpumap_enqueue_cnt SEC(".maps");
 
-struct bpf_map_def SEC("maps") cpumap_kthread_cnt = {
-	.type		= BPF_MAP_TYPE_PERCPU_ARRAY,
-	.key_size	= sizeof(u32),
-	.value_size	= sizeof(struct datarec),
-	.max_entries	= 1,
-};
+struct {
+	__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
+	__type(key, u32);
+	__type(value, struct datarec);
+	__uint(max_entries, 1);
+} cpumap_kthread_cnt SEC(".maps");
 
 /* Tracepoint: /sys/kernel/debug/tracing/events/xdp/xdp_cpumap_enqueue/format
  * Code in:         kernel/include/trace/events/xdp.h
@@ -210,12 +210,12 @@  int trace_xdp_cpumap_kthread(struct cpumap_kthread_ctx *ctx)
 	return 0;
 }
 
-struct bpf_map_def SEC("maps") devmap_xmit_cnt = {
-	.type		= BPF_MAP_TYPE_PERCPU_ARRAY,
-	.key_size	= sizeof(u32),
-	.value_size	= sizeof(struct datarec),
-	.max_entries	= 1,
-};
+struct {
+	__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
+	__type(key, u32);
+	__type(value, struct datarec);
+	__uint(max_entries, 1);
+} devmap_xmit_cnt SEC(".maps");
 
 /* Tracepoint: /sys/kernel/debug/tracing/events/xdp/xdp_devmap_xmit/format
  * Code in:         kernel/include/trace/events/xdp.h
diff --git a/samples/bpf/xdp_sample_pkts_kern.c b/samples/bpf/xdp_sample_pkts_kern.c
index 33377289e2a8..2fc3ecc9d9aa 100644
--- a/samples/bpf/xdp_sample_pkts_kern.c
+++ b/samples/bpf/xdp_sample_pkts_kern.c
@@ -5,14 +5,12 @@ 
 #include <bpf/bpf_helpers.h>
 
 #define SAMPLE_SIZE 64ul
-#define MAX_CPUS 128
-
-struct bpf_map_def SEC("maps") my_map = {
-	.type = BPF_MAP_TYPE_PERF_EVENT_ARRAY,
-	.key_size = sizeof(int),
-	.value_size = sizeof(u32),
-	.max_entries = MAX_CPUS,
-};
+
+struct {
+	__uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
+	__type(key, int);
+	__type(value, u32);
+} my_map SEC(".maps");
 
 SEC("xdp_sample")
 int xdp_sample_prog(struct xdp_md *ctx)
diff --git a/samples/bpf/xdp_sample_pkts_user.c b/samples/bpf/xdp_sample_pkts_user.c
index 991ef6f0880b..4b2a300c750c 100644
--- a/samples/bpf/xdp_sample_pkts_user.c
+++ b/samples/bpf/xdp_sample_pkts_user.c
@@ -18,7 +18,6 @@ 
 
 #include "perf-sys.h"
 
-#define MAX_CPUS 128
 static int if_idx;
 static char *if_name;
 static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;