Commit 321f6324 authored by Daniel T. Lee's avatar Daniel T. Lee Committed by Alexei Starovoitov
Browse files

samples: bpf: Refactor XDP kern program maps with BTF-defined map 



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: default avatarDaniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20201010181734.1109-4-danieltimlee@gmail.com
parent 151936bf

samples/bpf/xdp_monitor_kern.c

+30 −30
Original line number Diff line number Diff line
@@ -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

samples/bpf/xdp_sample_pkts_kern.c

+6 −8
Original line number Diff line number Diff line
@@ -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);

	__uint(key_size, sizeof(int));

	__uint(value_size, sizeof(u32));

} my_map SEC(".maps");



SEC("xdp_sample")

int xdp_sample_prog(struct xdp_md *ctx)

samples/bpf/xdp_sample_pkts_user.c

+0 −1
Original line number Diff line number Diff line
@@ -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;

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