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Commit 3792cb2f authored by Song Liu's avatar Song Liu Committed by Arnaldo Carvalho de Melo
Browse files

perf bpf: Save BTF in a rbtree in perf_env 



BTF contains information necessary to annotate BPF programs. This patch
saves BTF for BPF programs loaded in the system.

Signed-off-by: default avatarSong Liu <songliubraving@fb.com>
Reviewed-by: default avatarJiri Olsa <jolsa@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stanislav Fomichev <sdf@google.com>
Cc: kernel-team@fb.com
Link: http://lkml.kernel.org/r/20190312053051.2690567-9-songliubraving@fb.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 606f972b

tools/perf/util/bpf-event.c

+23 −0
Original line number Diff line number Diff line
@@ -34,6 +34,28 @@ int machine__process_bpf_event(struct machine *machine __maybe_unused, 
	return 0;

}



static int perf_env__fetch_btf(struct perf_env *env,

			       u32 btf_id,

			       struct btf *btf)

{

	struct btf_node *node;

	u32 data_size;

	const void *data;



	data = btf__get_raw_data(btf, &data_size);



	node = malloc(data_size + sizeof(struct btf_node));

	if (!node)

		return -1;



	node->id = btf_id;

	node->data_size = data_size;

	memcpy(node->data, data, data_size);



	perf_env__insert_btf(env, node);

	return 0;

}



/*

 * Synthesize PERF_RECORD_KSYMBOL and PERF_RECORD_BPF_EVENT for one bpf

 * program. One PERF_RECORD_BPF_EVENT is generated for the program. And
@@ -113,6 +135,7 @@ static int perf_event__synthesize_one_bpf_prog(struct perf_session *session, 
			goto out;

		}

		has_btf = true;

		perf_env__fetch_btf(env, info->btf_id, btf);

	}



	/* Synthesize PERF_RECORD_KSYMBOL */

tools/perf/util/bpf-event.h

+7 −0
Original line number Diff line number Diff line
@@ -16,6 +16,13 @@ struct bpf_prog_info_node { 
	struct rb_node			rb_node;

};



struct btf_node {

	struct rb_node	rb_node;

	u32		id;

	u32		data_size;

	char		data[];

};



#ifdef HAVE_LIBBPF_SUPPORT

int machine__process_bpf_event(struct machine *machine, union perf_event *event,

			       struct perf_sample *sample);

tools/perf/util/env.c

+67 −0
Original line number Diff line number Diff line
@@ -64,6 +64,58 @@ struct bpf_prog_info_node *perf_env__find_bpf_prog_info(struct perf_env *env, 
	return node;

}



void perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node)

{

	struct rb_node *parent = NULL;

	__u32 btf_id = btf_node->id;

	struct btf_node *node;

	struct rb_node **p;



	down_write(&env->bpf_progs.lock);

	p = &env->bpf_progs.btfs.rb_node;



	while (*p != NULL) {

		parent = *p;

		node = rb_entry(parent, struct btf_node, rb_node);

		if (btf_id < node->id) {

			p = &(*p)->rb_left;

		} else if (btf_id > node->id) {

			p = &(*p)->rb_right;

		} else {

			pr_debug("duplicated btf %u\n", btf_id);

			goto out;

		}

	}



	rb_link_node(&btf_node->rb_node, parent, p);

	rb_insert_color(&btf_node->rb_node, &env->bpf_progs.btfs);

	env->bpf_progs.btfs_cnt++;

out:

	up_write(&env->bpf_progs.lock);

}



struct btf_node *perf_env__find_btf(struct perf_env *env, __u32 btf_id)

{

	struct btf_node *node = NULL;

	struct rb_node *n;



	down_read(&env->bpf_progs.lock);

	n = env->bpf_progs.btfs.rb_node;



	while (n) {

		node = rb_entry(n, struct btf_node, rb_node);

		if (btf_id < node->id)

			n = n->rb_left;

		else if (btf_id > node->id)

			n = n->rb_right;

		else

			break;

	}



	up_read(&env->bpf_progs.lock);

	return node;

}



/* purge data in bpf_progs.infos tree */

static void perf_env__purge_bpf(struct perf_env *env)

{
@@ -86,6 +138,20 @@ static void perf_env__purge_bpf(struct perf_env *env) 


	env->bpf_progs.infos_cnt = 0;



	root = &env->bpf_progs.btfs;

	next = rb_first(root);



	while (next) {

		struct btf_node *node;



		node = rb_entry(next, struct btf_node, rb_node);

		next = rb_next(&node->rb_node);

		rb_erase(&node->rb_node, root);

		free(node);

	}



	env->bpf_progs.btfs_cnt = 0;



	up_write(&env->bpf_progs.lock);

}
@@ -123,6 +189,7 @@ void perf_env__exit(struct perf_env *env) 
void perf_env__init(struct perf_env *env)

{

	env->bpf_progs.infos = RB_ROOT;

	env->bpf_progs.btfs = RB_ROOT;

	init_rwsem(&env->bpf_progs.lock);

}

tools/perf/util/env.h

+5 −0
Original line number Diff line number Diff line
@@ -75,10 +75,13 @@ struct perf_env { 
		struct rw_semaphore	lock;

		struct rb_root		infos;

		u32			infos_cnt;

		struct rb_root		btfs;

		u32			btfs_cnt;

	} bpf_progs;

};



struct bpf_prog_info_node;

struct btf_node;



extern struct perf_env perf_env;
@@ -99,4 +102,6 @@ void perf_env__insert_bpf_prog_info(struct perf_env *env, 
				    struct bpf_prog_info_node *info_node);

struct bpf_prog_info_node *perf_env__find_bpf_prog_info(struct perf_env *env,

							__u32 prog_id);

void perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node);

struct btf_node *perf_env__find_btf(struct perf_env *env, __u32 btf_id);

#endif /* __PERF_ENV_H */