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SubjectRe: [PATCH v2 perf,bpf 07/11] perf, bpf: save btf in a rbtree in perf_env
Em Thu, Feb 14, 2019 at 04:00:08PM -0800, Song Liu escreveu:
> btf contains information necessary to annotate bpf programs. This patch
> saves btf for bpf programs loaded in the system.
>
> Signed-off-by: Song Liu <songliubraving@fb.com>
> ---
> tools/perf/util/bpf-event.c | 22 +++++++++++++
> tools/perf/util/bpf-event.h | 7 ++++
> tools/perf/util/env.c | 65 +++++++++++++++++++++++++++++++++++++
> tools/perf/util/env.h | 3 ++
> 4 files changed, 97 insertions(+)
>
> diff --git a/tools/perf/util/bpf-event.c b/tools/perf/util/bpf-event.c
> index ead599bc4f4e..37a5b8134e00 100644
> --- a/tools/perf/util/bpf-event.c
> +++ b/tools/perf/util/bpf-event.c
> @@ -30,6 +30,27 @@ int machine__process_bpf_event(struct machine *machine __maybe_unused,
> return 0;
> }
>
> +static int perf_fetch_btf(struct perf_env *env, u32 btf_id, struct btf *btf)

Please use perf_env__fetch_bpf

> +{
> + 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);

Just like you did above :-)

> + 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
> @@ -109,6 +130,7 @@ static int perf_event__synthesize_one_bpf_prog(struct perf_session *session,
> goto out;
> }
> has_btf = true;
> + perf_fetch_btf(env, info->btf_id, btf);
> }
>
> /* Synthesize PERF_RECORD_KSYMBOL */
> diff --git a/tools/perf/util/bpf-event.h b/tools/perf/util/bpf-event.h
> index 11e6730b6105..60ce24e4e5c6 100644
> --- a/tools/perf/util/bpf-event.h
> +++ b/tools/perf/util/bpf-event.h
> @@ -20,6 +20,13 @@ 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);
> diff --git a/tools/perf/util/env.c b/tools/perf/util/env.c
> index 665b6fe3c7b2..6f9e3d4b94bc 100644
> --- a/tools/perf/util/env.c
> +++ b/tools/perf/util/env.c
> @@ -61,6 +61,57 @@ 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_info_lock);
> + p = &env->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:

> + up_write(&env->bpf_info_lock);
> + return;
> + }
> + }
> +
> + rb_link_node(&btf_node->rb_node, parent, p);
> + rb_insert_color(&btf_node->rb_node, &env->btfs);
out:
> + up_write(&env->bpf_info_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_info_lock);
> + n = env->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_info_lock);
> + return node;
> +}
> +
> /* purge data in bpf_prog_infos tree */
> static void purge_bpf_info(struct perf_env *env)

The above should've been perf_env__purge_bpf()

> {
> @@ -80,6 +131,19 @@ static void purge_bpf_info(struct perf_env *env)
> rb_erase_init(&node->rb_node, root);
> free(node);
> }
> +
> + root = &env->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_init(&node->rb_node, root);
> + free(node);
> + }
> +
> up_write(&env->bpf_info_lock);
> }
>
> @@ -117,6 +181,7 @@ void perf_env__exit(struct perf_env *env)
> static void init_bpf_rb_trees(struct perf_env *env)
> {
> env->bpf_prog_infos = RB_ROOT;
> + env->btfs = RB_ROOT;
> init_rwsem(&env->bpf_info_lock);
> }
>
> diff --git a/tools/perf/util/env.h b/tools/perf/util/env.h
> index a6d25e91bc98..f0c74255423c 100644
> --- a/tools/perf/util/env.h
> +++ b/tools/perf/util/env.h
> @@ -74,6 +74,7 @@ struct perf_env {
> */
> struct rw_semaphore bpf_info_lock;
> struct rb_root bpf_prog_infos;
> + struct rb_root btfs;
> };
>
> extern struct perf_env perf_env;
> @@ -94,4 +95,6 @@ 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 */
> --
> 2.17.1

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