Re: [PATCH v2 perf,bpf 05/11] perf, bpf: save bpf_prog_info in a rbtree in perf_env

From: Arnaldo Carvalho de Melo
Date: Fri Feb 15 2019 - 09:22:06 EST

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Em Thu, Feb 14, 2019 at 04:00:06PM -0800, Song Liu escreveu:
> bpf_prog_info contains information necessary to annotate bpf programs.
> This patch saves bpf_prog_info for bpf programs loaded in the system.
>
> Signed-off-by: Song Liu <songliubraving@xxxxxx>
> ---
> tools/perf/builtin-record.c | 2 +-
> tools/perf/builtin-top.c | 2 +-
> tools/perf/util/bpf-event.c | 39 +++++++++++++----
> tools/perf/util/bpf-event.h | 15 +++++--
> tools/perf/util/env.c | 83 +++++++++++++++++++++++++++++++++++++
> tools/perf/util/env.h | 14 +++++++
> 6 files changed, 142 insertions(+), 13 deletions(-)
>
> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index 88ea11d57c6f..2355e0a9eda0 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -1083,7 +1083,7 @@ static int record__synthesize(struct record *rec, bool tail)
> return err;
> }
>
> - err = perf_event__synthesize_bpf_events(tool, process_synthesized_event,
> + err = perf_event__synthesize_bpf_events(session, process_synthesized_event,
> machine, opts);
> if (err < 0)
> pr_warning("Couldn't synthesize bpf events.\n");
> diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
> index 5a486d4de56e..27d8d42e0a4d 100644
> --- a/tools/perf/builtin-top.c
> +++ b/tools/perf/builtin-top.c
> @@ -1216,7 +1216,7 @@ static int __cmd_top(struct perf_top *top)
>
> init_process_thread(top);
>
> - ret = perf_event__synthesize_bpf_events(&top->tool, perf_event__process,
> + ret = perf_event__synthesize_bpf_events(top->session, perf_event__process,
> &top->session->machines.host,
> &top->record_opts);
> if (ret < 0)
> diff --git a/tools/perf/util/bpf-event.c b/tools/perf/util/bpf-event.c
> index e6dfb95029e5..ead599bc4f4e 100644
> --- a/tools/perf/util/bpf-event.c
> +++ b/tools/perf/util/bpf-event.c
> @@ -1,15 +1,13 @@
> // SPDX-License-Identifier: GPL-2.0
> #include <errno.h>
> #include <stdlib.h>
> -#include <bpf/bpf.h>
> -#include <bpf/btf.h>
> -#include <bpf/libbpf.h>
> -#include <linux/btf.h>

I think you need these here, since in this C file you will use the
definitions for these structs, see further comments below.

> #include <linux/err.h>
> #include "bpf-event.h"
> #include "debug.h"
> #include "symbol.h"
> #include "machine.h"
> +#include "env.h"
> +#include "session.h"
>
> #define ptr_to_u64(ptr) ((__u64)(unsigned long)(ptr))
>
> @@ -42,7 +40,7 @@ int machine__process_bpf_event(struct machine *machine __maybe_unused,
> * -1 for failures;
> * -2 for lack of kernel support.
> */
> -static int perf_event__synthesize_one_bpf_prog(struct perf_tool *tool,
> +static int perf_event__synthesize_one_bpf_prog(struct perf_session *session,
> perf_event__handler_t process,
> struct machine *machine,
> int fd,
> @@ -52,17 +50,29 @@ static int perf_event__synthesize_one_bpf_prog(struct perf_tool *tool,
> struct ksymbol_event *ksymbol_event = &event->ksymbol_event;
> struct bpf_event *bpf_event = &event->bpf_event;
> struct bpf_prog_info_linear *info_linear;
> + struct perf_tool *tool = session->tool;
> + struct bpf_prog_info_node *info_node;
> struct bpf_prog_info *info;
> struct btf *btf = NULL;
> bool has_btf = false;
> + struct perf_env *env;
> u32 sub_prog_cnt, i;
> int err = 0;
> u64 arrays;
>
> + /*
> + * for perf-record and perf-report use header.env;
> + * otherwise, use global perf_env.
> + */
> + env = session->data ? &session->header.env : &perf_env;
> +
> arrays = 1UL << BPF_PROG_INFO_JITED_KSYMS;
> arrays |= 1UL << BPF_PROG_INFO_JITED_FUNC_LENS;
> arrays |= 1UL << BPF_PROG_INFO_FUNC_INFO;
> arrays |= 1UL << BPF_PROG_INFO_PROG_TAGS;
> + arrays |= 1UL << BPF_PROG_INFO_JITED_INSNS;
> + arrays |= 1UL << BPF_PROG_INFO_LINE_INFO;
> + arrays |= 1UL << BPF_PROG_INFO_JITED_LINE_INFO;
>
> info_linear = bpf_program__get_prog_info_linear(fd, arrays);
> if (IS_ERR_OR_NULL(info_linear)) {
> @@ -151,8 +161,8 @@ static int perf_event__synthesize_one_bpf_prog(struct perf_tool *tool,
> machine, process);
> }
>
> - /* Synthesize PERF_RECORD_BPF_EVENT */
> if (opts->bpf_event) {
> + /* Synthesize PERF_RECORD_BPF_EVENT */
> *bpf_event = (struct bpf_event){
> .header = {
> .type = PERF_RECORD_BPF_EVENT,
> @@ -165,6 +175,19 @@ static int perf_event__synthesize_one_bpf_prog(struct perf_tool *tool,
> memcpy(bpf_event->tag, info->tag, BPF_TAG_SIZE);
> memset((void *)event + event->header.size, 0, machine->id_hdr_size);
> event->header.size += machine->id_hdr_size;
> +
> + /* save bpf_prog_info to env */
> + info_node = malloc(sizeof(struct bpf_prog_info_node));
> + if (info_node) {
> + info_node->info_linear = info_linear;
> + perf_env__insert_bpf_prog_info(env, info_node);
> + info_linear = NULL;
> + }
> +
> + /*
> + * process after saving bpf_prog_info to env, so that
> + * required information is ready for look up
> + */
> err = perf_tool__process_synth_event(tool, event,
> machine, process);
> }
> @@ -175,7 +198,7 @@ static int perf_event__synthesize_one_bpf_prog(struct perf_tool *tool,
> return err ? -1 : 0;
> }
>
> -int perf_event__synthesize_bpf_events(struct perf_tool *tool,
> +int perf_event__synthesize_bpf_events(struct perf_session *session,
> perf_event__handler_t process,
> struct machine *machine,
> struct record_opts *opts)
> @@ -209,7 +232,7 @@ int perf_event__synthesize_bpf_events(struct perf_tool *tool,
> continue;
> }
>
> - err = perf_event__synthesize_one_bpf_prog(tool, process,
> + err = perf_event__synthesize_one_bpf_prog(session, process,
> machine, fd,
> event, opts);
> close(fd);
> diff --git a/tools/perf/util/bpf-event.h b/tools/perf/util/bpf-event.h
> index 7890067e1a37..11e6730b6105 100644
> --- a/tools/perf/util/bpf-event.h
> +++ b/tools/perf/util/bpf-event.h
> @@ -3,19 +3,28 @@
> #define __PERF_BPF_EVENT_H
>
> #include <linux/compiler.h>
> +#include <bpf/bpf.h>
> +#include <bpf/btf.h>
> +#include <bpf/libbpf.h>
> +#include <linux/btf.h>

Are you sure you'll need all of these headers here? Perhaps just some
forward declarations will do?

In fact the only bpf or btf structure here seems to be
bpf_prog_info_linear, which needs ust a forward declaration.

Avoiding these includes reduces the build time, and since the build-test
target does many builds and I want to build this in many containers, we
should try to reduce the build time by using just what is needed in each
header and C file. Also during development it helps with not rebuilding
tons of things when something unrelated changes in a header, etc.

- Arnaldo

> +#include <linux/rbtree.h>
> #include "event.h"
>
> struct machine;
> union perf_event;
> struct perf_sample;
> -struct perf_tool;
> struct record_opts;
>
> +struct bpf_prog_info_node {
> + struct bpf_prog_info_linear *info_linear;
> + struct rb_node rb_node;
> +};
> +
> #ifdef HAVE_LIBBPF_SUPPORT
> int machine__process_bpf_event(struct machine *machine, union perf_event *event,
> struct perf_sample *sample);
>
> -int perf_event__synthesize_bpf_events(struct perf_tool *tool,
> +int perf_event__synthesize_bpf_events(struct perf_session *session,
> perf_event__handler_t process,
> struct machine *machine,
> struct record_opts *opts);
> @@ -27,7 +36,7 @@ static inline int machine__process_bpf_event(struct machine *machine __maybe_unu
> return 0;
> }
>
> -static inline int perf_event__synthesize_bpf_events(struct perf_tool *tool __maybe_unused,
> +static inline int perf_event__synthesize_bpf_events(struct perf_session *session __maybe_unused,
> perf_event__handler_t process __maybe_unused,
> struct machine *machine __maybe_unused,
> struct record_opts *opts __maybe_unused)
> diff --git a/tools/perf/util/env.c b/tools/perf/util/env.c
> index 4c23779e271a..665b6fe3c7b2 100644
> --- a/tools/perf/util/env.c
> +++ b/tools/perf/util/env.c
> @@ -8,10 +8,86 @@
>
> struct perf_env perf_env;
>
> +void perf_env__insert_bpf_prog_info(struct perf_env *env,
> + struct bpf_prog_info_node *info_node)
> +{
> + __u32 prog_id = info_node->info_linear->info.id;
> + struct bpf_prog_info_node *node;
> + struct rb_node *parent = NULL;
> + struct rb_node **p;
> +
> + down_write(&env->bpf_info_lock);
> + p = &env->bpf_prog_infos.rb_node;
> +
> + while (*p != NULL) {
> + parent = *p;
> + node = rb_entry(parent, struct bpf_prog_info_node, rb_node);
> + if (prog_id < node->info_linear->info.id) {
> + p = &(*p)->rb_left;
> + } else if (prog_id > node->info_linear->info.id) {
> + p = &(*p)->rb_right;
> + } else {
> + pr_debug("duplicated bpf prog info %u\n", prog_id);
> + up_write(&env->bpf_info_lock);
> + return;
> + }
> + }
> +
> + rb_link_node(&info_node->rb_node, parent, p);
> + rb_insert_color(&info_node->rb_node, &env->bpf_prog_infos);
> + up_write(&env->bpf_info_lock);
> +}
> +
> +struct bpf_prog_info_node *perf_env__find_bpf_prog_info(struct perf_env *env,
> + __u32 prog_id)
> +{
> + struct bpf_prog_info_node *node = NULL;
> + struct rb_node *n;
> +
> + down_read(&env->bpf_info_lock);
> + n = env->bpf_prog_infos.rb_node;
> +
> + while (n) {
> + node = rb_entry(n, struct bpf_prog_info_node, rb_node);
> + if (prog_id < node->info_linear->info.id)
> + n = n->rb_left;
> + else if (prog_id > node->info_linear->info.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)
> +{
> + struct rb_root *root;
> + struct rb_node *next;
> +
> + down_write(&env->bpf_info_lock);
> +
> + root = &env->bpf_prog_infos;
> + next = rb_first(root);
> +
> + while (next) {
> + struct bpf_prog_info_node *node;
> +
> + node = rb_entry(next, struct bpf_prog_info_node, rb_node);
> + next = rb_next(&node->rb_node);
> + rb_erase_init(&node->rb_node, root);
> + free(node);
> + }
> + up_write(&env->bpf_info_lock);
> +}
> +
> void perf_env__exit(struct perf_env *env)
> {
> int i;
>
> + purge_bpf_info(env);
> zfree(&env->hostname);
> zfree(&env->os_release);
> zfree(&env->version);
> @@ -38,6 +114,12 @@ void perf_env__exit(struct perf_env *env)
> zfree(&env->memory_nodes);
> }
>
> +static void init_bpf_rb_trees(struct perf_env *env)
> +{
> + env->bpf_prog_infos = RB_ROOT;
> + init_rwsem(&env->bpf_info_lock);
> +}
> +
> int perf_env__set_cmdline(struct perf_env *env, int argc, const char *argv[])
> {
> int i;
> @@ -59,6 +141,7 @@ int perf_env__set_cmdline(struct perf_env *env, int argc, const char *argv[])
>
> env->nr_cmdline = argc;
>
> + init_bpf_rb_trees(env);
> return 0;
> out_free:
> zfree(&env->cmdline_argv);
> diff --git a/tools/perf/util/env.h b/tools/perf/util/env.h
> index d01b8355f4ca..a6d25e91bc98 100644
> --- a/tools/perf/util/env.h
> +++ b/tools/perf/util/env.h
> @@ -3,7 +3,10 @@
> #define __PERF_ENV_H
>
> #include <linux/types.h>
> +#include <linux/rbtree.h>
> #include "cpumap.h"
> +#include "rwsem.h"

You don't need the following header, just use a forward declaration for
the sole struct you use with a pointer:

struct bpf_prog_info_node;

> +#include "bpf-event.h"
>
> struct cpu_topology_map {
> int socket_id;
> @@ -64,6 +67,13 @@ struct perf_env {
> struct memory_node *memory_nodes;
> unsigned long long memory_bsize;
> u64 clockid_res_ns;
> +
> + /*
> + * bpf_info_lock protects bpf rbtrees. This is needed because the
> + * trees are accessed by different threads in perf-top
> + */
> + struct rw_semaphore bpf_info_lock;
> + struct rb_root bpf_prog_infos;

Please group this into a structure, i.e.:

struct {
struct rw_semaphore lock;
struct rb_root infos;
} bpf_progs;

> };
>
> extern struct perf_env perf_env;
> @@ -80,4 +90,8 @@ const char *perf_env__arch(struct perf_env *env);
> const char *perf_env__raw_arch(struct perf_env *env);
> int perf_env__nr_cpus_avail(struct perf_env *env);
>
> +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);
> #endif /* __PERF_ENV_H */
> --
> 2.17.1

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