Date:   Fri, 15 Feb 2019 17:04:14 +0000
From:   Song Liu <songliubraving@...com>
To:     Arnaldo Carvalho de Melo <acme@...hat.com>
CC:     Netdev <netdev@...r.kernel.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        "ast@...nel.org" <ast@...nel.org>,
        "daniel@...earbox.net" <daniel@...earbox.net>,
        Kernel Team <Kernel-team@...com>,
        "peterz@...radead.org" <peterz@...radead.org>,
        "jolsa@...nel.org" <jolsa@...nel.org>,
        "namhyung@...nel.org" <namhyung@...nel.org>
Subject: Re: [PATCH v2 perf,bpf 05/11] perf, bpf: save bpf_prog_info in a
 rbtree in perf_env



> On Feb 15, 2019, at 6:21 AM, Arnaldo Carvalho de Melo <acme@...hat.com> wrote:
> 
> 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@...com>
>> ---
>> 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.

I see. I will fix this in next version. 

> 
> - 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;

Will fix this in next version. 

> 
>> };
>> 
>> 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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