linux-kernel - [PATCH v2 6/7] perf parse-events: Switch tracepoints to io_dir_

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20250207232452.994822-7-irogers@google.com>
Date: Fri,  7 Feb 2025 15:24:47 -0800
From: Ian Rogers <irogers@...gle.com>
To: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>, 
	Arnaldo Carvalho de Melo <acme@...nel.org>, Namhyung Kim <namhyung@...nel.org>, 
	Mark Rutland <mark.rutland@....com>, 
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>, 
	Ian Rogers <irogers@...gle.com>, Adrian Hunter <adrian.hunter@...el.com>, 
	Kan Liang <kan.liang@...ux.intel.com>, Sam James <sam@...too.org>, 
	Jesper Juhl <jesperjuhl76@...il.com>, James Clark <james.clark@...aro.org>, 
	Zhongqiu Han <quic_zhonhan@...cinc.com>, Yicong Yang <yangyicong@...ilicon.com>, 
	Thomas Richter <tmricht@...ux.ibm.com>, Michael Petlan <mpetlan@...hat.com>, 
	Veronika Molnarova <vmolnaro@...hat.com>, Anne Macedo <retpolanne@...teo.net>, 
	Dominique Martinet <asmadeus@...ewreck.org>, 
	Jean-Philippe Romain <jean-philippe.romain@...s.st.com>, Junhao He <hejunhao3@...wei.com>, 
	linux-kernel@...r.kernel.org, linux-perf-users@...r.kernel.org, 
	"Krzysztof Łopatowski" <krzysztof.m.lopatowski@...il.com>
Subject: [PATCH v2 6/7] perf parse-events: Switch tracepoints to io_dir__readdir

Avoid DIR allocations when scanning sysfs by using io_dir for the
readdir implementation, that allocates about 1kb on the stack.

Signed-off-by: Ian Rogers <irogers@...gle.com>
---
 tools/lib/api/io_dir.h         |  2 --
 tools/perf/util/parse-events.c | 32 +++++++++++++++++++-------------
 2 files changed, 19 insertions(+), 15 deletions(-)

diff --git a/tools/lib/api/io_dir.h b/tools/lib/api/io_dir.h
index c84738923c96..9f07460afacc 100644
--- a/tools/lib/api/io_dir.h
+++ b/tools/lib/api/io_dir.h
@@ -89,5 +89,3 @@ static inline bool io_dir__is_dir(const struct io_dir *iod, struct io_dirent64 *
 	}
 	return dent->d_type == DT_DIR;
 }
-
-#endif
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 6c36b98875bc..35e48fe56dfa 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -17,6 +17,7 @@
 #include "strbuf.h"
 #include "debug.h"
 #include <api/fs/tracing_path.h>
+#include <api/io_dir.h>
 #include <perf/cpumap.h>
 #include <util/parse-events-bison.h>
 #include <util/parse-events-flex.h>
@@ -554,8 +555,8 @@ static int add_tracepoint_multi_event(struct parse_events_state *parse_state,
 				      struct parse_events_terms *head_config, YYLTYPE *loc)
 {
 	char *evt_path;
-	struct dirent *evt_ent;
-	DIR *evt_dir;
+	struct io_dirent64 *evt_ent;
+	struct io_dir evt_dir;
 	int ret = 0, found = 0;
 
 	evt_path = get_events_file(sys_name);
@@ -563,14 +564,14 @@ static int add_tracepoint_multi_event(struct parse_events_state *parse_state,
 		tracepoint_error(err, errno, sys_name, evt_name, loc->first_column);
 		return -1;
 	}
-	evt_dir = opendir(evt_path);
-	if (!evt_dir) {
+	io_dir__init(&evt_dir, open(evt_path, O_CLOEXEC | O_DIRECTORY | O_RDONLY));
+	if (evt_dir.dirfd < 0) {
 		put_events_file(evt_path);
 		tracepoint_error(err, errno, sys_name, evt_name, loc->first_column);
 		return -1;
 	}
 
-	while (!ret && (evt_ent = readdir(evt_dir))) {
+	while (!ret && (evt_ent = io_dir__readdir(&evt_dir))) {
 		if (!strcmp(evt_ent->d_name, ".")
 		    || !strcmp(evt_ent->d_name, "..")
 		    || !strcmp(evt_ent->d_name, "enable")
@@ -592,7 +593,7 @@ static int add_tracepoint_multi_event(struct parse_events_state *parse_state,
 	}
 
 	put_events_file(evt_path);
-	closedir(evt_dir);
+	close(evt_dir.dirfd);
 	return ret;
 }
 
@@ -615,17 +616,23 @@ static int add_tracepoint_multi_sys(struct parse_events_state *parse_state,
 				    struct parse_events_error *err,
 				    struct parse_events_terms *head_config, YYLTYPE *loc)
 {
-	struct dirent *events_ent;
-	DIR *events_dir;
+	struct io_dirent64 *events_ent;
+	struct io_dir events_dir;
 	int ret = 0;
+	char *events_dir_path = get_tracing_file("events");
 
-	events_dir = tracing_events__opendir();
-	if (!events_dir) {
+	if (!events_dir_path) {
+		tracepoint_error(err, errno, sys_name, evt_name, loc->first_column);
+		return -1;
+	}
+	io_dir__init(&events_dir, open(events_dir_path, O_CLOEXEC | O_DIRECTORY | O_RDONLY));
+	put_events_file(events_dir_path);
+	if (events_dir.dirfd < 0) {
 		tracepoint_error(err, errno, sys_name, evt_name, loc->first_column);
 		return -1;
 	}
 
-	while (!ret && (events_ent = readdir(events_dir))) {
+	while (!ret && (events_ent = io_dir__readdir(&events_dir))) {
 		if (!strcmp(events_ent->d_name, ".")
 		    || !strcmp(events_ent->d_name, "..")
 		    || !strcmp(events_ent->d_name, "enable")
@@ -639,8 +646,7 @@ static int add_tracepoint_multi_sys(struct parse_events_state *parse_state,
 		ret = add_tracepoint_event(parse_state, list, events_ent->d_name,
 					   evt_name, err, head_config, loc);
 	}
-
-	closedir(events_dir);
+	close(events_dir.dirfd);
 	return ret;
 }
 
-- 
2.48.1.502.g6dc24dfdaf-goog