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Date:   Thu,  2 Nov 2023 10:56:51 -0700
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Subject: [PATCH v4 09/53] perf maps: Switch modules tree walk to io_dir__readdir
From:   Ian Rogers <irogers@google.com>
To:     Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        Ian Rogers <irogers@google.com>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Nick Terrell <terrelln@fb.com>,
        Kan Liang <kan.liang@linux.intel.com>,
        Andi Kleen <ak@linux.intel.com>,
        Kajol Jain <kjain@linux.ibm.com>,
        Athira Rajeev <atrajeev@linux.vnet.ibm.com>,
        Huacai Chen <chenhuacai@kernel.org>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Vincent Whitchurch <vincent.whitchurch@axis.com>,
        "Steinar H. Gunderson" <sesse@google.com>,
        Liam Howlett <liam.howlett@oracle.com>,
        Miguel Ojeda <ojeda@kernel.org>,
        Colin Ian King <colin.i.king@gmail.com>,
        Dmitrii Dolgov <9erthalion6@gmail.com>,
        Yang Jihong <yangjihong1@huawei.com>,
        Ming Wang <wangming01@loongson.cn>,
        James Clark <james.clark@arm.com>,
        K Prateek Nayak <kprateek.nayak@amd.com>,
        Sean Christopherson <seanjc@google.com>,
        Leo Yan <leo.yan@linaro.org>,
        Ravi Bangoria <ravi.bangoria@amd.com>,
        German Gomez <german.gomez@arm.com>,
        Changbin Du <changbin.du@huawei.com>,
        Paolo Bonzini <pbonzini@redhat.com>, Li Dong <lidong@vivo.com>,
        Sandipan Das <sandipan.das@amd.com>,
        liuwenyu <liuwenyu7@huawei.com>, linux-kernel@vger.kernel.org,
        linux-perf-users@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Compared to glibc's opendir/readdir this lowers the max RSS of perf
record by 1.8MB on a Debian machine.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/util/machine.c | 19 ++++++++-----------
 1 file changed, 8 insertions(+), 11 deletions(-)

diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index a985d004aa8d..be3dab9d5253 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -36,6 +36,7 @@
 #include <internal/lib.h> // page_size
 #include "cgroup.h"
 #include "arm64-frame-pointer-unwind-support.h"
+#include <api/io_dir.h>
 
 #include <linux/ctype.h>
 #include <symbol/kallsyms.h>
@@ -1552,25 +1553,21 @@ static int maps__set_module_path(struct maps *maps, const char *path, struct kmo
 
 static int maps__set_modules_path_dir(struct maps *maps, const char *dir_name, int depth)
 {
-	struct dirent *dent;
-	DIR *dir = opendir(dir_name);
+	struct io_dirent64 *dent;
+	struct io_dir iod;
 	int ret = 0;
 
-	if (!dir) {
+	io_dir__init(&iod, open(dir_name, O_CLOEXEC | O_DIRECTORY | O_RDONLY));
+	if (iod.dirfd < 0) {
 		pr_debug("%s: cannot open %s dir\n", __func__, dir_name);
 		return -1;
 	}
 
-	while ((dent = readdir(dir)) != NULL) {
+	while ((dent = io_dir__readdir(&iod)) != NULL) {
 		char path[PATH_MAX];
-		struct stat st;
 
-		/*sshfs might return bad dent->d_type, so we have to stat*/
 		path__join(path, sizeof(path), dir_name, dent->d_name);
-		if (stat(path, &st))
-			continue;
-
-		if (S_ISDIR(st.st_mode)) {
+		if (io_dir__is_dir(&iod, dent)) {
 			if (!strcmp(dent->d_name, ".") ||
 			    !strcmp(dent->d_name, ".."))
 				continue;
@@ -1603,7 +1600,7 @@ static int maps__set_modules_path_dir(struct maps *maps, const char *dir_name, i
 	}
 
 out:
-	closedir(dir);
+	close(iod.dirfd);
 	return ret;
 }
 
-- 
2.42.0.869.gea05f2083d-goog