Messages in this thread Patch in this message | | | Date | Mon, 27 Nov 2023 14:08:23 -0800 | Subject | [PATCH v5 11/50] perf events: Remove scandir in thread synthesis | From | Ian Rogers <> |
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This avoids scanddir reading the directory into memory that's allocated and instead allocates on the stack.
Signed-off-by: Ian Rogers <irogers@google.com> --- tools/perf/util/synthetic-events.c | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-)
diff --git a/tools/perf/util/synthetic-events.c b/tools/perf/util/synthetic-events.c index a0579c7d7b9e..7cc38f2a0e9e 100644 --- a/tools/perf/util/synthetic-events.c +++ b/tools/perf/util/synthetic-events.c @@ -38,6 +38,7 @@ #include <uapi/linux/mman.h> /* To get things like MAP_HUGETLB even on older libc headers */ #include <api/fs/fs.h> #include <api/io.h> +#include <api/io_dir.h> #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> @@ -751,10 +752,10 @@ static int __event__synthesize_thread(union perf_event *comm_event, bool needs_mmap, bool mmap_data) { char filename[PATH_MAX]; - struct dirent **dirent; + struct io_dir iod; + struct io_dirent64 *dent; pid_t tgid, ppid; int rc = 0; - int i, n; /* special case: only send one comm event using passed in pid */ if (!full) { @@ -786,16 +787,19 @@ static int __event__synthesize_thread(union perf_event *comm_event, snprintf(filename, sizeof(filename), "%s/proc/%d/task", machine->root_dir, pid); - n = scandir(filename, &dirent, filter_task, NULL); - if (n < 0) - return n; + io_dir__init(&iod, open(filename, O_CLOEXEC | O_DIRECTORY | O_RDONLY)); + if (iod.dirfd < 0) + return -1; - for (i = 0; i < n; i++) { + while ((dent = io_dir__readdir(&iod)) != NULL) { char *end; pid_t _pid; bool kernel_thread = false; - _pid = strtol(dirent[i]->d_name, &end, 10); + if (!isdigit(dent->d_name[0])) + continue; + + _pid = strtol(dent->d_name, &end, 10); if (*end) continue; @@ -829,9 +833,7 @@ static int __event__synthesize_thread(union perf_event *comm_event, } } - for (i = 0; i < n; i++) - zfree(&dirent[i]); - free(dirent); + close(iod.dirfd); return rc; } -- 2.43.0.rc1.413.gea7ed67945-goog
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