From nobody Wed Dec 17 12:44:27 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 83849C4167B for ; Mon, 27 Nov 2023 22:10:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233846AbjK0WK0 (ORCPT ); Mon, 27 Nov 2023 17:10:26 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43984 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233571AbjK0WJ7 (ORCPT ); Mon, 27 Nov 2023 17:09:59 -0500 Received: from mail-yw1-x114a.google.com (mail-yw1-x114a.google.com [IPv6:2607:f8b0:4864:20::114a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 212FB1BD8 for ; Mon, 27 Nov 2023 14:09:50 -0800 (PST) Received: by mail-yw1-x114a.google.com with SMTP id 00721157ae682-5d04540d5aaso21623517b3.1 for ; Mon, 27 Nov 2023 14:09:50 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1701122989; x=1701727789; darn=vger.kernel.org; h=to:from:subject:references:mime-version:message-id:in-reply-to:date :from:to:cc:subject:date:message-id:reply-to; bh=jTXjNUPwbxQAEQgmTX6mZhuaXcNBEgojUyDX7h5oWL4=; b=gaFHynnwMcnRMOSKlWtWX99TjWcgrYlOUg5hj3kibRIit5u3rZHZtDBzwTcH3s44p1 jrcY2LS0XuLUCHUNBAmbtgCxfbujEW+egZh3E9Fm1eMtm9I4lBxGDtiSRDSrjvuoefiK vy5ZW4xMp/+E/XTK1N9NnnhjH72/Q/phwB1XvBOnO0MgLdX5Qp7pfdrfHG9GA5TA0JWK 6R8MSGNgJ79dxjcX8PSrSBPvl1WTjgxI38lBM/uaz0q2EEVK2/q4gbKcmuoWMHruPGvt LsolBCI0l9dxAGJrp3QShhQDfrEeeJ9y1MSnu+gtcwbScqhUvXCYjopNdAr9ym/jNPUc Vs+A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1701122989; x=1701727789; h=to:from:subject:references:mime-version:message-id:in-reply-to:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=jTXjNUPwbxQAEQgmTX6mZhuaXcNBEgojUyDX7h5oWL4=; b=gtPjW7OcqOvclJDYNmv+agL1yUmcwxRz4fnZhBcGAxMtyEWOdRIfhfJ/ozENs6k/2x 9r14U6PUHsaLsfCPlpxEHCeAlVHIxPfdKKt/HLNN53iOyYz5kHuh4RvaeGG4D+24K3iP CCLRck5/P9FyItOTzSZ1JC3yRz/ZgBQE3usBo1L46XjMbpZ3mt1aZyX9w6rrXDDQWsp4 whQsT+ACZ3J8A2HwlpjiryHbbbqWVCv73MFhVOeeYH93Uf8qKfhxHqaQIezvfNDZHR9c tlMz8A2AfDwCQKIwLv/HU8TjkU4v8FTSHOHlKam7idxnJPy7fq47OgxTZX+6ALHAv9WB vAzw== X-Gm-Message-State: AOJu0Yx7ElzNIn/FJcIG7PoytyrYuRd2Iol5HDJgunuNsYmO7R/bRtOO tMl8tKX93Rk1GZcioAZOCvaqg3goSJAD X-Google-Smtp-Source: AGHT+IFkUH1ezGScaVKIf2YW5rYtSWPzFdtRJ2PPO8tpyodcdiEAUOOg8jRQ1N1tVpIi1px37r7gN1f6wAY2 X-Received: from irogers.svl.corp.google.com ([2620:15c:2a3:200:829:6e77:9093:f39b]) (user=irogers job=sendgmr) by 2002:a81:be14:0:b0:5d0:a744:7194 with SMTP id i20-20020a81be14000000b005d0a7447194mr137899ywn.2.1701122989163; Mon, 27 Nov 2023 14:09:49 -0800 (PST) Date: Mon, 27 Nov 2023 14:08:23 -0800 In-Reply-To: <20231127220902.1315692-1-irogers@google.com> Message-Id: <20231127220902.1315692-12-irogers@google.com> Mime-Version: 1.0 References: <20231127220902.1315692-1-irogers@google.com> X-Mailer: git-send-email 2.43.0.rc1.413.gea7ed67945-goog Subject: [PATCH v5 11/50] perf events: Remove scandir in thread synthesis From: Ian Rogers To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Ian Rogers , Adrian Hunter , Nick Terrell , Kan Liang , Andi Kleen , Kajol Jain , Athira Rajeev , Huacai Chen , Masami Hiramatsu , Vincent Whitchurch , "Steinar H. Gunderson" , Liam Howlett , Miguel Ojeda , Colin Ian King , Dmitrii Dolgov <9erthalion6@gmail.com>, Yang Jihong , Ming Wang , James Clark , K Prateek Nayak , Sean Christopherson , Leo Yan , Ravi Bangoria , German Gomez , Changbin Du , Paolo Bonzini , Li Dong , Sandipan Das , liuwenyu , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Guilherme Amadio Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" This avoids scanddir reading the directory into memory that's allocated and instead allocates on the stack. Signed-off-by: Ian Rogers Acked-by: Namhyung Kim --- 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 /* To get things like MAP_HUGETLB even on old= er libc headers */ #include #include +#include #include #include #include @@ -751,10 +752,10 @@ static int __event__synthesize_thread(union perf_even= t *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 =3D 0; - int i, n; =20 /* special case: only send one comm event using passed in pid */ if (!full) { @@ -786,16 +787,19 @@ static int __event__synthesize_thread(union perf_even= t *comm_event, snprintf(filename, sizeof(filename), "%s/proc/%d/task", machine->root_dir, pid); =20 - n =3D 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; =20 - for (i =3D 0; i < n; i++) { + while ((dent =3D io_dir__readdir(&iod)) !=3D NULL) { char *end; pid_t _pid; bool kernel_thread =3D false; =20 - _pid =3D strtol(dirent[i]->d_name, &end, 10); + if (!isdigit(dent->d_name[0])) + continue; + + _pid =3D strtol(dent->d_name, &end, 10); if (*end) continue; =20 @@ -829,9 +833,7 @@ static int __event__synthesize_thread(union perf_event = *comm_event, } } =20 - for (i =3D 0; i < n; i++) - zfree(&dirent[i]); - free(dirent); + close(iod.dirfd); =20 return rc; } --=20 2.43.0.rc1.413.gea7ed67945-goog