From mboxrd@z Thu Jan 1 00:00:00 1970 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 C4EABC4167D for ; Thu, 2 Nov 2023 17:58:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345946AbjKBR62 (ORCPT ); Thu, 2 Nov 2023 13:58:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43696 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345416AbjKBR6P (ORCPT ); Thu, 2 Nov 2023 13:58:15 -0400 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 17222D41 for ; Thu, 2 Nov 2023 10:58:08 -0700 (PDT) Received: by mail-yw1-x114a.google.com with SMTP id 00721157ae682-5a9012ab0adso16607047b3.1 for ; Thu, 02 Nov 2023 10:58:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1698947887; x=1699552687; 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=a6Vci0mC9udGUYdKEDx73CiSn3PyEtlzA+5ahyQMAZ4=; b=qWsvgZeRlRNWXJmobuMA8ozRIqJP5yfEypLT/BvgSn4T4NLhuMnAH1u1wCgCXM722X NMFw7a6XOMHAofd5D3VU2fCG27fU/cPn99EnI6O1svwyYtkknBWj8egFQ1ohOh3DBGLQ qDaZryoM4893mfcOThNNrx4R7/SlJ0cIwju7giWiIMBXCk8a+ldBX3/8lpDUz3F6l3qJ 1bLsVQ6A3csxVGnkJYvMak6oMYg4JQAd8PvUefJPv1aE90k6gBeMC8O/PfRoj1fKsYE4 UiWp6DBHczlVOeR+P1FVBikMv0NsYmWc61PlPbs3R7ZCG75fBJYHvxmoh8PO0lkARUKA bG3A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1698947887; x=1699552687; 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=a6Vci0mC9udGUYdKEDx73CiSn3PyEtlzA+5ahyQMAZ4=; b=t1QDKPT3H68FzMes6nUMo1MKayTtUywL9rtQODZVtQwJX5m03xiVox3wnglanSIKEe INlO37ZT2IxNP/iQordCgGQmKA/sH1fegKo35gVI+91EFXO6HDO/qMbUUULF90nk+o5K 9BJuEiaxYfdWx1gnWIAvNqBfEeWi8838Oh44wx9WUYqZGH3ivTuDxHZnjMsdSixVKgBi wbZBagKE19cETLn3rLChrzAVNhMFHZO34tDJ2SOfh0+ja+UHq2VWvfQglck0HZRmshJ9 ugxjT1BrlkCjayHatOLsRumaPoBvLi2HcDwkhY0UmoVgu3ySZ1c5BsN52ywZ84LkMmuA 1bUg== X-Gm-Message-State: AOJu0Yyhh6qazMrAdjWz2JXmt5oSmyxaK7Ei0lj6j01K9Rjabf+73v4t z6oFiAYJww3B3gOcb+a3Qa5VA54ze2uE X-Google-Smtp-Source: AGHT+IFVdxlw91qP8b57kxnW7/nVzbvdP5yIx9wN+HMQM3fYfY2qMWgHg8UxgNlfq9Phz416ozPUqLY5wTsM X-Received: from irogers.svl.corp.google.com ([2620:15c:2a3:200:bb34:df9c:836c:afca]) (user=irogers job=sendgmr) by 2002:a81:4855:0:b0:592:83d2:1f86 with SMTP id v82-20020a814855000000b0059283d21f86mr8582ywa.4.1698947887136; Thu, 02 Nov 2023 10:58:07 -0700 (PDT) Date: Thu, 2 Nov 2023 10:56:47 -0700 In-Reply-To: <20231102175735.2272696-1-irogers@google.com> Message-Id: <20231102175735.2272696-6-irogers@google.com> Mime-Version: 1.0 References: <20231102175735.2272696-1-irogers@google.com> X-Mailer: git-send-email 2.42.0.869.gea05f2083d-goog Subject: [PATCH v4 05/53] perf machine thread: Remove exited threads by default 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 Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org struct thread values hold onto references to mmaps, dsos, etc. When a thread exits it is necessary to clean all of this memory up by removing the thread from the machine's threads. Some tools require this doesn't happen, such as auxtrace events, perf report if offcpu events exist or if a task list is being generated, so add a symbol_conf value to make the behavior optional. When an exited thread is left in the machine's threads, mark it as exited. This change relates to commit 40826c45eb0b ("perf thread: Remove notion of dead threads"). Dead threads were removed as they had a reference count of 0 and were difficult to reason about with the reference count checker. Here a thread is removed from threads when it exits, unless via symbol_conf the exited thread isn't remove and is marked as exited. Reference counting behaves as it normally does. Signed-off-by: Ian Rogers --- tools/perf/builtin-report.c | 7 +++++++ tools/perf/util/machine.c | 10 +++++++--- tools/perf/util/session.c | 5 +++++ tools/perf/util/symbol_conf.h | 3 ++- tools/perf/util/thread.h | 14 ++++++++++++++ 5 files changed, 35 insertions(+), 4 deletions(-) diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c index 9cb1da2dc0c0..121a2781323c 100644 --- a/tools/perf/builtin-report.c +++ b/tools/perf/builtin-report.c @@ -1426,6 +1426,13 @@ int cmd_report(int argc, const char **argv) if (ret < 0) goto exit; + /* + * tasks_mode require access to exited threads to list those that are in + * the data file. Off-cpu events are synthesized after other events and + * reference exited threads. + */ + symbol_conf.keep_exited_threads = true; + annotation_options__init(&report.annotation_opts); ret = perf_config(report__config, &report); diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c index 90c750150b19..a985d004aa8d 100644 --- a/tools/perf/util/machine.c +++ b/tools/perf/util/machine.c @@ -2157,9 +2157,13 @@ int machine__process_exit_event(struct machine *machine, union perf_event *event if (dump_trace) perf_event__fprintf_task(event, stdout); - if (thread != NULL) - thread__put(thread); - + if (thread != NULL) { + if (symbol_conf.keep_exited_threads) + thread__set_exited(thread, /*exited=*/true); + else + machine__remove_thread(machine, thread); + } + thread__put(thread); return 0; } diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c index 1e9aa8ed15b6..c6afba7ab1a5 100644 --- a/tools/perf/util/session.c +++ b/tools/perf/util/session.c @@ -115,6 +115,11 @@ static int perf_session__open(struct perf_session *session, int repipe_fd) return -1; } + if (perf_header__has_feat(&session->header, HEADER_AUXTRACE)) { + /* Auxiliary events may reference exited threads, hold onto dead ones. */ + symbol_conf.keep_exited_threads = true; + } + if (perf_data__is_pipe(data)) return 0; diff --git a/tools/perf/util/symbol_conf.h b/tools/perf/util/symbol_conf.h index 2b2fb9e224b0..6040286e07a6 100644 --- a/tools/perf/util/symbol_conf.h +++ b/tools/perf/util/symbol_conf.h @@ -43,7 +43,8 @@ struct symbol_conf { disable_add2line_warn, buildid_mmap2, guest_code, - lazy_load_kernel_maps; + lazy_load_kernel_maps, + keep_exited_threads; const char *vmlinux_name, *kallsyms_name, *source_prefix, diff --git a/tools/perf/util/thread.h b/tools/perf/util/thread.h index e79225a0ea46..0df775b5c110 100644 --- a/tools/perf/util/thread.h +++ b/tools/perf/util/thread.h @@ -36,13 +36,22 @@ struct thread_rb_node { }; DECLARE_RC_STRUCT(thread) { + /** @maps: mmaps associated with this thread. */ struct maps *maps; pid_t pid_; /* Not all tools update this */ + /** @tid: thread ID number unique to a machine. */ pid_t tid; + /** @ppid: parent process of the process this thread belongs to. */ pid_t ppid; int cpu; int guest_cpu; /* For QEMU thread */ refcount_t refcnt; + /** + * @exited: Has the thread had an exit event. Such threads are usually + * removed from the machine's threads but some events/tools require + * access to dead threads. + */ + bool exited; bool comm_set; int comm_len; struct list_head namespaces_list; @@ -189,6 +198,11 @@ static inline refcount_t *thread__refcnt(struct thread *thread) return &RC_CHK_ACCESS(thread)->refcnt; } +static inline void thread__set_exited(struct thread *thread, bool exited) +{ + RC_CHK_ACCESS(thread)->exited = exited; +} + static inline bool thread__comm_set(const struct thread *thread) { return RC_CHK_ACCESS(thread)->comm_set; -- 2.42.0.869.gea05f2083d-goog