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 170AEC7EE24 for ; Fri, 2 Jun 2023 05:46:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233439AbjFBFqa (ORCPT ); Fri, 2 Jun 2023 01:46:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57454 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232144AbjFBFq0 (ORCPT ); Fri, 2 Jun 2023 01:46:26 -0400 X-Greylist: delayed 123 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Thu, 01 Jun 2023 22:46:20 PDT Received: from mx6.didiglobal.com (mx6.didiglobal.com [111.202.70.123]) by lindbergh.monkeyblade.net (Postfix) with SMTP id 8C4A4197 for ; Thu, 1 Jun 2023 22:46:19 -0700 (PDT) Received: from mail.didiglobal.com (unknown [10.79.65.12]) by mx6.didiglobal.com (Maildata Gateway V2.8) with ESMTPS id C8862110020826; Fri, 2 Jun 2023 13:44:14 +0800 (CST) Received: from didi-ThinkCentre-M930t-N000 (10.79.64.101) by ZJY02-ACTMBX-02.didichuxing.com (10.79.65.12) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.21; Fri, 2 Jun 2023 13:44:14 +0800 Date: Fri, 2 Jun 2023 13:44:04 +0800 X-MD-Sfrom: tiozhang@didiglobal.com X-MD-SrcIP: 10.79.65.12 From: Tio Zhang To: , , CC: , , , , , , , , Subject: [PATCH v3 2/2] sched: print parent comm in sched_show_task() Message-ID: <20230602054404.GA30014@didi-ThinkCentre-M930t-N000> Mail-Followup-To: pmladek@suse.com, yu.c.chen@intel.com, akpm@linux-foundation.org, juri.lelli@redhat.com, mingo@redhat.com, peterz@infradead.org, vincent.guittot@linaro.org, linux-kernel@vger.kernel.org, zyhtheonly@gmail.com, zwp10758@gmail.com, zyhtheonly@yeah.net MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) X-Originating-IP: [10.79.64.101] X-ClientProxiedBy: ZJY03-PUBMBX-01.didichuxing.com (10.79.71.12) To ZJY02-ACTMBX-02.didichuxing.com (10.79.65.12) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Knowing who the parent is might be useful for debugging. For example, we can sometimes resolve kernel hung tasks by stopping the person who begins those hung tasks. With the parent's name printed in sched_show_task(), it might be helpful to let people know which "service" should be operated. Also, we move the parent info to a following new line. It would be better to solve the situation when the task is not alive and we could not get information about the parent. Signed-off-by: Tio Zhang --- kernel/sched/core.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index cb2aa2b54c7a..d8fd35684d6c 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -8853,7 +8853,6 @@ SYSCALL_DEFINE2(sched_rr_get_interval_time32, pid_t, pid, void sched_show_task(struct task_struct *p) { unsigned long free = 0; - int ppid; if (!try_get_task_stack(p)) return; @@ -8865,14 +8864,19 @@ void sched_show_task(struct task_struct *p) #ifdef CONFIG_DEBUG_STACK_USAGE free = stack_not_used(p); #endif - ppid = 0; + + pr_cont(" stack:%-5lu pid:%-5d flags:0x%08lx\n", + free, task_pid_nr(p), read_task_thread_flags(p)); + rcu_read_lock(); - if (pid_alive(p)) - ppid = task_pid_nr(rcu_dereference(p->real_parent)); + if (pid_alive(p)) { + struct task_struct *parent = rcu_dereference(p->real_parent); + + pr_info("parent:%-15.15s ppid:%-6d\n", parent->comm, task_pid_nr(parent)); + } else { + pr_info("parent:unknown ppid:\n"); + } rcu_read_unlock(); - pr_cont(" stack:%-5lu pid:%-5d ppid:%-6d flags:0x%08lx\n", - free, task_pid_nr(p), ppid, - read_task_thread_flags(p)); print_worker_info(KERN_INFO, p); print_stop_info(KERN_INFO, p); -- 2.17.1