From patchwork Wed Aug 2 12:47:28 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ze Gao X-Patchwork-Id: 13338134 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 7B89FC00528 for ; Wed, 2 Aug 2023 12:49:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234871AbjHBMtw (ORCPT ); Wed, 2 Aug 2023 08:49:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41710 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234866AbjHBMtO (ORCPT ); Wed, 2 Aug 2023 08:49:14 -0400 Received: from mail-pl1-x62b.google.com (mail-pl1-x62b.google.com [IPv6:2607:f8b0:4864:20::62b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C2A4726B0; Wed, 2 Aug 2023 05:49:08 -0700 (PDT) Received: by mail-pl1-x62b.google.com with SMTP id d9443c01a7336-1bbd2761f1bso56941595ad.2; Wed, 02 Aug 2023 05:49:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1690980548; x=1691585348; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=g/qteU2mNw/BBJfHNte7O9hoGmnD/YD+enA+yhOHga4=; b=OP/jxunnVEjIALdrKgklqzA4TO2+S7yZyoB1vbzcHPo2X6iSraTju6MNy/9+cLsb0I taQTHYoyq2w90sy33wYlAJ3mIV/itOpiNrHrs8ni5c/sxk9SwynCw+cMAkmx5/3XaO23 uJSstfIzoSZPaoSyDGEbhJoGIP+LnCLdWcvbNVAOZHI77pnQhyMrAI1moxomYA2BNZJQ KEGFxlUuaUpR+ot+U0zWAn2nNBi4288T02gfxTbIZsiyQb8R2sqC4SkhLv4DoMzQKMLa 1Sr8TCBwWEMtoFHmJ1CJzneu/JOAvkXbjmm1+wpAelgMux60eLIaTMMqTgpF/hrXJDtV Zv0Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690980548; x=1691585348; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=g/qteU2mNw/BBJfHNte7O9hoGmnD/YD+enA+yhOHga4=; b=HuZjXGx9xMf6ygdAChCGhZOlf95spDLPOIU79YBTM7Mhj9o0TMnMT5jUWNXNQBJ8Ie 9c4cYOqXhddL82LgfYpaxJpk1MxQs4m0vG//pHpVsb91rV4FsXnA4eEIEvGTemgd1nQ2 +AMsTEQTBxaGp6IQQGGnUn29ykVea4e27DzrJqh9XfUSJL9HpHhdBaeKnQfffmggBRMX sNf4twc//qGt4tnBMeFAGFOX6RwLUV1fUOskAXA2kzAkS5KTEQi0GmDE7LrwM6Nh4DZI wMp8pZmlN4JEC5wrhYlTqTuIaEG2Mig0dgLuTyGCyXtHPk8b+0baDhgOgAUMN0/8uMRm KXGA== X-Gm-Message-State: ABy/qLYa2kc1JvUWi7QX4cMe9H+F6Ts99fr20agiuPtmiRNH64Huz4ti lvZIXTcR9W/EUS83BZI8Ri4= X-Google-Smtp-Source: APBJJlHA7AJrJkY/XmvFc7K43FnZWwxGk3ty+ElpOYp1l0MN4z7lr7JxaCvjQdtuVGYHvkLSxSWktQ== X-Received: by 2002:a17:902:dac4:b0:1b8:8dbd:e1a0 with SMTP id q4-20020a170902dac400b001b88dbde1a0mr18050733plx.13.1690980548101; Wed, 02 Aug 2023 05:49:08 -0700 (PDT) Received: from localhost.localdomain ([203.205.141.17]) by smtp.googlemail.com with ESMTPSA id x34-20020a17090a6c2500b00264044cca0fsm4811993pjj.1.2023.08.02.05.49.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 02 Aug 2023 05:49:07 -0700 (PDT) From: Ze Gao X-Google-Original-From: Ze Gao To: Adrian Hunter , Alexander Shishkin , Arnaldo Carvalho de Melo , Ian Rogers , Ingo Molnar , Jiri Olsa , Mark Rutland , Masami Hiramatsu , Namhyung Kim , Peter Zijlstra , Steven Rostedt Cc: linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-trace-devel@vger.kernel.org, Ze Gao Subject: [RFC PATCH v5 5/7] sched, tracing: add to report task state in symbolic chars Date: Wed, 2 Aug 2023 08:47:28 -0400 Message-ID: <20230802124840.335638-6-zegao@tencent.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230802124840.335638-1-zegao@tencent.com> References: <20230802124840.335638-1-zegao@tencent.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-trace-kernel@vger.kernel.org Internal representations of task state are likely to be changed or ordered, and reporting them to userspace without exporting them as part of API is basically wrong, which can easily break a userspace observability tool as kernel evolves. For example, perf suffers from this and still reports wrong states as of this writing. OTOH, some masqueraded states like TASK_REPORT_IDLE and TASK_REPORT_MAX are also reported inadvertently, which confuses things even more and most userspace tools do not even take them into consideration. So add a new variable in company with the old raw value to report task state in symbolic chars, which are self-explaining and no further translation is needed. Of course this does not break any userspace tool. Note for PREEMPT_ACTIVE, we introduce 'p' to report it and use the old conventions for the rest. Signed-off-by: Ze Gao Reviewed-by: Masami Hiramatsu (Google) Acked-by: Ian Rogers --- include/trace/events/sched.h | 44 ++++++++++++++++++++++-------------- 1 file changed, 27 insertions(+), 17 deletions(-) diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h index 7d34db20b2c6..1c7b94793495 100644 --- a/include/trace/events/sched.h +++ b/include/trace/events/sched.h @@ -6,6 +6,7 @@ #define _TRACE_SCHED_H #include +#include #include #include #include @@ -214,6 +215,27 @@ static inline int __trace_sched_switch_state(bool preempt, return state ? (1 << (state - 1)) : state; } + +static inline char __trace_sched_switch_state_char(bool preempt, + unsigned int prev_state, + struct task_struct *p) +{ + long state; + +#ifdef CONFIG_SCHED_DEBUG + BUG_ON(p != current); +#endif /* CONFIG_SCHED_DEBUG */ + + /* + * For PREEMPT_ACTIVE, we introduce 'p' to report it and use the old + * conventions for the rest. + */ + if (preempt) + return 'p'; + + state = __task_state_index(prev_state, p->exit_state); + return task_index_to_char(state); +} #endif /* CREATE_TRACE_POINTS */ /* @@ -236,6 +258,7 @@ TRACE_EVENT(sched_switch, __field( int, prev_state ) __array( char, prev_comm, TASK_COMM_LEN ) __array( char, next_comm, TASK_COMM_LEN ) + __field( char, prev_state_char ) ), TP_fast_assign( @@ -246,26 +269,13 @@ TRACE_EVENT(sched_switch, __entry->prev_state = __trace_sched_switch_state(preempt, prev_state, prev); memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN); memcpy(__entry->next_comm, next->comm, TASK_COMM_LEN); + __entry->prev_state_char = __trace_sched_switch_state_char(preempt, prev_state, prev); /* XXX SCHED_DEADLINE */ ), - TP_printk("prev_comm=%s prev_pid=%d prev_prio=%d prev_state=%s%s ==> next_comm=%s next_pid=%d next_prio=%d", - __entry->prev_comm, __entry->prev_pid, __entry->prev_prio, - - (__entry->prev_state & (TASK_REPORT_MAX - 1)) ? - __print_flags(__entry->prev_state & (TASK_REPORT_MAX - 1), "|", - { TASK_INTERRUPTIBLE, "S" }, - { TASK_UNINTERRUPTIBLE, "D" }, - { __TASK_STOPPED, "T" }, - { __TASK_TRACED, "t" }, - { EXIT_DEAD, "X" }, - { EXIT_ZOMBIE, "Z" }, - { TASK_PARKED, "P" }, - { TASK_DEAD, "I" }) : - "R", - - __entry->prev_state & TASK_REPORT_MAX ? "+" : "", - __entry->next_comm, __entry->next_pid, __entry->next_prio) + TP_printk("prev_comm=%s prev_pid=%d prev_prio=%d prev_state=%c ==> next_comm=%s next_pid=%d next_prio=%d", + __entry->prev_comm, __entry->prev_pid, __entry->prev_prio, __entry->prev_state_char, __entry->next_comm, + __entry->next_pid, __entry->next_prio) ); /*