From patchwork Wed Aug 2 12:10:00 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ze Gao X-Patchwork-Id: 13338085 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 CE05DC001DF for ; Wed, 2 Aug 2023 12:12:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234477AbjHBMMU (ORCPT ); Wed, 2 Aug 2023 08:12:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45236 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234485AbjHBMMF (ORCPT ); Wed, 2 Aug 2023 08:12:05 -0400 Received: from mail-pl1-x635.google.com (mail-pl1-x635.google.com [IPv6:2607:f8b0:4864:20::635]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 20D252D4E; Wed, 2 Aug 2023 05:11:46 -0700 (PDT) Received: by mail-pl1-x635.google.com with SMTP id d9443c01a7336-1b8ad356f03so42082075ad.1; Wed, 02 Aug 2023 05:11:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1690978305; x=1691583105; 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=4CM5cahXoMpsce0ksxrUnsFD5Y5C6ho7KAY2TXexFWA=; b=gdF734EWkU9OnMkBaivwtHzXYRbnETPo8fXWApDkqnoLjTTcWM52zjCepXhgLv60rX uu+x/g2BUXJVYS4AHV6VldapUIFlSNcOljFQqaMKw0OXopwyC+t07nuB2NQrQrUGwpKP 3Ba26I0T0zih86GAv8qkWRqlzQH+z8sFvK61LfO5j3JqTDt8klfrTPz+RU80nVnUffd0 QvRbFRRxg7LKp62u8xqpyHTG9b/hD8GX1fop07TZQfZggg8W0UQ4OSXBZgTQtolVFA4a gvHpGxkwcgKxiG1t5NU358WhWE3oGtkMSOGtPTdW28a7NrY5201jmIBcUIY5EcPC0OIn uBhA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690978305; x=1691583105; 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=4CM5cahXoMpsce0ksxrUnsFD5Y5C6ho7KAY2TXexFWA=; b=iUq0hEQel3C7sT+VaOqmJE39TWp2PJSD673kKWVgaeHS0rL2eTdLL2zPsWPK2q5Ku+ tcjgBtza12cpjwTvUhdGF5onTvUw2CrNMczhe8PvNsWmLoUkNdl+b/ESqXB++QHF5GUz 7ABJYY+fednX1tmq/cMqAo8SyuCAyYlGWzgFWwekBv6kxgKCvw9YGT91mjug1WQy5PK7 sOEt0gqQFpwY2iVIpTR22BDsFN1NhNTAQdID0MyJba9tl8PtBgqX/hFMhCtkEWbuBfjX Z3z8LwTkXyLQ/DwYKJsVnHbBwdS2LHZOsgXIal3ACQOJGIqvEZUumeu0jqh3Sw/QTMwi ravw== X-Gm-Message-State: ABy/qLYrdQpluuCYlUszfqmVRFX1eCqJb5QF47Ee85uF78wY042CmhPR QfN8ccNTK2KG7i7IScUnzP8= X-Google-Smtp-Source: APBJJlEVUkNyVhX5WkJf04Si93Ho7Ne7U3pFFbhVk7WPxbfjWoZHEDISUAcKgSu/O3EmWF5E3lRlAg== X-Received: by 2002:a17:903:1cb:b0:1b8:9044:9ede with SMTP id e11-20020a17090301cb00b001b890449edemr16848580plh.62.1690978305253; Wed, 02 Aug 2023 05:11:45 -0700 (PDT) Received: from localhost.localdomain ([43.132.98.115]) by smtp.googlemail.com with ESMTPSA id kx14-20020a170902f94e00b001b890009634sm12293173plb.139.2023.08.02.05.11.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 02 Aug 2023 05:11:44 -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 , Ze Gao Subject: [RFC PATCH v4 5/7] sched, tracing: add to report task state in symbolic chars Date: Wed, 2 Aug 2023 08:10:00 -0400 Message-ID: <20230802121116.324604-6-zegao@tencent.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230802121116.324604-1-zegao@tencent.com> References: <20230802121116.324604-1-zegao@tencent.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-trace-kernel@vger.kernel.org From: Ze Gao 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) ); /*