From patchwork Wed Jul 26 12:16:16 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ze Gao X-Patchwork-Id: 13327936 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 06C0FC001DE for ; Wed, 26 Jul 2023 12:16:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233030AbjGZMQg (ORCPT ); Wed, 26 Jul 2023 08:16:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32808 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232529AbjGZMQd (ORCPT ); Wed, 26 Jul 2023 08:16:33 -0400 Received: from mail-pj1-x1032.google.com (mail-pj1-x1032.google.com [IPv6:2607:f8b0:4864:20::1032]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E2B2F10F6; Wed, 26 Jul 2023 05:16:31 -0700 (PDT) Received: by mail-pj1-x1032.google.com with SMTP id 98e67ed59e1d1-268541d2947so285847a91.3; Wed, 26 Jul 2023 05:16:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1690373791; x=1690978591; 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=+7C0SBBUXP7O5XpijSeSyahi4TrgeBmdTgGvodmmzYM=; b=XzMmYD4oHTLISgh06EvMKIHnqyDaAepCtWmGauT3Qzqyb7kZLLWqYfYbB4Pm7yav9d je6i3VWhEw6JUGHj+xZR2N5681313IbwF2AMc/szvtVKYHys/kusZbo8o0Y42jGY/8rJ Momphh63sD5VKFa2RGMHrQWJVyhqP+tejBn5Ciet8SlRYk8LVWjk0MWa6nQXRaFJrs68 KPe+6J5dANx1jE+NccjEXdLgUKBlCyrfMYb/6Gy4n4sdhsfgJ5yiMxd29fFaO671ryeT N7O8pn2YOw0BNB1O3ZT5jR0b2VEFqVJHzxzg9+9PHrTEOws8ULVd7x5TmjMtxXNAqqfx g00g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690373791; x=1690978591; 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=+7C0SBBUXP7O5XpijSeSyahi4TrgeBmdTgGvodmmzYM=; b=iFdVTIvWPgVLYv++RKfW7uKonQIJjwKv7ja36vcsV57gvArqnV6r657rigULFvivCw 8EMeaM9pokIvBQeCMM5/iXnOSJI7ZqElwF+QatYA26V3wRAJLPKuQdxKTe1JtkDXSAQR 42IJKnwoch45o0zDxC8Ykk9qtaELTN33hl4KNd4YTThuZhidgnh1aUA62jB8r5Ke2qRY PO67CiZai37knZGQ90vEAfDsf0k5yvuQoI7Jg2c6MyDThC/iuKg06zUKMgOAoj/JXCli k6B5Pz4n08QPF0n6x5my0ht+scRYupOWrfZDwqDUVaMmDd1MnNtzAj6Ue6sgh26IQ07e yxNA== X-Gm-Message-State: ABy/qLYz+OkkXWiCvlw2/09ww/pGUYQqTSOjf8yrx1TGPYknC5Vm/F54 ogEZ486eJNgt+W6AbI3ReJI= X-Google-Smtp-Source: APBJJlFPvsWN5escZL4T61sXRxRP6pt3wd53DBOmWtJCu0YtL1ojSt6nONVrv047Sx2zgvhHDjVHYA== X-Received: by 2002:a17:90b:3b81:b0:263:f435:ef2d with SMTP id pc1-20020a17090b3b8100b00263f435ef2dmr1326501pjb.10.1690373791215; Wed, 26 Jul 2023 05:16:31 -0700 (PDT) Received: from localhost.localdomain ([203.205.141.25]) by smtp.googlemail.com with ESMTPSA id ms19-20020a17090b235300b00263f446d432sm1172880pjb.43.2023.07.26.05.16.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 26 Jul 2023 05:16:30 -0700 (PDT) From: Ze Gao X-Google-Original-From: Ze Gao To: Peter Zijlstra , Steven Rostedt , Namhyung Kim Cc: Adrian Hunter , Alexander Shishkin , Arnaldo Carvalho de Melo , Ian Rogers , Ingo Molnar , Jiri Olsa , Mark Rutland , Masami Hiramatsu , 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 v2 1/3] sched, tracing: add to report task state in symbolic chars Date: Wed, 26 Jul 2023 20:16:16 +0800 Message-Id: <20230726121618.19198-2-zegao@tencent.com> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230726121618.19198-1-zegao@tencent.com> References: <20230726121618.19198-1-zegao@tencent.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@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 not a good choice, which can easily break a userspace observability tool as kernel evolves. For example, perf suffers from this and still reports wrong states by this patch. OTOH, some masqueraded state like TASK_REPORT_IDLE and TASK_REPORT_MAX are also reported inadvertently, which confuses things even more. So add a new variable in company with the old raw value to report task state in symbolic char, which is self-explaining and no further translation is needed, and also report priorities in 'short' to save some buffer space. 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 --- include/trace/events/sched.h | 60 +++++++++++++++++++++--------------- 1 file changed, 35 insertions(+), 25 deletions(-) diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h index fbb99a61f714..0fcf68f49e45 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 long __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 */ /* @@ -231,41 +253,29 @@ TRACE_EVENT(sched_switch, TP_STRUCT__entry( __array( char, prev_comm, TASK_COMM_LEN ) __field( pid_t, prev_pid ) - __field( int, prev_prio ) - __field( long, prev_state ) + __field( short, prev_prio ) + __field( int, prev_state ) + __field( char, prev_state_char ) __array( char, next_comm, TASK_COMM_LEN ) __field( pid_t, next_pid ) - __field( int, next_prio ) + __field( short, next_prio ) ), TP_fast_assign( memcpy(__entry->next_comm, next->comm, TASK_COMM_LEN); - __entry->prev_pid = prev->pid; - __entry->prev_prio = prev->prio; - __entry->prev_state = __trace_sched_switch_state(preempt, prev_state, prev); + __entry->prev_pid = prev->pid; + __entry->prev_prio = (short) prev->prio; + __entry->prev_state = __trace_sched_switch_state(preempt, prev_state, prev); + __entry->prev_state_char = __trace_sched_switch_state_char(preempt, prev_state, prev); memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN); - __entry->next_pid = next->pid; - __entry->next_prio = next->prio; + __entry->next_pid = next->pid; + __entry->next_prio = (short) next->prio; /* 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) ); /*