From patchwork Thu Oct 21 03:46:02 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yafang Shao X-Patchwork-Id: 12573771 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0A79FC4332F for ; Thu, 21 Oct 2021 03:47:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E6DA661038 for ; Thu, 21 Oct 2021 03:47:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231799AbhJUDtt (ORCPT ); Wed, 20 Oct 2021 23:49:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34056 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231422AbhJUDtY (ORCPT ); Wed, 20 Oct 2021 23:49:24 -0400 Received: from mail-pl1-x62a.google.com (mail-pl1-x62a.google.com [IPv6:2607:f8b0:4864:20::62a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2DC8BC0613E6; Wed, 20 Oct 2021 20:46:17 -0700 (PDT) Received: by mail-pl1-x62a.google.com with SMTP id i1so958921plr.13; Wed, 20 Oct 2021 20:46:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=0yM3sBzVJixym6Pyyba7mfqYZoAEZb2k8KizyPSP7kg=; b=RBw5omD4rTgpJrDE/tF+65u3aiUUhbDOjoxYbOUTHLFsfzRCE1qLcza3dSQSuVNI9x yF4Rv2/3XR1+nsVOwkxJWIeuqgR8C3VcwQcCdU+q+hrFIAEEkfojFwHV5SSDlODMV7wD Mg5hYwDDJUQS44dzlc46KJxWu33Q+ADcSFvpUJBAomHNtUFnd8YHwF+ThysyEXXq9PJf BemE8OTfob3ebmojHzE0pKT/udvY799lkaP2MVbPwq7KVGJQ1w03aj0fSkmeod98u3Om gIH2TvQtYBYmddoWcGYRYg8zpNyFg0MTuSO4IRoDXuzXdLDJcsFbabi0At9po1agLjxj gNQQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=0yM3sBzVJixym6Pyyba7mfqYZoAEZb2k8KizyPSP7kg=; b=izgIHKy7yJ4Nzs6J5w9kzu8lnBFIax+A6dO3vMqwLXedzP690Fgin6hcmsvwFtZ218 +h5z/mK0N2+mgO8EWyEBf8HBi/1enSmUUY8q9RfAx6+B0sFtgg4AAepLGzobKYpIlXrU HrdksSQBJmOHOsqVQQc63DgEQ2o3BY5uq9KGl8p+ifusB4Ac7F+n13D7eIx0Cj8l3uMZ UnKb4xk37WeAaTBxEBmrmo011cjSlPW+WJHLF0IUoxbO2n5FH4ma4xcYpLwSqUSUldDm FMHKbxjkpziAZcOo75LDlWCPsNcLTR81f/w1FaAKGj2J9VMd85A9DU5Vwi6oTuC9HVEw YHTQ== X-Gm-Message-State: AOAM530qiLSdCq1ZM9ZMZMWa+SM1hVVb0jJU3INahcsSTNcZ+cISL/0x eraDNHWPG+4k3oTVUN2L/VE= X-Google-Smtp-Source: ABdhPJxUL9qjB7igAdeOyZKwIJlugL1A0condl4sE5mTHamDXIGLy5/Lf+hpbqa+DOy9OirQoWCv4A== X-Received: by 2002:a17:90a:2a0d:: with SMTP id i13mr3517622pjd.166.1634787976727; Wed, 20 Oct 2021 20:46:16 -0700 (PDT) Received: from localhost.localdomain ([140.82.17.67]) by smtp.gmail.com with ESMTPSA id r25sm3454254pge.61.2021.10.20.20.46.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 20 Oct 2021 20:46:16 -0700 (PDT) From: Yafang Shao To: keescook@chromium.org, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, arnaldo.melo@gmail.com, pmladek@suse.com, peterz@infradead.org, viro@zeniv.linux.org.uk, akpm@linux-foundation.org, valentin.schneider@arm.com, qiang.zhang@windriver.com, robdclark@chromium.org, christian@brauner.io, dietmar.eggemann@arm.com, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, davem@davemloft.net, kuba@kernel.org, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, kafai@fb.com, songliubraving@fb.com, yhs@fb.com, john.fastabend@gmail.com, kpsingh@kernel.org Cc: netdev@vger.kernel.org, bpf@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, oliver.sang@intel.com, lkp@intel.com, Yafang Shao Subject: [PATCH v5 14/15] sched.h: extend task comm from 16 to 24 for CONFIG_BASE_FULL Date: Thu, 21 Oct 2021 03:46:02 +0000 Message-Id: <20211021034603.4458-5-laoar.shao@gmail.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20211021034603.4458-1-laoar.shao@gmail.com> References: <20211021034603.4458-1-laoar.shao@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org When I was implementing a new per-cpu kthread cfs_migration, I found the comm of it "cfs_migration/%u" is truncated due to the limitation of TASK_COMM_LEN. For example, the comm of the percpu thread on CPU10~19 are all with the same name "cfs_migration/1", which will confuse the user. This issue is not critical, because we can get the corresponding CPU from the task's Cpus_allowed. But for kthreads correspoinding to other hardware devices, it is not easy to get the detailed device info from task comm, for example, jbd2/nvme0n1p2- xfs-reclaim/sdf We can also shorten the name to work around this problem, but I find there are so many truncated kthreads: rcu_tasks_kthre rcu_tasks_rude_ rcu_tasks_trace poll_mpt3sas0_s ext4-rsv-conver xfs-reclaim/sd{a, b, c, ...} xfs-blockgc/sd{a, b, c, ...} xfs-inodegc/sd{a, b, c, ...} audit_send_repl ecryptfs-kthrea vfio-irqfd-clea jbd2/nvme0n1p2- ... We should improve this problem fundamentally. This patch extends the size of task comm to 24 bytes, which is the same length with workqueue's, for the CONFIG_BASE_FULL case. And for the CONFIG_BASE_SMALL case, the size of task comm is still kept as 16 bytes. After this patchset, the truncated kthreads listed above will be displayed as: rcu_tasks_kthread rcu_tasks_rude_kthread rcu_tasks_trace_kthread poll_mpt3sas0_statu ext4-rsv-conversion xfs-reclaim/sdf1 xfs-blockgc/sdf1 xfs-inodegc/sdf1 audit_send_reply ecryptfs-kthread vfio-irqfd-cleanup jbd2/nvme0n1p2-8 Suggested-by: Petr Mladek Suggested-by: Steven Rostedt Signed-off-by: Yafang Shao Reviewed-by: Kees Cook Cc: Mathieu Desnoyers Cc: Arnaldo Carvalho de Melo Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Al Viro Cc: Petr Mladek --- include/linux/sched.h | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index 62d5b30d310c..fcb4bc97f95c 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -274,10 +274,17 @@ struct task_group; #define get_current_state() READ_ONCE(current->__state) -/* To replace the old hard-coded 16 */ -#define TASK_COMM_LEN_16 16 +/* Also to replace the old hard-coded 16 */ +#define TASK_COMM_LEN_16 16 +#define TASK_COMM_LEN_24 24 + + /* Task command name length: */ -#define TASK_COMM_LEN 16 +#if CONFIG_BASE_SMALL +#define TASK_COMM_LEN TASK_COMM_LEN_16 +#else +#define TASK_COMM_LEN TASK_COMM_LEN_24 +#endif extern void scheduler_tick(void);