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 X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B8DEAC4CEC9 for ; Wed, 18 Sep 2019 01:25:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8808620578 for ; Wed, 18 Sep 2019 01:25:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="qOFgBadN" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728596AbfIRBZw (ORCPT ); Tue, 17 Sep 2019 21:25:52 -0400 Received: from mail-pf1-f194.google.com ([209.85.210.194]:35507 "EHLO mail-pf1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727354AbfIRBZw (ORCPT ); Tue, 17 Sep 2019 21:25:52 -0400 Received: by mail-pf1-f194.google.com with SMTP id 205so3268895pfw.2 for ; Tue, 17 Sep 2019 18:25:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=qTucIh8q1fOUaY+KKBj6aQtvZjzoQVm4j1aVcrELJdg=; b=qOFgBadN95TeEZ2PDXgkMFaZWHVt7J+pDCghlwm67uc+HMVkwhEZUk7ljnEeLICS3c bMta2W4onT6TXa+2i/KCYf0Ha/+rmpBZIQD6bSj5aZuZLg4Q8wxougqLHYm1s2BS018C yA9RPfAOmKAsMXANo4hI3MWc7sGJHH/ueUR3ko8PmniU/BAx/+KDIPGOlXYwJM/vipC7 lVPeUVtk8I+mD1l3+wGZqKHcHdhzyfpZWzi7LvOMxmGNyOnRtc4JEaTFPlTSkAk2bO0H gH5UpL1BjudRLTATUcUaVgZ5ysnNo1cwpSwX9/a0peagmssIRLdb3KdEXxBU+yPqKELF mQag== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=qTucIh8q1fOUaY+KKBj6aQtvZjzoQVm4j1aVcrELJdg=; b=sKytYddV4y95dP1gNJZzOGT3O0RKhmBDdGk/SycIJW1wI5x+Y/gHTgjWsImx0RCv11 eL1cnWSReVNRnvxbg7TaXq2HpYpZkM3j6sSgw1rRfeCHt4mtKedgn2RZcaI7YIJYcQKX dySLTgXMvAs3vBHJmiUZLR/9Ix1Jjo+Y7coUX/Ozx5xOhIGwLGQgQPxliqS5IBCU8awR 2tdkdauxUBaFT6GE3YDNh9z/0pabaEFAcrBn5QDKPvafrgO/Kh8K8M4bOvwh9vCWaVhJ SBOA8pKly7WnCDADNE0i7eL40wJy9QuVFv/4tlUaCjEXPK9LlKJel+68xgCMpt6GHRVT 3ogQ== X-Gm-Message-State: APjAAAWKjjZje5JugUyv90ZZfkn2UTRiLlHnZYPjS/20yaoOyaIlBrbz r5IrNeNWpxNxpvQSQw0KCTE= X-Google-Smtp-Source: APXvYqzg5q+zi7l62CSsBi+FVAyvyazN/rsqBHQwchbTMquy6ZBbE0QNAtXa4cgIoVKUr37UmaMV1Q== X-Received: by 2002:a62:834c:: with SMTP id h73mr1420640pfe.183.1568769951670; Tue, 17 Sep 2019 18:25:51 -0700 (PDT) Received: from localhost ([175.223.34.14]) by smtp.gmail.com with ESMTPSA id q2sm5322354pfg.144.2019.09.17.18.25.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 17 Sep 2019 18:25:50 -0700 (PDT) Date: Wed, 18 Sep 2019 10:25:46 +0900 From: Sergey Senozhatsky To: John Ogness Cc: Linus Torvalds , Thomas Gleixner , Steven Rostedt , Peter Zijlstra , Petr Mladek , Andrea Parri , Sergey Senozhatsky , Sergey Senozhatsky , Brendan Higgins , Greg Kroah-Hartman , LKML , Theodore Ts'o , Paul Turner , Daniel Vetter , Prarit Bhargava Subject: Re: printk meeting at LPC Message-ID: <20190918012546.GA12090@jagdpanzerIV> References: <20190807222634.1723-1-john.ogness@linutronix.de> <20190904123531.GA2369@hirez.programming.kicks-ass.net> <20190905130513.4fru6yvjx73pjx7p@pathway.suse.cz> <20190905143118.GP2349@hirez.programming.kicks-ass.net> <20190905121101.60c78422@oasis.local.home> <87k1acz5rx.fsf@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87k1acz5rx.fsf@linutronix.de> User-Agent: Mutt/1.12.1 (2019-06-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On (09/13/19 15:26), John Ogness wrote: > 2. A kernel thread will be created for each registered console, each > responsible for being the sole printers to their respective > consoles. With this, console printing is _fully_ decoupled from printk() > callers. sysrq over serial? What we currently have is hacky, but, as usual, is a "best effort": >> serial driver IRQ serial_handle_irq() [console driver] uart_handle_sysrq_char() handle_sysrq() printk() call_console_drivers() serial_write() [re-enter console driver] offloading this to kthread may be unreliable. -ss