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=-2.2 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 21F30C4CEC9 for ; Wed, 18 Sep 2019 09:11:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E8270206C2 for ; Wed, 18 Sep 2019 09:11:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Rq/d9Do/" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728873AbfIRJLG (ORCPT ); Wed, 18 Sep 2019 05:11:06 -0400 Received: from mail-pg1-f195.google.com ([209.85.215.195]:34189 "EHLO mail-pg1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726077AbfIRJLF (ORCPT ); Wed, 18 Sep 2019 05:11:05 -0400 Received: by mail-pg1-f195.google.com with SMTP id n9so3675170pgc.1 for ; Wed, 18 Sep 2019 02:11:05 -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=6uvS0UZ6H/zDo06Y5m/KUvTD9XX9l52PqJXfvtuw9xA=; b=Rq/d9Do/vXMKTUN8PzO+7daKezpcMdb+iT3YDE/xO0xQi6g4o+VugW6g+fV1Kq2X0B ZgddWfj4B1snpD3KlnFQtSqrRkZG4QdlWt5W24clVUTPk+2Ot49LLGEeyMk7XSq4756Z /5/6AN8l5Vuu+ENLg1Mal2K+3mVSXsrn7DAmy3jeVx0R0Tx/pt9stNqzop2gOFbEteiu 2elnrgs1vdKGhLfks+f2UOgLUvMWKSSOTMTbYbVi9Cb4RL5w7R2xZUvXeWxjkNlA/FSu LbLNKGts7oZkyzYaT20zHc5XLqviPDSCpIVUrDXLGZsgvg2F5e0ikjvTwkbycidm7YmE AuEA== 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=6uvS0UZ6H/zDo06Y5m/KUvTD9XX9l52PqJXfvtuw9xA=; b=sK4VZ5gNlhZNHLzT9KvxbwwFN3SjwxGIpGUzfDYMrNyL3QPMrVHAk6FiW5pMbomcFv eQuGDgRffvLoiMs3NjZT2mIq2xcej41bcgoxKvocwN9TjhTWxxo01DZklj5S2MHCOdWG 772p0rxxw7qGLUB9OwWM+qJeGYeyIWMOnM4oZ1cdZmq1b0yGze0GdfVTlmDsxoB2+6hc xjL7uwfnYc8T01wpgk5gkPvvGL0o9GJ5oGrZQRhH+UyT1qn0wP/pSl6Qhm5RhQGHQ4rv TpQCPFNtYkzL6ieWm+5+Vq88PMxecsIySDMrdEavdEvMfgxfYuwuIjQ2/f+WRkeTC24g lKlA== X-Gm-Message-State: APjAAAUrdpIxCgDcvvfnu9JF+Eun3zN7PYj75sLL8uWjM77Iw0VieyJg S0pTgSidMdD8H+4ZqYliIso= X-Google-Smtp-Source: APXvYqwAOJDM8xwsbkbeHIRmCEaj63zG1exnj6TSDu7k/r8474gxLnDnS3r/INCJ43qGMUY1DIRNMg== X-Received: by 2002:a63:5222:: with SMTP id g34mr2777904pgb.405.1568797864898; Wed, 18 Sep 2019 02:11:04 -0700 (PDT) Received: from localhost ([175.223.34.14]) by smtp.gmail.com with ESMTPSA id 62sm5946596pfg.164.2019.09.18.02.11.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 18 Sep 2019 02:11:04 -0700 (PDT) Date: Wed, 18 Sep 2019 18:11:00 +0900 From: Sergey Senozhatsky To: John Ogness Cc: Sergey Senozhatsky , Steven Rostedt , Linus Torvalds , Thomas Gleixner , Peter Zijlstra , Petr Mladek , Andrea Parri , 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: <20190918091100.GA55364@jagdpanzerIV> References: <20190905121101.60c78422@oasis.local.home> <87k1acz5rx.fsf@linutronix.de> <20190918012546.GA12090@jagdpanzerIV> <20190917220849.17a1226a@oasis.local.home> <20190918023654.GB15380@jagdpanzerIV> <20190918051933.GA220683@jagdpanzerIV> <87h85anj85.fsf@linutronix.de> <20190918081012.GB37041@jagdpanzerIV> <877e66nfdz.fsf@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <877e66nfdz.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 (09/18/19 11:05), John Ogness wrote: > On 2019-09-18, Sergey Senozhatsky wrote: > >> Each console has its own iterator. This iterators will need to > >> advance, regardless if the message was printed via write() or > >> write_atomic(). > > > > Great. > > > > ->atomic_write() path will make sure that kthread is parked or will > > those compete for uart port? > > A cpu-lock (probably per-console) will be used to synchronize the > two. Unlike my RFCv1, we want to keep the cpu-lock out of the console > drivers and we want it to be less aggressive (using trylock's instead of > spinning). That's my expectation as well. cpu-lock and per-console kthread can live just fine in printk.c file. -ss