From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S966176AbdLSBKF (ORCPT <rfc822;w@1wt.eu>);
        Mon, 18 Dec 2017 20:10:05 -0500
Received: from mail-pf0-f195.google.com ([209.85.192.195]:36861 "EHLO
        mail-pf0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S935898AbdLSBKE (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Mon, 18 Dec 2017 20:10:04 -0500
X-Google-Smtp-Source: ACJfBounllfqS68dIbteAa7rX2PB8Fg34Avp6Gq5qb4WCB8bno3DH063S2Jx6y/3ziVB6RiYGodu6A==
Date: Tue, 19 Dec 2017 10:09:59 +0900
From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
        Steven Rostedt <rostedt@goodmis.org>, Tejun Heo <tj@kernel.org>,
        Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
        Jan Kara <jack@suse.cz>, Andrew Morton <akpm@linux-foundation.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Rafael Wysocki <rjw@rjwysocki.net>, Pavel Machek <pavel@ucw.cz>,
        Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
        linux-kernel@vger.kernel.org
Subject: Re: [RFC][PATCHv6 00/12] printk: introduce printing kernel thread
Message-ID: <20171219010959.GA17164@jagdpanzerIV>
References: <20171214181153.GZ3919388@devbig577.frc2.facebook.com>
 <20171215021024.GA11199@jagdpanzerIV>
 <20171214221831.3ead0298@vmware.local.home>
 <20171215050607.GC11199@jagdpanzerIV>
 <20171215083151.cu3xbdgmxqkszwso@pathway.suse.cz>
 <20171215084236.GE468@jagdpanzerIV>
 <20171215090801.eulx4pg54p667ya5@pathway.suse.cz>
 <20171218093405.GA31274@jagdpanzerIV>
 <20171218133101.ri55uwivhc5xwg5y@pathway.suse.cz>
 <20171218141037.m6o6bicx5xhpjbl6@pathway.suse.cz>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20171218141037.m6o6bicx5xhpjbl6@pathway.suse.cz>
User-Agent: Mutt/1.9.2 (2017-12-15)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On (12/18/17 15:10), Petr Mladek wrote:
[..]
> > All this is in the current upstream code as well. Steven's patch
> > should make it better in compare with the current upstream code.
> > 
> > Sure, the printk offload approach does all these things better.
> > But there is still the fear that the offload is not reliable
> > in all situations. The lazy offload should handle this well from
> > my POV but I am not 100% sure.
> 
> BTW: There is one interesting thing. If we rely on the kthread
> to handle flood of messages. It might be too slow because it
> reschedules. It might cause loosing messages. Note that
> the kthread should have rather normal priority to avoid
> blocking other processes.

... and this is why preemption is disabled in console_unlock()
in the patch set I have posted.

obviously you haven't even looked at the patches. wonderful.

	-ss