Date: Tue, 16 Jan 2018 13:51:31 +0900
From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Petr Mladek <pmladek@suse.com>,
        Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
        Tejun Heo <tj@kernel.org>,
        Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
        akpm@linux-foundation.org, linux-mm@kvack.org,
        Cong Wang <xiyou.wangcong@gmail.com>,
        Dave Hansen <dave.hansen@intel.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Mel Gorman <mgorman@suse.de>, Michal Hocko <mhocko@kernel.org>,
        Vlastimil Babka <vbabka@suse.cz>,
        Peter Zijlstra <peterz@infradead.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Jan Kara <jack@suse.cz>,
        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
        rostedt@home.goodmis.org, Byungchul Park <byungchul.park@lge.com>,
        Pavel Machek <pavel@ucw.cz>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5 0/2] printk: Console owner and waiter logic cleanup
Message-ID: <20180116045131.GF6607@jagdpanzerIV>
References: <20180111045817.GA494@jagdpanzerIV>
 <20180111093435.GA24497@linux.suse>
 <20180111103845.GB477@jagdpanzerIV>
 <20180111112908.50de440a@vmware.local.home>
 <20180112025612.GB6419@jagdpanzerIV>
 <20180111222140.7fd89d52@gandalf.local.home>
 <20180112100544.GA441@jagdpanzerIV>
 <20180112072123.33bb567d@gandalf.local.home>
 <20180112125536.GC24497@linux.suse>
 <20180115070821.40f044d6@gandalf.local.home>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20180115070821.40f044d6@gandalf.local.home>
User-Agent: Mutt/1.9.2 (2017-12-15)
Sender: linux-kernel-owner@vger.kernel.org

On (01/15/18 07:08), Steven Rostedt wrote:
> On Fri, 12 Jan 2018 13:55:37 +0100
> Petr Mladek <pmladek@suse.com> wrote:
> 
> > > I'm not fixing console_unlock(), I'm fixing printk(). BTW, all my
> > > kernels are CONFIG_PREEMPT (I'm a RT guy), my mind thinks more about
> > > PREEMPT kernels than !PREEMPT ones.  
> > 
> > I would say that the patch improves also console_unlock() but only in
> > non-preemttive context.
> > 
> > By other words, it makes console_unlock() finite in preemptible context
> > (limited by buffer size). It might still be unlimited in
> > non-preemtible context.
> 
> Since I'm worried most about printk(), I would argue to make printk
> console unlock always non-preempt.

+1


// The next stop is "victims of O(logbuf) memorial" station :)

	-ss