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Date: Tue, 9 Jan 2018 17:47:50 -0500
From: Steven Rostedt <rostedt@goodmis.org>
To: Tejun Heo <tj@kernel.org>
Cc: Petr Mladek <pmladek@suse.com>,
        Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
        Jan Kara <jack@suse.cz>,
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        linux-kernel@vger.kernel.org,
        Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Subject: Re: [RFC][PATCHv6 00/12] printk: introduce printing kernel thread
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On Tue, 9 Jan 2018 14:17:05 -0800
Tejun Heo <tj@kernel.org> wrote:

> Hello, Steven.
> 
> On Tue, Jan 09, 2018 at 05:08:47PM -0500, Steven Rostedt wrote:
> > The scenario you listed would affect multiple CPUs and multiple CPUs
> > would be flooding printk. In that case my patch WILL help. Because the
> > current method, the first CPU to do the printk will get stuck doing the
> > printk for ALL OTHER CPUs. With my patch, the printk load will migrate
> > around and there will not be a single CPU that is stuck.  
> 
> Maybe it can break out eventually but that can take a really long
> time.  It's OOM.  Most of userland is waiting for reclaim.  There
> isn't all that much going on outside that and there can only be one
> CPU which is OOMing.  The kernel isn't gonna be all that chatty.

Are you saying that the OOM is stuck printing over and over on a single
CPU. Perhaps we should fix THAT.

-- Steve