From mboxrd@z Thu Jan  1 00:00:00 1970
From: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Date: Fri, 15 Nov 2019 12:36:57 +0900
Subject: [OpenRISC] [PATCH 00/50] Add log level to show_stack()
In-Reply-To: <20191113103922.3dc3e8e9@gandalf.local.home>
References: <20191106030542.868541-1-dima@arista.com>
 <20191106083538.z5nlpuf64cigxigh@pathway.suse.cz>
 <20191108103719.GB175344@google.com>
 <20191108130447.h3wfgo4efjkto56f@pathway.suse.cz>
 <20191111012336.GA85185@google.com>
 <13e72b62-c842-8ed5-5b41-bc1692b28f53@arista.com>
 <20191112021747.GA68506@google.com>
 <20191113103922.3dc3e8e9@gandalf.local.home>
Message-ID: <20191115033657.GA407@tigerII.localdomain>
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To: openrisc@lists.librecores.org

On (19/11/13 10:39), Steven Rostedt wrote:
[..]
> > void show_stack(struct task_struct *task, unsigned long *sp, int log_level)
> > {
> > 	printk_emergency_enter(log_level);
> > 	__show_stack(task, sp);
> > 	printk_emergency_exit();
> > }
> > // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - //
> >
> > show_stack() never schedules, disabling preemption around it should
> > not change anything. Should it be interrupted, we will handle it via
> > preempt count.
>
> Please no! The whole point of the printk rewrite was to allow for
> printk to be preemptible and used in more contexts. The show_stack() can
> be all over the place and is not a fast function. Let's not disable
> preemption for it.

I never said that this code should be used all over the place. What
I did say several times was that this code is for quick debugging,
when one sits behind a slow serial console and wants to tweak loglevel
of all printk-s of a particular context/function only.

	-ss