From: Peter Zijlstra <peterz@infradead.org>
To: Jan Kara <jack@suse.cz>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Petr Mladek <pmladek@suse.com>,
Andrew Morton <akpm@linux-foundation.org>,
Tejun Heo <tj@kernel.org>, Calvin Owens <calvinowens@fb.com>,
Thomas Gleixner <tglx@linutronix.de>,
Mel Gorman <mgorman@techsingularity.net>,
Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@redhat.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/3] make printk work again
Date: Wed, 19 Oct 2016 11:24:03 +0200 [thread overview]
Message-ID: <20161019092403.GF3102@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20161019070416.GF29967@quack2.suse.cz>
On Wed, Oct 19, 2016 at 09:04:16AM +0200, Jan Kara wrote:
> On Tue 18-10-16 19:08:30, Peter Zijlstra wrote:
> > This basically fixes printk by evading everything it does.
> >
> > There's too many problems with printk, from sleeping locks to broken console
> > drivers. Stop using it.
>
> I agree that printk is fragile and your patches are likely fine for machine
> where you do kernel development. However for production servers with
> hundreds of SCSI LUNs assigned I don't think it is a viable solution - I'm
> pretty sure those machines would take ages to boot (if they ever boot) with
> early_printk implementation. So do you intend this as "the ultimate printk
> solution" or just a "kernel developers debugging aid"? :)
Mostly just to scratch my itch. It also completely kills dmesg, which I
can't see being popular :-) On the plus side, these 3 little patches
seems like something mergable (as opposed to my previous approach which
basically just deleted everything printk). The first also fixes a real,
and long standing, issue with kdb_printk.
But I really do not see how printk and the console drivers as exist
today can ever yield something reliable. We've been stacking band-aids
on it for a while now, and I think we're at the point where we should
say stop this madness.
Either do a complete overhaul and redesign of the entire stack, or just
give up and admit its broken crap and leave it rot.
next prev parent reply other threads:[~2016-10-19 16:16 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-18 17:08 [PATCH 0/3] make printk work again Peter Zijlstra
2016-10-18 17:08 ` [PATCH 1/3] printk: Fix kdb_trap_printk placement Peter Zijlstra
2016-10-19 14:41 ` Petr Mladek
2016-10-19 15:18 ` Peter Zijlstra
2016-10-20 13:02 ` Sergey Senozhatsky
2016-11-29 13:54 ` Petr Mladek
2016-10-18 17:08 ` [PATCH 2/3] early_printk: Add force_early_printk kernel parameter Peter Zijlstra
2016-11-29 14:02 ` Petr Mladek
2016-10-18 17:08 ` [PATCH 3/3] early_printk: Add simple serialization to early_vprintk() Peter Zijlstra
2016-10-18 17:19 ` Steven Rostedt
2016-10-18 17:30 ` Peter Zijlstra
2016-10-18 17:53 ` Steven Rostedt
2016-11-29 14:10 ` Petr Mladek
2016-10-19 7:04 ` [PATCH 0/3] make printk work again Jan Kara
2016-10-19 9:24 ` Peter Zijlstra [this message]
2016-10-19 11:48 ` Sergey Senozhatsky
2016-10-19 12:21 ` Peter Zijlstra
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