From: Ingo Molnar <mingo@elte.hu>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Greg KH <greg@kroah.com>, "Theodore Ts'o" <tytso@mit.edu>,
Linus Torvalds <torvalds@linux-foundation.org>,
Alan Cox <alan@lxorguk.ukuu.org.uk>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: printk() vs tty_io
Date: Wed, 14 Dec 2011 10:46:43 +0100 [thread overview]
Message-ID: <20111214094643.GA8115@elte.hu> (raw)
In-Reply-To: <1323855797.28489.22.camel@twins>
* Peter Zijlstra <peterz@infradead.org> wrote:
> On Wed, 2011-12-14 at 07:59 +0100, Ingo Molnar wrote:
>
> > btw., would be nice to also somehow realeasify those debug
> > hacks to preserve them for eternity - doing all lockdep
> > output as earlyprintk while keeping printks working is a
> > great way to debug printk() itself.
> >
> > Those printk lockups also took a *lot* of time for me to
> > bisect.
>
> Yeah, they're horrible.. took me long enough to reproduce, and
> even now I know how its not easy.
>
> Anyway, I just posted the two patches that make lockdep do
> early_printk(), they're not too horrid. [...]
Given how crutial lockdep is to analyzing lockups, i think this
decoupling from printk() innards is a good idea in general.
[ It also rhymes well with the general principles of lockdep, to
create all of its infrastructure from scratch, to be able to
use it everywhere. ]
The small lprintk() ugliness we can live with i think.
Thanks,
Ingo
next prev parent reply other threads:[~2011-12-14 9:48 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-13 19:33 printk() vs tty_io Peter Zijlstra
2011-12-13 23:52 ` Linus Torvalds
2011-12-14 9:38 ` Peter Zijlstra
2011-12-14 10:43 ` Alan Cox
2011-12-14 10:56 ` Peter Zijlstra
2011-12-14 14:05 ` Ted Ts'o
2011-12-14 14:23 ` Peter Zijlstra
2011-12-14 15:54 ` Linus Torvalds
2011-12-15 9:56 ` Peter Zijlstra
2011-12-15 10:32 ` Alan Cox
2011-12-15 10:55 ` Peter Zijlstra
2011-12-15 17:08 ` Linus Torvalds
2011-12-15 18:07 ` Ingo Molnar
2011-12-15 21:22 ` Alan Cox
2011-12-16 13:25 ` Peter Zijlstra
2011-12-15 19:02 ` Greg KH
2011-12-14 6:59 ` Ingo Molnar
2011-12-14 9:40 ` [PATCH] arch, early_printk: Consolidate early_printk() implementations Peter Zijlstra
2011-12-14 9:41 ` [PATCH] lockdep: Enable earlyprintk output Peter Zijlstra
2011-12-14 9:43 ` printk() vs tty_io Peter Zijlstra
2011-12-14 9:46 ` Ingo Molnar [this message]
2011-12-21 12:03 ` Stijn Devriendt
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