linux-kernel - Re: IRQ off latency of printk is very high

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20071025231237.GT19691@waste.org>
Date:	Thu, 25 Oct 2007 18:12:38 -0500
From:	Matt Mackall <mpm@...enic.com>
To:	Tim Bird <tim.bird@...sony.com>
Cc:	Mathieu Desnoyers <mathieu.desnoyers@...ymtl.ca>,
	linux kernel <linux-kernel@...r.kernel.org>,
	Ingo Molnar <mingo@...hat.com>, Jon Smirl <jonsmirl@...oo.com>
Subject: Re: IRQ off latency of printk is very high

On Thu, Oct 25, 2007 at 03:52:28PM -0700, Tim Bird wrote:
> Mathieu Desnoyers wrote:
> > It might help to read this thread I posted on LKML in January 2006
> > explaining the problem, which led to some discussion about the issue.
> > 
> > http://lkml.org/lkml/2006/6/3/48
> 
> This is very helpful.  Jon Smirl's answer seems to give the
> rationale for supporting printk output in interrupt context.
> I'm not sure, however, if extending the interrupt off period
> to cover the console output is required.  It didn't until
> Ingo changed it in 2.6.17.

Hmm, I see this at the beginning of the post-BK era (2.6.12-rc2):

	        spin_lock_irqsave(&logbuf_lock, flags);
		...
		spin_unlock(&logbuf_lock);
		call_console_drivers(_con_start, _log_end);
		local_irq_restore(flags);

-- 
Mathematics is the supreme nostalgia of our time.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/