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From: Ingo Molnar <mingo@kernel.org>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Andrew Morton <akpm@linux-foundation.org>,
	Paul Gortmaker <paul.gortmaker@windriver.com>,
	Anish Kumar <anish198519851985@gmail.com>,
	Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [GIT PULL v2] printk: Make it usable on nohz cpus
Date: Sat, 8 Dec 2012 16:02:52 +0100	[thread overview]
Message-ID: <20121208150252.GI12011@gmail.com> (raw)
In-Reply-To: <1353200692-6039-1-git-send-email-fweisbec@gmail.com>


* Frederic Weisbecker <fweisbec@gmail.com> wrote:

> Ingo,
> 
> Please pull the printk support in dynticks mode patches that can
> be found at:
> 
>   git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git tags/printk-dynticks-for-mingo-v2
> 
> for you to fetch changes up to 74876a98a87a115254b3a66a14b27320b7f0acaa:
> 
>   printk: Wake up klogd using irq_work (2012-11-18 01:01:49 +0100)
> 
> It is based on v3.7-rc4.
> 
> Changes since previous pull request include support for irq 
> work flush on CPU offlining and acks from Steve. The rest 
> hasn't changed except some comment fix.

Since this changes kernel/printk.c it needs Linus's ack.

I looked through the older submissions but found no good summary 
of these changes: it would be nice if you could write up a good 
high level description of these changes - why has printk based 
kernel message logging become problematic on nohz, what are the 
symptoms to users, and what are the solution alternatives you 
found and please justify the irq_work extension variant you 
picked.

I more or less accept the fact that fixes are needed here, but 
the linecount appears a bit high. It's possibly unavoidable, but 
would be nice to have a discussion of it, as printk is something 
we really, really want to keep as simple as possible.

Thanks,

	Ingo

  parent reply	other threads:[~2012-12-08 15:02 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-11-18  1:04 [GIT PULL v2] printk: Make it usable on nohz cpus Frederic Weisbecker
2012-11-18  1:04 ` [PATCH 1/9] irq_work: Fix racy IRQ_WORK_BUSY flag setting Frederic Weisbecker
2012-11-18  1:04 ` [PATCH 2/9] irq_work: Fix racy check on work pending flag Frederic Weisbecker
2012-11-18  1:04 ` [PATCH 3/9] irq_work: Remove CONFIG_HAVE_IRQ_WORK Frederic Weisbecker
2012-11-18  1:04 ` [PATCH 4/9] nohz: Add API to check tick state Frederic Weisbecker
2012-11-18  1:04 ` [PATCH 5/9] irq_work: Don't stop the tick with pending works Frederic Weisbecker
2012-11-18  1:04 ` [PATCH 6/9] irq_work: Flush work on CPU_DYING Frederic Weisbecker
2012-11-18  1:04 ` [PATCH 7/9] irq_work: Warn if there's still work on cpu_down Frederic Weisbecker
2012-11-18  1:04 ` [PATCH 8/9] irq_work: Make self-IPIs optable Frederic Weisbecker
2012-11-18  1:04 ` [PATCH 9/9] printk: Wake up klogd using irq_work Frederic Weisbecker
2012-12-08 15:02 ` Ingo Molnar [this message]
2012-12-08 22:50   ` [GIT PULL v2] printk: Make it usable on nohz cpus Frederic Weisbecker

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