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Date: Thu, 25 Mar 2010 19:44:37 +0100
From: Andi Kleen <andi@firstfloor.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
       Thomas Gleixner <tglx@linutronix.de>, Andi Kleen <andi@firstfloor.org>,
       x86@kernel.org, LKML <linux-kernel@vger.kernel.org>,
       jesse.brandeburg@intel.com, Arjan Van De Ven <arjan@infradead.org>
Subject: Re: [PATCH] Prevent nested interrupts when the IRQ stack is near overflowing v2
Message-ID: <20100325184437.GS20695@one.firstfloor.org>
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On Thu, Mar 25, 2010 at 07:23:58PM +0100, Peter Zijlstra wrote:
> On Thu, 2010-03-25 at 19:21 +0100, Peter Zijlstra wrote:
> > On Thu, 2010-03-25 at 11:01 -0700, Linus Torvalds wrote:
> > > Are there any cases around 
> > > that still have busy-loop delays based on real-time in their irq handlers? 
> > > I simply don't know. 
> > 
> > I recently found a few in drivers/net/ there's all kinds of funny stuff
> > in there.. not sure how common the matching hardware is though.
> > 
> > One thing we could do is instrument jiffies to yell when its used from
> > hardirq context and fix up these things.
> 
> Also, Arjan mentioned he wanted to sweep the kernel for jiffies users
> and convert them to timer interfaces..

% linux-2.6> gid jiffies | wc -l
7569

Good luck.

-Andi

-- 
ak@linux.intel.com -- Speaking for myself only.