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From: Linus Torvalds <torvalds@linux-foundation.org>
To: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Andi Kleen <andi@firstfloor.org>,
	x86@kernel.org, LKML <linux-kernel@vger.kernel.org>,
	jesse.brandeburg@intel.com
Subject: Re: [PATCH] Prevent nested interrupts when the IRQ stack is near overflowing v2
Date: Thu, 25 Mar 2010 13:53:25 -0700 (PDT)	[thread overview]
Message-ID: <alpine.LFD.2.00.1003251349500.3721@i5.linux-foundation.org> (raw)
In-Reply-To: <alpine.LFD.2.00.1003251206550.3721@i5.linux-foundation.org>



On Thu, 25 Mar 2010, Linus Torvalds wrote:
> 
> And I just checked: even the 8250 serial driver doesn't use IRQF_DISABLED 
> any more, so doing that shouldn't cause any latency issues (sure, the 
> serial driver may interrupt another irq, but another irq can also 
> interrupt the serial driver as things stand now, so the original latency 
> issue with fast irq handlers doesn't actually work these days _anyway_).

Btw, if we really do decide that everybody is IRQF_DISABLED, that really 
should make the whole mask-and-ack issue for the irq controllers go away.

We'd still need it, but only for the very special IDE controller case and 
others who _explicitly_ re-enable interrupts. Those would really have to 
cause the irq to be masked so that we don't get issues with recursive irqs 
of the same kind.

		Linus

  parent reply	other threads:[~2010-03-25 20:58 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-03-24 19:02 Andi Kleen
2010-03-24 20:42 ` Thomas Gleixner
2010-03-24 23:08   ` Thomas Gleixner
2010-03-25  0:36     ` Andi Kleen
2010-03-25  1:46       ` Thomas Gleixner
2010-03-25  9:37         ` Andi Kleen
2010-03-25 11:09           ` Thomas Gleixner
2010-03-25 12:11             ` Andi Kleen
2010-03-25 13:17               ` Thomas Gleixner
2010-03-25 13:32                 ` Andi Kleen
2010-03-25 14:16                   ` Thomas Gleixner
2010-03-25 15:38                     ` Andi Kleen
2010-03-25 16:06                     ` Alan Cox
2010-03-25 16:13             ` Linus Torvalds
2010-03-25 16:17               ` Linus Torvalds
2010-03-25 16:27               ` Ingo Molnar
2010-03-25 16:33                 ` Ingo Molnar
2010-03-25 18:27                 ` Andi Kleen
2010-03-26  4:55                   ` Eric W. Biederman
2010-03-25 16:52               ` Thomas Gleixner
2010-03-25 17:47               ` Peter Zijlstra
2010-03-25 18:01                 ` Linus Torvalds
2010-03-25 18:21                   ` Peter Zijlstra
2010-03-25 18:23                     ` Peter Zijlstra
2010-03-25 18:44                       ` Andi Kleen
2010-03-25 19:01                       ` Ingo Molnar
2010-03-25 18:29                   ` Ingo Molnar
2010-03-25 19:10                     ` Linus Torvalds
2010-03-25 19:42                       ` David Miller
2010-03-25 20:40                         ` Linus Torvalds
2010-03-26  3:33                           ` David Miller
2010-03-25 20:51                         ` Ingo Molnar
2010-03-25 20:53                       ` Linus Torvalds [this message]
2010-03-26  6:10                   ` Andi Kleen
2010-03-25 10:50         ` Alan Cox
2010-03-25 11:16           ` Thomas Gleixner
2010-03-25 11:59             ` Alan Cox
2010-03-25 12:00             ` Andi Kleen
2010-03-25 11:57           ` Andi Kleen

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