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From: Arjan van de Ven <arjan@infradead.org>
To: Bill Irwin <bill.irwin@oracle.com>
Cc: Hugh Dickins <hugh@veritas.com>,
	Chuck Ebbert <cebbert@redhat.com>,
	Andi Kleen <andi@firstfloor.org>,
	linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: Wanted: simple, safe x86 stack overflow detection
Date: Wed, 07 Mar 2007 07:04:23 -0800	[thread overview]
Message-ID: <1173279863.3540.2.camel@laptopd505.fenrus.org> (raw)
In-Reply-To: <20070307144816.GQ18774@holomorphy.com>


> > just removing the if() and the explicit IRQ enabling already makes irqs no longer nest...
> 
> I can see why that would raise eyebrows. I can see getting bashed
> mercilessly with interrupt latency concerns as a result here. Can you
> suggest any defenses?


hardirq handlers are supposed to be fast. If they're slow the code
should (and generally is) using bottom halves/tasklets/softirqs. Combine
this with the fact that each new irq handler will start with a bunch of
cache misses, the latency added isn't generally that significant. In
addition, the cache miss thing makes the nesting suck a lot, it's faster
to batch the irqs in sequence.

-- 
if you want to mail me at work (you don't), use arjan (at) linux.intel.com
Test the interaction between Linux and your BIOS via http://www.linuxfirmwarekit.org


  reply	other threads:[~2007-03-07 15:05 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-02-28 14:27 Chuck Ebbert
2007-02-28 16:31 ` Thiago Galesi
2007-02-28 20:41 ` Andi Kleen
2007-02-28 23:20   ` Bill Irwin
2007-02-28 23:36     ` Jan Engelhardt
2007-02-28 23:45       ` Bill Irwin
2007-03-04  1:50   ` Bill Irwin
2007-03-06 18:59     ` Chuck Ebbert
2007-03-06 19:43       ` Hugh Dickins
2007-03-06 20:34         ` Bill Irwin
2007-03-07  4:28           ` Arjan van de Ven
2007-03-07  6:44             ` Bill Irwin
2007-03-07 12:34               ` Arjan van de Ven
2007-03-07 14:48                 ` Bill Irwin
2007-03-07 15:04                   ` Arjan van de Ven [this message]
2007-03-08  7:43                   ` Avi Kivity
2007-03-19 20:53                     ` Eric W. Biederman
2007-03-06 20:06       ` Bill Irwin
2007-03-05  1:18 ` Arnd Bergmann
2007-03-05 12:39   ` Andi Kleen

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