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From: "H. Peter Anvin" <hpa@zytor.com>
To: Rob Landley <rob@landley.net>
Cc: Ingo Molnar <mingo@elte.hu>, linux-kernel@vger.kernel.org
Subject: Re: 2.6.24 says "serial8250: too much work for irq4" a lot.
Date: Thu, 07 Feb 2008 12:53:43 -0800	[thread overview]
Message-ID: <47AB6FD7.1030502@zytor.com> (raw)
In-Reply-To: <200802071413.45085.rob@landley.net>

Rob Landley wrote:
> 
> Specifically, qemu isn't paravirtualized, it's fully virtualized.  The same 
> kernel can run on real hardware just fine.  (Sort of the point of the 
> project...)
> 
> I can yank the warning for the kernels I build (or set PASS_LIMIT to 9999999), 
> but I'd rather not carry any more patches than I can avoid...
> 

The right thing to do is to add virtual FIFO exhaustion into the Qemu 
device model.  It really isn't a valid emulation of a UART that it has 
an infinite FIFO behind it that can flood the interrupt handler for an 
arbitrary number of fetches.

I was going to give a technical description of how to do it here, but 
then I realized I might as well just write it up as a patch.  Stay tuned.

	-hpa


  reply	other threads:[~2008-02-07 21:12 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-05 20:55 2.6.24 says "serial8250: too much work for irq4" a lot Rob Landley
2008-02-05 21:07 ` H. Peter Anvin
2008-02-06  0:43   ` [Qemu-devel] " Rob Landley
2008-02-07 12:39   ` Ingo Molnar
2008-02-07 17:37     ` H. Peter Anvin
2008-02-07 20:13       ` Rob Landley
2008-02-07 20:53         ` H. Peter Anvin [this message]
2008-02-07 21:19         ` H. Peter Anvin
2008-02-08  7:04           ` Rob Landley
2008-02-09  5:49           ` [Qemu-devel] " Rob Landley
2008-02-09  7:04             ` Blue Swirl
2008-02-09  7:12               ` H. Peter Anvin
2008-02-09 11:15                 ` Blue Swirl
2008-02-09 21:36                   ` H. Peter Anvin
2008-02-10  8:01                     ` Blue Swirl
2008-02-10 11:26                       ` Paul Brook
2008-03-11 23:51                         ` Aurelien Jarno

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