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From: Pavel Machek <pavel-+ZI9xUNit7I@public.gmane.org>
To: Alan Cox <alan-qBU/x9rampVanCEyBjwyrvXRex20P6io@public.gmane.org>
Cc: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org,
	Greg KH <greg-U8xfFu+wG4EAvxtiuMwx3w@public.gmane.org>,
	Avi Kivity <avik-atKUWr5tajBWk0Htik3J/w@public.gmane.org>,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [RFC] Deferred interrupt handling.
Date: Wed, 25 Jul 2007 14:18:14 +0000	[thread overview]
Message-ID: <20070725141813.GE9256@ucw.cz> (raw)
In-Reply-To: <20070718224649.3e49a978-v58gJUvfdfWUJIigds3554dd74u8MsAO@public.gmane.org>

Hi!

I guess this will also allow UIO to work without _any_ kernel parts,
with only slight performance penalty in 'almost-never-happens'
deadlock case?

(Greg, details are below, and better description is in the lkml
thread).
							Pavel

> > - Our dummy handler will always return IRQ_HANDLED in case any other
> > previous
> >   irqaction did not return such. It will also issue the timer and mask
> > the irq in this case.
> 
> Ok
> 
> >   btw, if I'm not mistaken only after bad 99900/100000 the irq is
> > disabled.
> 
> (and with GIT providing that they occurred in a short time period)
> 
> > - If the timer pops before the guest acks the irq, the timer handler
> > will
> >   ack the irq and unmask it. The timer's job is only to prevent
> > deadlocks.
> 
> Ok I see what you are doing. It's either inspired or insane and I am not
> quite sure which of the two. I agree it should work although may cause
> performance crunches now and then and will also need care getting the
> locking right.

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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  parent reply	other threads:[~2007-07-25 14:18 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-07-18  9:53 [RFC] Deferred interrupt handling Or Sagi
2007-07-18 11:30 ` Alan Cox
     [not found]   ` <20070718123040.615795b7-v58gJUvfdfWUJIigds3554dd74u8MsAO@public.gmane.org>
2007-07-18 16:36     ` Dor Laor
     [not found]       ` <64F9B87B6B770947A9F8391472E032160CC16C92-yEcIvxbTEBqsx+V+t5oei8rau4O3wl8o3fe8/T/H7NteoWH0uzbU5w@public.gmane.org>
2007-07-18 16:47         ` Alan Cox
     [not found]           ` <20070718174736.0baf6d0e-v58gJUvfdfWUJIigds3554dd74u8MsAO@public.gmane.org>
2007-07-18 16:46             ` Avi Kivity
     [not found]               ` <469E43D5.70802-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
2007-07-18 16:57                 ` Alan Cox
     [not found]                   ` <20070718175708.6968923e-v58gJUvfdfWUJIigds3554dd74u8MsAO@public.gmane.org>
2007-07-18 16:57                     ` Avi Kivity
     [not found]                       ` <469E4679.205-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
2007-07-18 17:14                         ` Alan Cox
2007-07-18 17:09                 ` Dor Laor
     [not found]                   ` <64F9B87B6B770947A9F8391472E032160CC16D06-yEcIvxbTEBqsx+V+t5oei8rau4O3wl8o3fe8/T/H7NteoWH0uzbU5w@public.gmane.org>
2007-07-18 17:33                     ` Alan Cox
     [not found]                       ` <20070718183358.0a0886aa-v58gJUvfdfWUJIigds3554dd74u8MsAO@public.gmane.org>
2007-07-18 21:29                         ` Dor Laor
     [not found]                           ` <64F9B87B6B770947A9F8391472E032160CC16F3C-yEcIvxbTEBqsx+V+t5oei8rau4O3wl8o3fe8/T/H7NteoWH0uzbU5w@public.gmane.org>
2007-07-18 21:46                             ` Alan Cox
     [not found]                               ` <20070718224649.3e49a978-v58gJUvfdfWUJIigds3554dd74u8MsAO@public.gmane.org>
2007-07-25 14:18                                 ` Pavel Machek [this message]
2007-07-18 22:23                             ` Or Sagi
2007-07-18 19:14                 ` Lennart Sorensen
     [not found]                   ` <20070718191433.GB24545-1wCw9BSqJbv44Nm34jS7GywD8/FfD2ys@public.gmane.org>
2007-07-19  9:23                     ` Avi Kivity
     [not found]                       ` <469F2D8C.7020805-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
2007-07-19 13:17                         ` Lennart Sorensen
     [not found]                           ` <20070719131718.GC5623-1wCw9BSqJbv44Nm34jS7GywD8/FfD2ys@public.gmane.org>
2007-07-19 13:38                             ` Avi Kivity
     [not found]                               ` <469F6941.9010901-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
2007-07-19 16:23                                 ` Lennart Sorensen
2007-07-18 15:57 ` Lennart Sorensen

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