From: Jamie Lokier <jamie@shareable.org>
To: Anton Blanchard <anton@samba.org>
Cc: Robert_Hentosh@Dell.com, linux-kernel@vger.kernel.org
Subject: Re: spurious 8259A interrupt
Date: Fri, 19 Mar 2004 14:56:55 +0000 [thread overview]
Message-ID: <20040319145655.GE3897@mail.shareable.org> (raw)
In-Reply-To: <20040319140455.GB1153@krispykreme>
Anton Blanchard wrote:
> > Indeed. But why? What's the advantage?
>
> We enable IRQs during IRQ processing on ppc64 for one reason. We set the
> IPI priority higher than normal IRQs so we can service it as soon as
> possible and the calling cpu can move on.
Yes: when there are interrupt priorities, then enabling them at the
CPU and masking them at the controller is required.
Is that the reason for masking 8259 interrupts on x86 Linux?
I.e. are there any special "high priority" interrupts used on x86 Linux?
Otherwise, I don't see why we have the overhead of the extra I/O
operations to mask and unmask them. I'm sure there's a very good
reason: Linus wouldn't have written or accepted that code unless there
was a very good reason. But I would love to know what it is!
-- Jamie
next prev parent reply other threads:[~2004-03-19 14:57 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-03-16 20:32 spurious 8259A interrupt Robert_Hentosh
2004-03-19 13:06 ` Jamie Lokier
2004-03-19 13:16 ` Russell King
2004-03-19 13:39 ` Jamie Lokier
2004-03-19 14:04 ` Anton Blanchard
2004-03-19 14:56 ` Jamie Lokier [this message]
2004-03-19 13:48 ` Richard B. Johnson
2004-03-19 14:39 ` Jamie Lokier
2004-03-21 17:58 ` Hans-Peter Jansen
2004-03-22 9:12 ` Maciej W. Rozycki
2004-03-22 12:29 ` Richard B. Johnson
2004-03-24 15:28 ` Jamie Lokier
2004-03-24 15:50 ` Gabriel Paubert
2004-03-24 15:57 ` Richard B. Johnson
2004-03-19 13:28 ` Maciej W. Rozycki
2004-03-19 22:01 ` Guennadi Liakhovetski
2004-03-22 9:02 ` Maciej W. Rozycki
2004-03-22 21:16 ` Guennadi Liakhovetski
2004-03-22 22:13 ` Richard B. Johnson
2004-03-22 23:09 ` Guennadi Liakhovetski
2004-03-22 23:38 ` Richard B. Johnson
2004-03-23 10:32 ` Maciej W. Rozycki
2004-03-23 10:42 ` Maciej W. Rozycki
2004-03-23 21:10 ` Guennadi Liakhovetski
2004-03-23 10:29 ` Maciej W. Rozycki
2004-03-23 10:26 ` Maciej W. Rozycki
-- strict thread matches above, loose matches on Subject: below --
2004-03-16 18:35 Emmanuel Fleury
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