linux-kernel - Re: [PATCH] x86 apic: Ack all pending irqs when crashed/on kexec

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Date:	Wed, 17 Feb 2010 17:05:20 +0100
From:	Jiri Bohac <jbohac@...e.cz>
To:	linux-kernel@...r.kernel.org
Cc:	mingo@...e.hu, Yinghai Lu <yinghai@...nel.org>,
	akpm@...ux-foundation.org, jbohac@...e.cz
Subject: Re: [PATCH] x86 apic: Ack all pending irqs when crashed/on kexec

On Tue, Feb 16, 2010 at 11:03:10PM +0100, Thomas Renninger wrote:
> with MAX_LOOPS something like 1E9 this would leave plenty of time for the
> pending IRQs to be cleared and would and still cause at most a second of delay
> if the loop were to lock-up for whatever reason.
...
> +	int i, j, acked = 0, max_loops = 0x1E9;

I meant 1E9 == 1000000, not 0x1E9, just to give the kernel a
chance to boot (with a delay) if something is completely wrong.
0x1E9 might be too small.

I also think a warning should be printed in case max_loops decreases to
zero:

> +	    max_loops--;
> +        } while (queued && max_loops > 0);

+	WARN_ON(!max_loops)

Thanks,

-- 
Jiri Bohac <jbohac@...e.cz>
SUSE Labs, SUSE CZ

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