linux-kernel - Re: [PATCH 09/10] MCE: run through processors with more severe problems first

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Date:	Fri, 10 Jun 2011 17:09:26 +0900
From:	Hidetoshi Seto <seto.hidetoshi@...fujitsu.com>
To:	"Luck, Tony" <tony.luck@...el.com>
CC:	Ingo Molnar <mingo@...e.hu>, Borislav Petkov <bp@...64.org>,
	linux-kernel@...r.kernel.org, "Huang, Ying" <ying.huang@...el.com>,
	Avi Kivity <avi@...hat.com>
Subject: Re: [PATCH 09/10] MCE: run through processors with more severe problems
 first

(2011/06/10 6:37), Luck, Tony wrote:
> From: Tony Luck <tony.luck@...el.com>
> 
> Instead of letting cpus run through the MC bank scanning code
> in the order that they turned up in the handler, we arrange to
> deal with those that have more severe problems (mcgstatus.ripv=0)
> first. This will make life simpler in the case that banks are
> shared between processors, since the cpu with the problem will
> see it and clear it, leaving the other cpu(s) that share the
> bank with nothing to do.

Well, I agree about the point that reordering is required to handle
shared banks. 

I think it is better to put this change in early of the series. 

> 
> Signed-off-by: Tony Luck <tony.luck@...el.com>
> ---
(snip)
> +/*
> + * next cpu choosing first from cant_return, and then from can_return
> + */
> +int mce_nextcpu(int this)
> +{
> +	int next;
> +
> +	if (this == -1 || cpumask_test_cpu(this, &cant_return)) {
> +		next = cpumask_next(this, &cant_return);
> +		if (next >= nr_cpu_ids)
> +			next = cpumask_next(-1, &can_return);
> +		return next;
> +	}
> +
> +	return cpumask_next(this, &can_return);
> +}

I don't like to have multiple cpumasks here, notably one is just an
inversion of another... 

How about using severity-leveling?
Pick cpus with PANIC level first, then AR, AO ...

Or how about checking rip in each mces_seen?


Thanks,
H.Seto

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