Re: [PATCH v2 2/3] Generic handling of multi-page exclusions

[HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>]

From: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
Subject: RE: [PATCH v2 2/3] Generic handling of multi-page exclusions
Date: Tue, 15 Apr 2014 04:18:31 +0000

>>> At that time, I chose the current code since it was simpler and safer.
>>> http://www.mail-archive.com/kexec%40lists.infradead.org/msg10207.html
>>>
>>> Don't you like this ?
>>>
>>
>>Sorry. I had forgotten this. We should keep the sanity check
>>there. But in our policy, we should not pass to set_bitmap_cyclic(),
>>pfn and cycle where pfn is not in the cycle. We should chceck that in
>>the caller side and pass pfn in the cycle only.
>>
>>Also, on the current implementation, even if pfn outside a current
>>cycle is passed to set_bitmap_cyclic(), we don't have any means to
>>know that.
>>
>>So, how about warning that only once at runtime?
> 
> Sounds good, it will be helpful to detect bugs in caller side.
> Like this?
> 
> diff --git a/makedumpfile.c b/makedumpfile.c
> index 75092a8..da960ad 100644
> --- a/makedumpfile.c
> +++ b/makedumpfile.c
> @@ -3361,9 +3361,16 @@ int
>  set_bitmap_cyclic(char *bitmap, unsigned long long pfn, int val, struct cycle *cycle)
>  {
>  	int byte, bit;
> +	static int warning = 0;
>  
> -        if (pfn < cycle->start_pfn || cycle->end_pfn <= pfn)
> +        if (pfn < cycle->start_pfn || cycle->end_pfn <= pfn) {
> +		if (!warning) {
> +			MSG("WARNING: PFN out of cycle range. (pfn:%llx, ", pfn);
> +			MSG("cycle:[%llx-%llx])\n", cycle->start_pfn, cycle->end_pfn);
> +			warning = 1;
> +		}
>                  return FALSE;
> +	}
>  
>  	/*
>  	 * If val is 0, clear bit on the bitmap.
> 

Yes, I thought this logic.

--
Thanks.
HATAYAMA, Daisuke


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