Re: [PATCH 31/31] memblock: Add memblock_find_in_range()

[H. Peter Anvin]

On 07/27/2010 11:08 PM, Yinghai Lu wrote:
> 
> for example: 
> high/low allocation, from first kernel to kexec second kernel, always work fine except system with Qlogic card.
> because Qlogic card is using main RAM as EFT etc for card's FW log trace. second kernel have not idea that those RAM
>  is used by first kernel for that purpose. that the CARD still use that between two kernels.
> second kernel could have crash it try to use those ram.
> 

Uhm, no.  That's a bug in the Qlogic driver not shutting the card down
cleanly.  Hacking around that in memory allocation order is braindamaged
in the extreme.  kexec *cannot* be safe in any way if we don't shut down
pending DMA, and what you describe above is DMA.

> low/high allocation seems to be safe,  second kernel can slip to boot fine.

Low to high is just broken.  Low memory is a special, desirable
resource, and we should minimize the use of it.

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.

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