Messages in this thread | | | Date | Tue, 27 Jul 2010 23:38:03 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH 31/31] memblock: Add memblock_find_in_range() |
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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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