Re: Does Linux have plan to support memory hole remapping?

From: Zhao Forrest
Date: Wed Apr 09 2008 - 05:04:46 EST


On 4/9/08, Andi Kleen <andi@xxxxxxxxxxxxxx> wrote:
> "Zhao Forrest" <forrest.zhao@xxxxxxxxx> writes:
> >
> > As we can see from above information that the physical memory in system
> > is 32768MB(32GB). However OS is only using about
> > (32768-512)MB(MemTotal: 33010240 kB). Does this mean that this
> > linux kernel can't use the physical memory remapped
> > from (4G-512M, 4G) to (32G, 32G+512M)?
>
> The linux kernel can only use the memory passed to it by the BIOS.
> Sometimes they need special BIOS setup options to enable remapping. If
> there are no such options and you can't upgrade it you're out of luck

Yes, I have enabled mem hole remapping in BIOS SETUP.
After looking into dmesg, I found that all 32GB physical memory has
been allocated to 8 nodes, but why MemTotal shows a less amount of
memory than 32GB? Interesting......
Does MemTotal means the amount of physical memory allocated to all
nodes? Or it has different meanings?

Thanks,
Forrest
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