Messages in this thread | | | Date | Fri, 6 Apr 2012 14:21:38 +0800 | Subject | Re: Some questions about high memory | From | loody <> |
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hi mulyadi
2012/4/6 Mulyadi Santosa <mulyadi.santosa@gmail.com>: > Hi... > > On Fri, Apr 6, 2012 at 09:19, loody <miloody@gmail.com> wrote: >> hi all: >> I am trying to write a driver for my block device which dma support >> high memory copying. >> I have register my device as "blk_bounce_any". >> But my driver cannot see block layer pass high memory to me so far. > > perhaps because you need to kmap them first? If I remember correctly, Kmap is used for mapping high memory into kernel virtual memory. Isn't that the job for block layer?
I thought once I declare my block device as "blk_bounce_any", the block layer will pass the physical address of high memory to device.
> > BTW, is it 32 bit or 64 bit Linux kernel? 32-bits linux kernel.
> >> Is there any user/kernel test program which will purposely send high >> memory for driver to use? >> or is there any flag when opening a file in user mode that will use high memory? > > I recheck mmap and mmap manual page and I found none of such flag
does that mean mmap can specify which memory to map? if that is true, which range I should use?
> > -- > regards, > > Mulyadi Santosa > Freelance Linux trainer and consultant > > blog: the-hydra.blogspot.com > training: mulyaditraining.blogspot.com
Appreciate your help
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