Re: get_user_pages and pinning

[Cengiz Can]

Hello Sadanand

On January 2, 2021 3:39:08 PM GMT+03:00, Sadanand Warrier 
 wrote:
>Folks
>   Since Linux uses lazy evaluation with respect to allocating memory
>what happens if a user process allocates memory using malloc in excess
>of say 8 or nine pages and calls a device ioctl and passes the user
>space pointer to it to be used to pin pages using get_user_pages().

I don't have an answer to your question because your sentences are too long and 
I couldn't understand the thing you are asking. 

>This buffer is to be used for a dma read from a device.
>What happens if the memory isn't actually allocated (no initialization
>with memset or calloc etc. and all PTEs are pointing to some zero
>filled page) and there is no IOMMU?
>Thanks
>
>S

 Please use punctuation marks as termination points and keep your sentences 
shorter for better responses from any community. 

Thank you 

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Re: BUG: Bad page state in process swapper on new imx8qm board

[Cengiz Can]

Hello Oliver,

> So after some more digging I assume that this error is related to a
> missing "reserved-memory" node in my devicetree. Now I need to find
> out how to split up my memory the right way for this imx8qm congatec
> board.

I think asking in #linux-imx (freenode) would be a much better idea.

You can use https://webchat.freenode.net/ if you don't have an IRC
client handy.

Good luck!

-- 
Cengiz Can


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