Re: [Tails-dev] Please review feature/hugetlb_mem_wipe

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Author: intrigeri
Date:  
To: The Tails public development discussion list
Subject: Re: [Tails-dev] Please review feature/hugetlb_mem_wipe
Hi,

anonym wrote (09 Oct 2012 14:17:45 GMT) :
> * feature/hugetlb_mem_wipe:


>   - With PAE kernel:
>     * Patterns remaining after wipe: ~39K ≃ 600 KiB of memory
>     * Time required for wipe: 2.5 seconds.


>   - With "normal" non-PAE kernel:
>     * Patterns remaining after wipe: 51K ≃ 800 KiB of memory. Also, in
>       this case hugetlb_mem_wipe exits at 51% progress with the
>       following error:
>       [...]
>     * Time required for wipe: ~1 second.


This looks very promising!

Ague, what are the advantages of this solution, compared to the "fill
a tmpfs" idea you also had?

(The latter would arguably have a simpler implementation, that most of
us could understand and debug, contrary to the fancy hugetlb_mem_wipe
one. Simplicity matters.)

> * devel (many `sdmem` in parallel thanks to 0f1f476d):


>   - With PAE kernel:
>     * Patterns remaining after wipe: 0 (!)
>     * Time required for wipe: 8 seconds.


>   - With "normal" non-PAE kernel:
>     * Patterns remaining after wipe: 900K ≃ 14 MiB of memory
>     * Time required for wipe: 4 seconds.


anonym, how many such tests did you run?
I find it intriguing that the PAE and non-PAE results differ.

> I'd rather wait with merging feature/hugetlb_mem_wipe until after
> Tails 0.14.


Agreed.

Cheers,
--
intrigeri
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