Re: [elysium-developers] Disk block server and block sizes

[Kasper V. L. <ve...@da...>]

Adam Langley wrote:
> The buffer cache not only fills up, it dynamically resizes. If there is any
> free memory the buffer cache should eat it, and as soon as their is any
> memory pressure the BC should shrink.
>
> I think (if we allow processes to map the BC) that we possibly must walk
> page tables and remove mappings (Ouch!)

It should be impossible to map the entire BC - you should only be
allowed to map disk blocks that you can prove you have access  to.

We might consider keeping a reverse page mapping function in the kernel
(should be accessible read-only from user-space). Given a physical page,
p,  the function should return the set of virtual addresses - and
corresponding address spaces - that map p. 

/Kasper 

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Kasper Verdich Lund, Computer Science Department, Aarhus University
Office: 34P.218              | Phone: (+45) 8942 5680
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