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SubjectRe: copy_from_user / copy_to_user with no swap space
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mfbaustx <mfbaustx@gmail.com> wrote:
> >>> No. Your code may be only partially paged into RAM.
> >>> The same can happen for any mmaped data.

> That's what I thought I read. But then my question is: with
> on-demand paging, is it possible to have two processes partially
> paged?

Why shouldn't they be? The whole idea is having just /parts/ (hopefully the
ones in active use) in memory.

> Surely, it MUST be the case that any processes with
> overlapping logical address spaces must be paged coherently.

I don't know what this is supposed to mean...

> So,
> while on-demand "paging-in" allows for partial paging of a process,
> is it the case that, on a context switch, the user-space PTE's are
> completely erased (so that you get page-faults and can then on-demand
> page them in...)?

Each process has its own page tables, they don't get in each others
hair. And the page tables precisely manage making several processes get
access to the /same/ logical addresses, but at /different/ physical
addresses.
--
Dr. Horst H. von Brand User #22616 counter.li.org
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