Re: RFC: pageable kernel-segments

From: Albert D. Cahalan (acahalan@cs.uml.edu)
Date: Tue Apr 17 2001 - 18:58:05 EST


H. Peter Anvin writes:
> By author: "Heusden, Folkert van" <f.v.heusden@ftr.nl>

>> Would anyone be intrested (besides me) in a kernel which can page
...
>> Certain parts of drivers could get the __pageable prefix or so

> VMS does this. It at least used to have a great tendency to crash
> itself, because it swapped out something that was called from a driver
> that was called by the swapper -- resulting in deadlock. You need
> iron discipline for this to work right in all circumstances.
>
> Second, it makes it quite hard to know what operations can cause a
> task to sleep, since any reference to paged-out memory can require a
> page-in and the associated schedule. You almost need pointer
> annotation in order for this to be safe.

It wouldn't be nearly so dangerous to page from compressed
data in memory. The memory could be ROM.

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This archive was generated by hypermail 2b29 : Mon Apr 23 2001 - 21:00:24 EST