Re: What exactly is the need to have swappable and non swappable pages

Ulrich Eckhardt wrote:
MAx wrote:

What is the need of having non swappable pages?


You can't put the code that handles swapping into swappable pages itself.
Also, you shouldn't put code that needs to fulfill some realtime
requirements into swappable pages if swapping in would be too slow.

Also, you may have some external entity (e.g. a video card) which requires continuous access to these pages.

What is the disadvantage of *NOT* having non swappable pages?

You will not be able to do those things that you need the non swappable pages for:
- Swap pages in and out
- Have fast access to certain data
- Have external access to certain data

Is there any problem if Non Swappable pages were to be made
swappable...?

See above.

Some security-sensitive applications put private data into non-swappable
pages in order to not have them swapped to an unencrypted swap file.

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Josef Möllers (Pinguinpfleger bei FSC)
If failure had no penalty success would not be a prize (T. Pratchett)
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