[SOLVED] Swap and hibernation

SlowCoder · 10-07-2021, 09:59 AM

When a machine goes into hibernation, and stores RAM contents into swap, is the entirety of RAM stored, or just the RAM currently utilized by open processes?

business_kid · 10-07-2021, 10:09 AM

It would appear to be the latter, because I currently have 6G of ram and 5G of swap.

boughtonp · 10-07-2021, 10:21 AM

Quote:

Originally Posted by https://www.kernel.org/doc/html/latest/admin-guide/pm/sleep-states.html

image_size

This file controls the size of hibernation images.

It can be written a string representing a non-negative integer that will be used as a best-effort upper limit of the image size, in bytes. The hibernation core will do its best to ensure that the image size will not exceed that number, but if that turns out to be impossible to achieve, a hibernation image will still be created and its size will be as small as possible. In particular, writing ‘0’ to this file causes the size of hibernation images to be minimum.

Reading from it returns the current image size limit, which is set to around 2/5 of the available RAM size by default.

sundialsvcs · 10-08-2021, 10:02 AM

Hibernate stores only the memory contents that are in use and that cannot simply be re-created when the system resumes.

SlowCoder · 10-08-2021, 02:23 PM

Thank you all.

sundialsvcs · 10-08-2021, 02:43 PM

Of course, one of the very nicest things about open-source Linux is that you can actually look at the hibernate/resume code and see for yourself exactly what it does.