Automated tests

Posted Mar 10, 2021 2:52 UTC (Wed) by Cyberax (✭ supporter ✭, #52523)
In reply to: Automated tests by corbet
Parent article: Linux 5.12's very bad, double ungood day

> One could certainly write an automated test to catch this, but it would not be easy.
I was one of people responsible for getting EC2 instances to hibernate. We used files for hibernation and actually found that the kernel had been broken for YEARS with file hibernation (it required a reboot for the hibernation target setting to take effect).

We also had a test for this very issue. It created an EC2 instance with a small disk (~2Gb) and limited RAM (512Mb). The test program created a swap file and then filled the disk to capacity with pseudo-random numbers (by creating a file and writing to it). It then allocated enough pseudo-random data to swap out at least some of it.

Then hibernate, thaw, and checksum the disk and the data in RAM to check for corruption.

The tests ran in about 2 minutes.

Automated tests

Posted Mar 10, 2021 22:12 UTC (Wed) by sjj (guest, #2020) [Link] (1 responses)

Interesting, I never thought about hibernation in AWS. I haven’t thought about hibernation in years, since it was the unreliable thing you had to do on laptops of the day.

Curious what the use case for it in AWS is.

Hibernation

Posted Mar 10, 2021 22:18 UTC (Wed) by corbet (editor, #1) [Link]

That work, and the use case behind it, were discussed in this OSPM article from last May.