** Description changed: [Impact] The 5.8 kernel (groovy) is not still 100% reliable with hibernation, especially on the Xen instance type. However, re-aligning the config options as much as possible with the 5.4 kernel (focal) allows to hibernate and resume with a success rate close to 100% (according to our tests on the AWS cloud). [Test case] - - spin up an AWS instance (for example a c4.8xlarge instance type) - - run a memory stress test - - hibernate - - resume - - verify that the system has been resumed correctly and the memory stress test is still running + - spin up an AWS instance (for example a c4.8xlarge instance type) + - run a memory stress test + - hibernate + - resume + - verify that the system has been resumed correctly and the memory stress test is still running [Fix] - Identify the minimum subset of config changes that we need to apply to - the 5.8 kernel to make hibernation as reliable as 5.4. + The following fixes must be applied to improve hibernation/resume + reliability: + + - disable CONFIG_SUSPEND (suspend to memory is not supported in AWS and + it can introduce a deadlock condition with the Xen hibernation layer) + - make sure CONFIG_DMA_CMA is disabled (this introduces another + deadlock condition with Xen) + - disable CONFIG_FB_HYPERV: this would enable CONFIG_DMA_CMA and we + dont' want that (to prevent the Xen deadlock); moreover this driver + is not needed at all in the AWS environment + - disable CONFIG_XEN_FBDEV_FRONTEND: this is also not required in the + AWS environement and it has the potential of breaking hibernation + - disable CONFIG_INPUT_XEN_KBDDEV_FRONTEND + - compile xen-netfront as module + - disable CONFIG_XEN_BALLOON + - remove all sound-related modules (not really needed in the AWS cloud, + they were also disabled on 5.4) [Regression potential] - Still need to be evaluated exactly, probably we will have to apply only - .config changes, so regression potential will be minimal. + These are all .config changes. With these changes we are basically + re-aligning with the previous 5.4 settings and we have experimentally + verified (tests) that these changes are increasing the success rate of + hibernation. So the regression potential is minimal.
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1902926 Title: aws: improve hibernation reliability in groovy To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-aws/+bug/1902926/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
