** 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 Kernel Packages, which is subscribed to linux-aws in Ubuntu. https://bugs.launchpad.net/bugs/1902926 Title: aws: improve hibernation reliability in groovy Status in linux-aws package in Ubuntu: New Status in linux-aws source package in Groovy: New Bug description: [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 [Fix] 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] 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. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-aws/+bug/1902926/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
