I had this issue too on AWS. In my case, it was the udev rule for vm-hotadd and the fix as mentioned previously basically came down to "touch /etc/udev/rules.d/40-vm- hotadd.rules" which effectively disables the /lib/udev/rules.d/40-vm- hotadd.rules file (after a reboot).
The udev rule basically seems to only be active for Xen or Hyper-V and while it seems the Hyper-V stuff was also present in previous versions, the Xen stuff seems to be introduced in 15.10 or newer. So if you're seeing this issue on anything running on Xen, including AWS, try: touch /etc/udev/rules.d/40-vm-hotadd.rules reboot This is probably a bug in Xen or a bug in the kernel. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1518457 Title: kswapd0 100% CPU usage Status in Linux: Unknown Status in linux package in Ubuntu: Confirmed Bug description: As per bug 721896 and various others: I'm on an AWS t2.micro instance (Xeon E5-2670, 991MiB of memory). Occasionally (about once a day), kswapd0 falls into a busy loop and spins on 100% CPU usage indefinitely. This can be provoked by copying/writing large files (e.g. dding a 256MB file), but it happens occasionally otherwise. System memory usage (not including buffers/caches) currently sits at 36%, which is typical[1]. Initially I had no swap space configured; I've since tried enabling a 256MB swap file, but the problem continues to occur and no swap space is used. The system can be recovered with `echo 1 > /proc/sys/vm/drop_caches`. Happy to provide further information/take further debugging actions. [1] Full output from `free`: total used free shared buffers cached Mem: 1014936 483448 531488 28556 9756 112700 -/+ buffers/cache: 360992 653944 Swap: 262140 0 262140 ProblemType: Bug DistroRelease: Ubuntu 15.10 Package: linux-image-4.2.0-18-generic 4.2.0-18.22 ProcVersionSignature: Ubuntu 4.2.0-18.22-generic 4.2.3 Uname: Linux 4.2.0-18-generic x86_64 AlsaDevices: total 0 crw-rw---- 1 root audio 116, 1 Nov 19 19:40 seq crw-rw---- 1 root audio 116, 33 Nov 19 19:40 timer AplayDevices: Error: [Errno 2] No such file or directory: 'aplay' ApportVersion: 2.19.1-0ubuntu5 Architecture: amd64 ArecordDevices: Error: [Errno 2] No such file or directory: 'arecord' AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/seq', '/dev/snd/timer'] failed with exit code 1: CRDA: N/A Date: Fri Nov 20 20:44:30 2015 Ec2AMI: ami-1c552a76 Ec2AMIManifest: (unknown) Ec2AvailabilityZone: us-east-1d Ec2InstanceType: t2.micro Ec2Kernel: unavailable Ec2Ramdisk: unavailable IwConfig: Error: [Errno 2] No such file or directory: 'iwconfig' Lsusb: Error: command ['lsusb'] failed with exit code 1: unable to initialize libusb: -99 MachineType: Xen HVM domU PciMultimedia: ProcEnviron: TERM=screen PATH=(custom, no user) LANG=en_US.UTF-8 SHELL=/bin/bash ProcFB: 0 xen ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.2.0-18-generic root=UUID=35bc01f4-4602-4823-976e-508edef899df ro console=tty1 console=ttyS0 net.ifnames=0 RelatedPackageVersions: linux-restricted-modules-4.2.0-18-generic N/A linux-backports-modules-4.2.0-18-generic N/A linux-firmware N/A RfKill: Error: [Errno 2] No such file or directory: 'rfkill' SourcePackage: linux UdevLog: Error: [Errno 2] No such file or directory: '/var/log/udev' UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 05/06/2015 dmi.bios.vendor: Xen dmi.bios.version: 4.2.amazon dmi.chassis.type: 1 dmi.chassis.vendor: Xen dmi.modalias: dmi:bvnXen:bvr4.2.amazon:bd05/06/2015:svnXen:pnHVMdomU:pvr4.2.amazon:cvnXen:ct1:cvr: dmi.product.name: HVM domU dmi.product.version: 4.2.amazon dmi.sys.vendor: Xen To manage notifications about this bug go to: https://bugs.launchpad.net/linux/+bug/1518457/+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
