@dgilbert-h / Dr. David Alan Gilbert Thanks for your answer. b) Mounted/used block devices: NAME MOUNTPOINT TYPE FSTYPE sda disk crypto_LUKS └─Data1 crypt zfs_member ├─sdb5 / part ext4 └─sdb6 /boot part vfat sdd disk crypto_LUKS └─Data2 crypt zfs_member ZFS file system for extra space, also ZFS is the reason I'm not running the latest kernel...
a) $ free total used free shared buff/cache available Mem: 16379476 7879216 1867196 188180 6633064 3587620 Swap: 0 0 0 $ qemu.sh -m 10240 && echo success || echo failed qemu-system-x86_64: cannot set up guest memory 'pc.ram': Cannot allocate memory failed $ sudo sh -c 'echo 1 > /proc/sys/vm/overcommit_memory' $ qemu.sh -m 10240 && echo success || echo failed success So setting /proc/sys/vm/overcommit_memory to 1 works, so I guess I'm gonna need to execute sudo sh -c 'echo 1 > /proc/sys/vm/overcommit_memory' at start of my qemu.sh script instead of the 'drop_caches' part. I still think the kernel should do whatever function overcommit_memory is for automatically, bit it seams to be the fault of the kernel of my distribution then, thanks for your help. -- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1609968 Title: "cannot set up guest memory" b/c no automatic clearing of Linux' cache Status in QEMU: New Bug description: Version: qemu-2.6.0-1 Kernel: 4.4.13-1-MANJARO Full script (shouldn't matter though): https://pastebin.com/Hp24PWNE Problem: When host has been up and used for a while cache has been filled as much that guest can't be started without droping caches. Expected behavior: Qemu should be able to request as much Memory as it needs and cause Linux to drop cache pages if needed. A user shouldn't be required to have to come to this conclusion and having to drop caches to start Qemu with the required amount of memory. My fix: Following command (as root) required before qemu start: # sync && echo 3 > /proc/sys/vm/drop_caches Example: $ sudo qemu.sh -m 10240 && echo success || echo failed qemu-system-x86_64: cannot set up guest memory 'pc.ram': Cannot allocate memory failed $ free total used free shared buff/cache available Mem: 16379476 9126884 3462688 148480 3789904 5123572 Swap: 0 0 0 $ sudo sh -c 'sync && echo 3 > /proc/sys/vm/drop_caches' $ free total used free shared buff/cache available Mem: 16379476 1694528 14106552 149772 578396 14256428 Swap: 0 0 0 $ sudo qemu.sh -m 10240 && echo success || echo failed success To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1609968/+subscriptions