Re: [libvirt] [RFC] support memory reserved feature and optimize mlock guest memory propose

> Il 05/03/2014 09:01, Zhanghailiang ha scritto: >> Hi all： >> >> Currently, we use cgroup(memory) to support memory QoS on KVM >> platform, and use "mlock" on qemu to support "memory reserved". >> >> The "mlock" seems to be not appropriate. >> >> Now qemu "mlock" memory in the main thread, which would lock iothread >> (qemu_mutex_lock_iothread), if the memory size is large, that will >> consume lots of time. >> >> It means whenever we want to set a new 'mlock', the VM would be >> blocked for a while. > > I'm not sure I understand how the mlock-ed memory is used. Are you using a > custom malloc, for example with g_mem_set_vtable? > > Paolo Hi Paolo： Thanks for your reply. As you know qemu has an option "-mlock", I think it has some problems. If we set "-realtime mlock=on", then qemu will mlockall vm's memory, It is a very time consuming action, and it will block the libvirt api until it finished. so I think it is better to do 'mlock' asynchronously, the flow chart can be described like below.

Is it ok? Flow chart: main funciton qmp command "set_ram_minguarantee" | | | | create "mlock" thread change value of lock_ram_size | | | | |------>thread wait<-------------wake up "mlock" thread | | | | | | |-------mlock(lock_ram_zie)