On 02/11/2015 08:36, Liang Li wrote: > The patch 3ea3b7fa9af067982f34b of kvm introduces a lazy collapsing > of small sptes into large sptes mechanism, which intend to solve the > performance drop issue if live migration fails or is canceled. The > rmap will be scanned in the KVM_SET_USER_MEMORY_REGION ioctl context > when dirty logging is stopped so as to drop the small sptes, scanning > the rmap and drop the small sptes is a time consuming operation which > will take dozens of milliseconds, the actual time depends on VM's > memory size. For a VM with 8GB RAM, it will take about 30ms.
I'm okay with these patches. Juan, can they be included in 2.5? However, the KVM patch is a regression too. Wanpeng, can you look into doing the collapsing from a work item? Thanks, Paolo
