Hi, I just came across an idea and would like to have feedback if it makes sence or not.
If a VM is started without preallocated memory all memory that has not been written to reads as zeros, right? If a VM with a lot of unwritten memory is migrated or if the memory contains a lot of zeroed out memory (e.g. Windows or Linux guest with page sanitization) all this memory is allocated on the target during live migration. Especially with KSM this leads to the problem that this memory is allocated and might be not available completely as merging of the pages will happen async. Wouldn't it make sense to not send zero pages in the first round where the complete ram is sent (if it is detectable that we are in this stage)? Peter
