Linux 7.4 makes hot-adding memory to VMs and CXL up to 81% faster

A patch series by Yuan Liu (Intel), queued in mm/core.git ahead of the Linux 7.4 merge window, replaces page-by-page zone scans with an optimized contiguity check. Measured: up to 81% less time to hot-add memory to a VM and 75% to hot-remove it, with Samsung also reporting CXL gains.