On 8/20/19 7:14 AM, Song Liu wrote: >> *But*, that shouldn't get hit on a Skylake CPU since those have PCIDs >> and shouldn't have a global kernel image. Could you confirm whether >> PCIDs are supported on this CPU? > Yes, pcid is listed in /proc/cpuinfo. So what's going on? Could you confirm exactly which pti_clone_pgtable() is causing you problems? Do you have a theory as to why this manifests as a performance problem rather than a functional one? A diff of these: /sys/kernel/debug/page_tables/current_user /sys/kernel/debug/page_tables/current_kernel before and after your patch might be helpful.
