The execution time for page fault request handling is performance critical and needs to be monitored. This adds code to sample the execution time of page fault request handling. Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> Link: https://lore.kernel.org/r/20210520031531.712333-1-baolu.lu@linux.intel.com Link: https://lore.kernel.org/r/20210610020115.1637656-17-baolu.lu@linux.intel.com Signed-off-by: Joerg Roedel <jroedel@suse.de>