perf record to a process and the report says that 92% of the time is in kernel function
change_protection_range (and next 5% in
vm_normal_page). The program is using a lot of memory, and should be decompressing the contents to disk.
sar shows relatively low CPU usage, iowait, steal etc.
What does this tell me about the hotspot? It looks like something related to making VM pages writeable?