TLBmiss Counter

This linux kernel module was created as part of the course Topics in Operating Systems (CS730A) Spring Semester - 2019, instructed by Prof. Debadatta Mishra.

A linux kernel module to count number of TLB misses encountered during program execution. The module is also extended to handle Page Table Isolation (a Meltdown-attack mitigation) and count the number of unused, read-only and written pages. The base code (fault_hook.patch) was provided.

Build Instruction

• Patch your kernel with fault_hook.patch.

 cd module && make       # build the module

 sudo insmod memtrack.ko		#insert the module into the kernel

• The module has the following sysfs variables (/sys/kernel/memtrack):
  • command: 0 to count TLB misses w/o PTI. 1 to count TLB misses w PTI. 2 to count read-only, unused and write pages.
  • tlb_misses: Total number of TLB misses
  • unused: Number of unused pages
  • readwss: Number of read-only pages
  • writewss: Number of pages that were written to