Kernel dynamic memory analysis

This page has notes and results from the project Kernel dynamic memory allocation tracking and reduction

[This page is fairly random at the moment...]

Instrumentation

• slab_accounting patches
  • use __builtin_return_address(0) to record the address of the caller
    • this same mechanism used by kmem events
    • if gcc decides to inline automatically, you get the wrong call site
      • can disable automatic inlinining with a compiler flag
  • starts from very first allocation

• kmem events
  • does not start until ftrace system is initialized, after some allocations are already performed

Reporting

• extracting data to host
  • tool for extraction (perf?)
• post-processing the data
  • grouping allocations (assigning to different subsystems, processes, or functional areas)
    • idea to post-process kmem events and correlate with */built-in.o
  • reporting on wasted bytes
  • reporting on memory fragmentation

Visualization

• • possible use of treemap to visualize the data

Mainline status

• is anything added to mainline via this project?

Recommendations for reductions

???