Add some trace events for the page allocator

Mel Gorman has posted series of patches to add trace events for page allocator:


http://marc.info/?l=linux-kernel&m=124991900725530&w=2


Here is How I tested out those patches:

1, make menuconfig as below:

kernel hacking -> Tracers

.config - Linux Kernel v2.6.31-rc5 Configuration
─────────────────────────────────────────────────────────────────────────────────────────────────────
┌─────────────────────────────────────────── Tracers ────────────────────────────────────────────┐
│ Arrow keys navigate the menu. selects submenus --->. Highlighted letters are │
│ hotkeys. Pressing includes, excludes, modularizes features. Press to │
│ exit, for Help, for Search. Legend: [*] built-in [ ] excluded module < > │
│ module capable │
│ ┌────────────────────────────────────────────────────────────────────────────────────────────┐ │
│ │ --- Tracers │ │
│ │ [*] Kernel Function Tracer │ │
│ │ [*] Kernel Function Graph Tracer │ │
│ │ [ ] Interrupts-off Latency Tracer │ │
│ │ [ ] Sysprof Tracer │ │
│ │ [ ] Scheduling Latency Tracer │ │
│ │ [*] Trace syscalls │ │
│ │ [ ] Trace boot initcalls │ │
│ │ Branch Profiling (No branch profiling) ---> │ │
│ │ [ ] Trace power consumption behavior │ │
│ │ [ ] Trace max stack │ │
│ │ [*] Trace SLAB allocations │ │
│ │ [ ] Trace workqueues │ │
│ │ [*] Support for tracing block io actions │ │
│ │ [*] enable/disable ftrace tracepoints dynamically │ │
│ │ [*] Kernel function profiler │ │
│ │ [ ] Perform a startup test on ftrace │ │
│ │ [*] Memory mapped IO tracing │ │
│ │ < > Test module for mmiotrace │ │
│ │ < > Ring buffer benchmark stress tester │ │
│ │ │ │
│ └────────────────────────────────────────────────────────────────────────────────────────────┘ │

2, read Documentation/trace/ftrace.txt and add line below in /etc/fstab:

debugfs /sys/kernel/debug debugfs defaults 0 0

3, apply the series of patches in order as git am series of patches

4, enable page allocator tracing events with:

#for i in `find /sys/kernel/debug/tracing/events -name "enable" | grep mm_`; do echo 1 > $i; done

5, run post-process script to get the page allocator events tracing data:

trace-pagealloc-postprocess.pl < /sys/kernel/debug/tracing/trace_pipe

We could use perf user tools under tools/perf/ to enable the page allocator trace events and track events data. read more in Documentation/trace/tracepoint-analysis.txt