pfaults.stp fix (for 2.6.13 and beyond)

[William Cohen]

Badari Pulavarty wrote:
> Hi,
> 
> handle_mm_fault() became a inline function now (2.6.13 & beyond). 
> So pfaults.stp should use __handle_mm_fault() instead.
> 
> Thanks,
> Badari
> 
> [root@elm3b23 systemtap.samples]# stap -g pfaults.stp
> semantic error: no match for probe point
>          while: resolving probe point kernel.function("handle_mm_fault")
> semantic error: no match for probe point
>          while: resolving probe point kernel.function
> ("handle_mm_fault").return
> Pass 2: analysis failed.  Try again with '-v' (verbose) option.

The number for the various types of faults will also need to be 
adjusted. Looking at 2.6.13-1.1526 kernel used in FC4.

linux-2.6.13/include/linux/mm.h has:

#define VM_FAULT_OOM    0x00
#define VM_FAULT_SIGBUS 0x01
#define VM_FAULT_MINOR  0x02
#define VM_FAULT_MAJOR  0x03

I noticed this because of the large number of major faults without any 
minor faults recorded. However, using the numbers above I see values 
that look more reasonable for minor faults, but I don't see any major 
faults counted when I was playing around with this.

-Will

> 
> 
> 
> 
> 
> ------------------------------------------------------------------------
> 
> --- tests/testsuite/systemtap.samples/pfaults.stp	2005-10-05 08:13:29.000000000 -0700
> +++ tests.new/testsuite/systemtap.samples/pfaults.stp	2005-10-05 08:11:27.000000000 -0700
> @@ -2,7 +2,7 @@
>  
>  global pidnames, faults, fault_types
>  
> -probe kernel.function("handle_mm_fault") {
> +probe kernel.function("__handle_mm_fault") {
>  
>     # Maintain a pid-to-execname mapping.  This logic should get transplanted
>     # into a tapset script that is automatically included upon reference to
> @@ -15,7 +15,7 @@ probe kernel.function("handle_mm_fault")
>  # (needed only until bug 1132 supports $retvalue)
>  function get_retvalue:long () %{ THIS->__retvalue = fetch_register(0); %}
>  
> -probe kernel.function("handle_mm_fault").return {
> +probe kernel.function("__handle_mm_fault").return {
>    fault_types [pid(), get_retvalue()] ++
>  }
>