Tracking vm activity

[William Cohen]

Stone, Joshua I wrote:
> William Cohen wrote:
>> I am playing around with getting information about page faults and I 
>> noticed that there is a probe alias for the entry for the pagefault 
>> code. However, there is no matching probe point for the return. It is 
>> useful to look at the return value to determine what kind of page 
>> fault occurred (major or minor). The attached patch provides a similar 
>> probe point for the return point. any comments on the patch?
> 
> I see that you committed it, and added a variable for the return value 
> (fault_type).  Could you elaborate in the documentation what the 
> possible types are (major, minor) and their values?
> 
> Thanks,
> 
> Josh

Hi Josh,

Is this suitable for comment for vm.pagefault.return? If suitable, I will go 
ahead and check it in.


/* probe vm.pagefault.return
  *
  *  Records type of fault that occurred.
  *
  * Context:
  *  The process which triggered the fault.
  *
  * Argumentss:
  *  fault_type - type of fault
  *	VM_FAULT_OOM	0	out of memory
  *	VM_FAULT_SIGBUS	1	if not oom, minor, or major fault, this val
  *	VM_FAULT_MINOR	2	no blocking operation to handle fault
  *	VM_FAULT_MAJOR	3	required blocking operation to handle fault
  */

-Will