Re: [PATCH v4 23/26] mm/x86: Use general page fault accounting

[Dave Hansen]

On 6/30/20 1:46 PM, Peter Xu wrote:
> Use the general page fault accounting by passing regs into handle_mm_fault().
...
> -	/*
> -	 * Major/minor page fault accounting. If any of the events
> -	 * returned VM_FAULT_MAJOR, we account it as a major fault.
> -	 */
> -	if (major) {
> -		tsk->maj_flt++;
> -		perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, regs, address);
> -	} else {
> -		tsk->min_flt++;
> -		perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, regs, address);
> -	}
> -
>  	check_v8086_mode(regs, address, tsk);
>  }

I did a quick grep and it wasn't obvious to me how
PERF_COUNT_SW_PAGE_FAULTS_MIN/MAJ get bumped in the handle_mm_fault() path.

Are you sure they get set?