Re: [PATCH v4 10/12] khugepaged: improve tracepoints for mTHP orders

[Baolin Wang <baolin.wang@linux.alibaba.com>]

On 2025/4/17 08:02, Nico Pache wrote:
> Add the order to the tracepoints to give better insight into what order
> is being operated at for khugepaged.
> 
> Signed-off-by: Nico Pache <npache@redhat.com>

LGTM.
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>

> ---
>   include/trace/events/huge_memory.h | 34 +++++++++++++++++++-----------
>   mm/khugepaged.c                    | 10 +++++----
>   2 files changed, 28 insertions(+), 16 deletions(-)
> 
> diff --git a/include/trace/events/huge_memory.h b/include/trace/events/huge_memory.h
> index 9d5c00b0285c..ea2fe20a39f5 100644
> --- a/include/trace/events/huge_memory.h
> +++ b/include/trace/events/huge_memory.h
> @@ -92,34 +92,37 @@ TRACE_EVENT(mm_khugepaged_scan_pmd,
>   
>   TRACE_EVENT(mm_collapse_huge_page,
>   
> -	TP_PROTO(struct mm_struct *mm, int isolated, int status),
> +	TP_PROTO(struct mm_struct *mm, int isolated, int status, int order),
>   
> -	TP_ARGS(mm, isolated, status),
> +	TP_ARGS(mm, isolated, status, order),
>   
>   	TP_STRUCT__entry(
>   		__field(struct mm_struct *, mm)
>   		__field(int, isolated)
>   		__field(int, status)
> +		__field(int, order)
>   	),
>   
>   	TP_fast_assign(
>   		__entry->mm = mm;
>   		__entry->isolated = isolated;
>   		__entry->status = status;
> +		__entry->order = order;
>   	),
>   
> -	TP_printk("mm=%p, isolated=%d, status=%s",
> +	TP_printk("mm=%p, isolated=%d, status=%s order=%d",
>   		__entry->mm,
>   		__entry->isolated,
> -		__print_symbolic(__entry->status, SCAN_STATUS))
> +		__print_symbolic(__entry->status, SCAN_STATUS),
> +		__entry->order)
>   );
>   
>   TRACE_EVENT(mm_collapse_huge_page_isolate,
>   
>   	TP_PROTO(struct page *page, int none_or_zero,
> -		 int referenced, bool  writable, int status),
> +		 int referenced, bool  writable, int status, int order),
>   
> -	TP_ARGS(page, none_or_zero, referenced, writable, status),
> +	TP_ARGS(page, none_or_zero, referenced, writable, status, order),
>   
>   	TP_STRUCT__entry(
>   		__field(unsigned long, pfn)
> @@ -127,6 +130,7 @@ TRACE_EVENT(mm_collapse_huge_page_isolate,
>   		__field(int, referenced)
>   		__field(bool, writable)
>   		__field(int, status)
> +		__field(int, order)
>   	),
>   
>   	TP_fast_assign(
> @@ -135,27 +139,31 @@ TRACE_EVENT(mm_collapse_huge_page_isolate,
>   		__entry->referenced = referenced;
>   		__entry->writable = writable;
>   		__entry->status = status;
> +		__entry->order = order;
>   	),
>   
> -	TP_printk("scan_pfn=0x%lx, none_or_zero=%d, referenced=%d, writable=%d, status=%s",
> +	TP_printk("scan_pfn=0x%lx, none_or_zero=%d, referenced=%d, writable=%d, status=%s order=%d",
>   		__entry->pfn,
>   		__entry->none_or_zero,
>   		__entry->referenced,
>   		__entry->writable,
> -		__print_symbolic(__entry->status, SCAN_STATUS))
> +		__print_symbolic(__entry->status, SCAN_STATUS),
> +		__entry->order)
>   );
>   
>   TRACE_EVENT(mm_collapse_huge_page_swapin,
>   
> -	TP_PROTO(struct mm_struct *mm, int swapped_in, int referenced, int ret),
> +	TP_PROTO(struct mm_struct *mm, int swapped_in, int referenced, int ret,
> +			int order),
>   
> -	TP_ARGS(mm, swapped_in, referenced, ret),
> +	TP_ARGS(mm, swapped_in, referenced, ret, order),
>   
>   	TP_STRUCT__entry(
>   		__field(struct mm_struct *, mm)
>   		__field(int, swapped_in)
>   		__field(int, referenced)
>   		__field(int, ret)
> +		__field(int, order)
>   	),
>   
>   	TP_fast_assign(
> @@ -163,13 +171,15 @@ TRACE_EVENT(mm_collapse_huge_page_swapin,
>   		__entry->swapped_in = swapped_in;
>   		__entry->referenced = referenced;
>   		__entry->ret = ret;
> +		__entry->order = order;
>   	),
>   
> -	TP_printk("mm=%p, swapped_in=%d, referenced=%d, ret=%d",
> +	TP_printk("mm=%p, swapped_in=%d, referenced=%d, ret=%d, order=%d",
>   		__entry->mm,
>   		__entry->swapped_in,
>   		__entry->referenced,
> -		__entry->ret)
> +		__entry->ret,
> +		__entry->order)
>   );
>   
>   TRACE_EVENT(mm_khugepaged_scan_file,
> diff --git a/mm/khugepaged.c b/mm/khugepaged.c
> index 738dd9c5751d..67da0950b833 100644
> --- a/mm/khugepaged.c
> +++ b/mm/khugepaged.c
> @@ -721,13 +721,14 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma,
>   	} else {
>   		result = SCAN_SUCCEED;
>   		trace_mm_collapse_huge_page_isolate(&folio->page, none_or_zero,
> -						    referenced, writable, result);
> +						    referenced, writable, result,
> +						    order);
>   		return result;
>   	}
>   out:
>   	release_pte_pages(pte, _pte, compound_pagelist);
>   	trace_mm_collapse_huge_page_isolate(&folio->page, none_or_zero,
> -					    referenced, writable, result);
> +					    referenced, writable, result, order);
>   	return result;
>   }
>   
> @@ -1097,7 +1098,8 @@ static int __collapse_huge_page_swapin(struct mm_struct *mm,
>   
>   	result = SCAN_SUCCEED;
>   out:
> -	trace_mm_collapse_huge_page_swapin(mm, swapped_in, referenced, result);
> +	trace_mm_collapse_huge_page_swapin(mm, swapped_in, referenced, result,
> +						order);
>   	return result;
>   }
>   
> @@ -1318,7 +1320,7 @@ static int collapse_huge_page(struct mm_struct *mm, unsigned long address,
>   	*mmap_locked = false;
>   	if (folio)
>   		folio_put(folio);
> -	trace_mm_collapse_huge_page(mm, result == SCAN_SUCCEED, result);
> +	trace_mm_collapse_huge_page(mm, result == SCAN_SUCCEED, result, order);
>   	return result;
>   }
>