On Wed, Sep 7, 2022 at 7:45 AM Zach O'Keefe <zokeefe@xxxxxxxxxx> wrote:
>
> Add huge_memory:trace_mm_khugepaged_scan_file tracepoint to
> hpage_collapse_scan_file() analogously to hpage_collapse_scan_pmd().
> While this change is targeted at debugging MADV_COLLAPSE pathway, the
> "mm_khugepaged" prefix is retained for symmetry with
> huge_memory:trace_mm_khugepaged_scan_pmd, which retains it's legacy name
> to prevent changing kernel ABI as much as possible.
>
> Signed-off-by: Zach O'Keefe <zokeefe@xxxxxxxxxx>
Reviewed-by: Yang Shi <shy828301@xxxxxxxxx>
> ---
> include/trace/events/huge_memory.h | 34 ++++++++++++++++++++++++++++++
> mm/khugepaged.c | 3 ++-
> 2 files changed, 36 insertions(+), 1 deletion(-)
>
> diff --git a/include/trace/events/huge_memory.h b/include/trace/events/huge_memory.h
> index df33453b70fc..935af4947917 100644
> --- a/include/trace/events/huge_memory.h
> +++ b/include/trace/events/huge_memory.h
> @@ -169,5 +169,39 @@ TRACE_EVENT(mm_collapse_huge_page_swapin,
> __entry->ret)
> );
>
> +TRACE_EVENT(mm_khugepaged_scan_file,
> +
> + TP_PROTO(struct mm_struct *mm, struct page *page, const char *filename,
> + int present, int swap, int result),
> +
> + TP_ARGS(mm, page, filename, present, swap, result),
> +
> + TP_STRUCT__entry(
> + __field(struct mm_struct *, mm)
> + __field(unsigned long, pfn)
> + __string(filename, filename)
> + __field(int, present)
> + __field(int, swap)
> + __field(int, result)
> + ),
> +
> + TP_fast_assign(
> + __entry->mm = mm;
> + __entry->pfn = page ? page_to_pfn(page) : -1;
> + __assign_str(filename, filename);
> + __entry->present = present;
> + __entry->swap = swap;
> + __entry->result = result;
> + ),
> +
> + TP_printk("mm=%p, scan_pfn=0x%lx, filename=%s, present=%d, swap=%d, result=%s",
> + __entry->mm,
> + __entry->pfn,
> + __get_str(filename),
> + __entry->present,
> + __entry->swap,
> + __print_symbolic(__entry->result, SCAN_STATUS))
> +);
> +
> #endif /* __HUGE_MEMORY_H */
> #include <trace/define_trace.h>
> diff --git a/mm/khugepaged.c b/mm/khugepaged.c
> index 66457a06b4e7..9325aec25abc 100644
> --- a/mm/khugepaged.c
> +++ b/mm/khugepaged.c
> @@ -2152,7 +2152,8 @@ static int hpage_collapse_scan_file(struct mm_struct *mm, unsigned long addr,
> }
> }
>
> - /* TODO: tracepoints */
> + trace_mm_khugepaged_scan_file(mm, page, file->f_path.dentry->d_iname,
> + present, swap, result);
> return result;
> }
> #else
> --
> 2.37.2.789.g6183377224-goog
>
