Re: [PATCH] erofs: add folio order to trace_erofs_read_folio

[Gao Xiang]

Hi Xusheng,

On 2026/6/17 15:16, Zhan Xusheng wrote:
> erofs supports large folios for reads, but the actual folio order
> instantiated in the page cache may be lower due to allocation
> constraints such as memory fragmentation.
>
> trace_erofs_read_folio already receives the folio being read but
> currently records only its index. Add folio_order() to the tracepoint
> so that users can observe the realized folio order and verify the
> effectiveness of large folio reads.
>
> Signed-off-by: Zhan Xusheng <zhanxusheng@xxxxxxxxxx>
> ---
>   include/trace/events/erofs.h | 7 +++++--
>   1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/include/trace/events/erofs.h b/include/trace/events/erofs.h
> index cd0e3fd8c23f..73d3bfd8b673 100644
> --- a/include/trace/events/erofs.h
> +++ b/include/trace/events/erofs.h
> @@ -90,6 +90,7 @@ TRACE_EVENT(erofs_read_folio,
>   		__field(erofs_nid_t,    nid     )
>   		__field(int,		dir	)
>   		__field(pgoff_t,	index	)
> +		__field(unsigned int,	order	)
>   		__field(int,		uptodate)
>   		__field(bool,		raw	)
>   	),
> @@ -99,15 +100,17 @@ TRACE_EVENT(erofs_read_folio,
>   		__entry->nid	= EROFS_I(inode)->nid;
>   		__entry->dir	= S_ISDIR(inode->i_mode);
>   		__entry->index	= folio->index;
> +		__entry->order	= folio_order(folio);
>   		__entry->uptodate = folio_test_uptodate(folio);

I guess uptodate is unneeded, it should be always !uptodate.

>   		__entry->raw = raw;
>   	),
>   
> -	TP_printk("dev = (%d,%d), nid = %llu, %s, index = %lu, uptodate = %d "
> -		"raw = %d",
> +	TP_printk("dev = (%d,%d), nid = %llu, %s, index = %lu, order = %u, "
> +		"uptodate = %d raw = %d",

Just a nit, can we rearrange the message into one line
in this patch?

i.e.
	"dev = (%d,%d), nid = %llu, %s, index = %lu, order = %u, raw = %d",

Thanks,
Gao Xiang

>   		show_dev_nid(__entry),
>   		show_file_type(__entry->dir),
>   		(unsigned long)__entry->index,
> +		__entry->order,
>   		__entry->uptodate,
>   		__entry->raw)
>   );