Re: [PATCH v2 6/6] mm: Print hashed address of struct page

[John Hubbard <jhubbard@nvidia.com>]

On 2020-07-09 13:21, Matthew Wilcox (Oracle) wrote:
> The actual address of the struct page isn't particularly helpful,
> while the hashed address helps match with other messages elsewhere.
> Add the PFN that the page refers to in order to help diagnose problems
> where the page is improperly aligned for the purpose.
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> ---
>   mm/debug.c | 8 ++++----
>   1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/mm/debug.c b/mm/debug.c
> index 60347d0d7609..033f04ffc398 100644
> --- a/mm/debug.c
> +++ b/mm/debug.c
> @@ -89,17 +89,17 @@ void __dump_page(struct page *page, const char *reason)
>   	 */
>   	mapcount = PageSlab(head) ? 0 : page_mapcount(page);
>   
> -	pr_warn("page:%px refcount:%d mapcount:%d mapping:%p index:%#lx\n",
> +	pr_warn("page:%p refcount:%d mapcount:%d mapping:%p index:%#lx pfn:%#lx\n",
>   			page, page_ref_count(head), mapcount, mapping,
> -			page_to_pgoff(page));
> +			page_to_pgoff(page), page_to_pfn(page));
>   	if (compound) {
>   		if (hpage_pincount_available(page)) {
> -			pr_warn("head:%px order:%u compound_mapcount:%d compound_pincount:%d\n",
> +			pr_warn("head:%p order:%u compound_mapcount:%d compound_pincount:%d\n",
>   					head, compound_order(head),
>   					compound_mapcount(head),
>   					compound_pincount(head));
>   		} else {
> -			pr_warn("head:%px order:%u compound_mapcount:%d\n",
> +			pr_warn("head:%p order:%u compound_mapcount:%d\n",
>   					head, compound_order(head),
>   					compound_mapcount(head));
>   		}
> 

Seems reasonable. The first output line is getting long again, but it's still
OK-ish.

     Reviewed-by: John Hubbard <jhubbard@nvidia.com>


thanks,
-- 
John Hubbard
NVIDIA