Re: [PATCH 2/2] mm/page_alloc: replace custom bad page ratelimiting logic

["Lorenzo Stoakes (ARM)" <ljs@kernel.org>]

On Tue, Aug 11, 2026 at 06:21:56PM +0100, Pedro Falcato wrote:
> The current logic (allow up to $BURST prints per minute) can be entirely
> replaced by the generic version in lib/ratelimit.c, used around the kernel.
>
> Do so. The only functional difference should be that the new logs will
> read something like:
>
> KERN_WARNING "bad_page: %d callbacks suppressed\n", ...
>
> But that should be fine enough.
>
> Signed-off-by: Pedro Falcato <pfalcato@suse.de>

LGTM so:

Reviewed-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>

> ---
>  mm/page_alloc.c | 28 +++++-----------------------
>  1 file changed, 5 insertions(+), 23 deletions(-)
>
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 12fac9084c48..9ccfd87bc273 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -613,31 +613,13 @@ static inline bool __maybe_unused bad_range(struct zone *zone, struct page *page
>  }
>  #endif
>
> +/* Allow a burst of 60 reports per minute */
> +static DEFINE_RATELIMIT_STATE(bad_page_ratelimit, 60 * HZ, 60);
> +
>  static void bad_page(struct page *page, const char *reason)
>  {
> -	static unsigned long resume;
> -	static unsigned long nr_shown;
> -	static unsigned long nr_unshown;
> -
> -	/*
> -	 * Allow a burst of 60 reports, then keep quiet for that minute;
> -	 * or allow a steady drip of one report per second.
> -	 */
> -	if (nr_shown == 60) {
> -		if (time_before(jiffies, resume)) {
> -			nr_unshown++;
> -			goto out;
> -		}
> -		if (nr_unshown) {
> -			pr_alert(
> -			      "BUG: Bad page state: %lu messages suppressed\n",
> -				nr_unshown);
> -			nr_unshown = 0;
> -		}
> -		nr_shown = 0;
> -	}
> -	if (nr_shown++ == 0)
> -		resume = jiffies + 60 * HZ;
> +	if (!__ratelimit(&bad_page_ratelimit))
> +		goto out;
>
>  	pr_alert("BUG: Bad page state in process %s  pfn:%05lx\n",
>  		current->comm, page_to_pfn(page));
> --
> 2.55.0
>

--
Cheers, Lorenzo