Re: [PATCH v2 03/11] mm/damon/paddr: support addr_unit for DAMOS_PAGEOUT

[Quanmin Yan]

在 2025/8/25 23:12, SeongJae Park 写道:
> On Fri, 22 Aug 2025 17:34:11 +0800 Quanmin Yan <yanquanmin1@xxxxxxxxxx> wrote:
>
> > From: SeongJae Park <sj@xxxxxxxxxx>
> >
> > Add support of addr_unit for DAMOS_PAGEOUT action handling from the
> > DAMOS operation implementation for the physical address space.
> [...]
> > -	return applied * PAGE_SIZE;
> > +	return applied * PAGE_SIZE / addr_unit;
> >   }
> Kernel test robot [1] found this can cause __udivdi3 linking issue.  Andrew,
> could you please add the below attached fixup?
>
> [1] https://lore.kernel.org/oe-kbuild-all/202508241831.EKwdwXZL-lkp@xxxxxxxxx/
>
>
> Thanks,
> SJ
>
> [...]
>
> ==== Attachment 0 (0001-mm-damon-paddr-use-do_div-on-i386-for-damon_pa_pageo.patch) ====
>  From hackermail Thu Jan  1 00:00:00 1970
> From: SeongJae Park <sj@xxxxxxxxxx>
> To: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: SeongJae Park <sj@xxxxxxxxxx>
> Cc: damon@xxxxxxxxxxxxxxx
> Cc: kernel-team@xxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Cc: linux-mm@xxxxxxxxx
> Date: Mon, 25 Aug 2025 07:41:33 -0700
> Subject: [PATCH 1/3] mm/damon/paddr: use do_div() on i386 for damon_pa_pageout()
>           return value
>
> Otherwise, __udidi3 linking problem happens on certain configs.
>
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> Closes: https://lore.kernel.org/oe-kbuild-all/202508241831.EKwdwXZL-lkp@xxxxxxxxx/
> Signed-off-by: SeongJae Park <sj@xxxxxxxxxx>
> ---
>   mm/damon/paddr.c | 14 +++++++++++++-
>   1 file changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c
> index 5fad2f9a99a0..09c87583af6c 100644
> --- a/mm/damon/paddr.c
> +++ b/mm/damon/paddr.c
> @@ -135,6 +135,18 @@ static bool damon_pa_invalid_damos_folio(struct folio *folio, struct damos *s)
>   	return false;
>   }
>   
> +/* convert physical address to core-layer address */
> +static unsigned long damon_pa_core_addr(phys_addr_t pa,
> +		unsigned long addr_unit)
> +{
> +#ifdef __i386__

Can we use the following condition instead?

#if !defined(CONFIG_64BIT) && defined(CONFIG_PHYS_ADDR_T_64BIT)

Thanks,
Quanmin Yan

> +	do_div(pa, addr_unit);
> +	return pa;
> +#else
> +	return pa / addr_unit;
> +#endif
> +}
> +
>   static unsigned long damon_pa_pageout(struct damon_region *r,
>   		unsigned long addr_unit, struct damos *s,
>   		unsigned long *sz_filter_passed)
> @@ -190,7 +202,7 @@ static unsigned long damon_pa_pageout(struct damon_region *r,
>   	applied = reclaim_pages(&folio_list);
>   	cond_resched();
>   	s->last_applied = folio;
> -	return applied * PAGE_SIZE / addr_unit;
> +	return damon_pa_core_addr(applied * PAGE_SIZE, addr_unit);
>   }
>   
>   static inline unsigned long damon_pa_mark_accessed_or_deactivate(