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

[SeongJae Park <sj@kernel.org>]

On Tue, 26 Aug 2025 11:16:56 +0800 Quanmin Yan <yanquanmin1@huawei.com> wrote:

> 
> 在 2025/8/25 23:12, SeongJae Park 写道:
> > On Fri, 22 Aug 2025 17:34:11 +0800 Quanmin Yan <yanquanmin1@huawei.com> wrote:
[...]
> > ==== 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@kernel.org>
> > To: Andrew Morton <akpm@linux-foundation.org>
> > Cc: SeongJae Park <sj@kernel.org>
> > Cc: damon@lists.linux.dev
> > Cc: kernel-team@meta.com
> > Cc: linux-kernel@vger.kernel.org
> > Cc: linux-mm@kvack.org
> > 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@intel.com>
> > Closes: https://lore.kernel.org/oe-kbuild-all/202508241831.EKwdwXZL-lkp@intel.com/
> > Signed-off-by: SeongJae Park <sj@kernel.org>
> > ---
> >   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)

To my understanding, this issue happens only on i386, not every 32bit
architectures.  So I think i386 specific condition is better.


Thanks,
SJ

[...]