linux-kernel - Re: [PATCH v2 05/11] mm/damon/paddr: support addr_unit for MIGRATE

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Message-Id: <20250825151513.36488-1-sj@kernel.org>
Date: Mon, 25 Aug 2025 08:15:13 -0700
From: SeongJae Park <sj@...nel.org>
To: Quanmin Yan <yanquanmin1@...wei.com>
Cc: SeongJae Park <sj@...nel.org>,
	akpm@...ux-foundation.org,
	damon@...ts.linux.dev,
	linux-kernel@...r.kernel.org,
	linux-mm@...ck.org,
	wangkefeng.wang@...wei.com,
	zuoze1@...wei.com,
	kernel-team@...a.com
Subject: Re: [PATCH v2 05/11] mm/damon/paddr: support addr_unit for MIGRATE_{HOT,COLD}

On Fri, 22 Aug 2025 17:34:13 +0800 Quanmin Yan <yanquanmin1@...wei.com> wrote:

> From: SeongJae Park <sj@...nel.org>
> 
> Add support of addr_unit for DAMOS_MIGRATE_HOT and DAMOS_MIGRATE_COLD
> action handling from the DAMOS operation implementation for the physical
> address space.
[...]
> -	return applied * PAGE_SIZE;
> +	return applied * PAGE_SIZE / addr_unit;
>  }

This can cause __udivdi3 linking issue similar to a report [1] from kernel test
robot.  Andrew, could you please add below attaching fixup?

[1] https://lore.kernel.org/oe-kbuild-all/202508241831.EKwdwXZL-lkp@intel.com/


Thanks,
SJ

[...]

==== Attachment 0 (0003-mm-damon-paddr-use-do_div-on-i386-for-damon_pa_migra.patch) ====
>From hackermail Thu Jan  1 00:00:00 1970
From: SeongJae Park <sj@...nel.org>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: SeongJae Park <sj@...nel.org>
Cc: damon@...ts.linux.dev
Cc: kernel-team@...a.com
Cc: linux-kernel@...r.kernel.org
Cc: linux-mm@...ck.org
Date: Mon, 25 Aug 2025 07:46:24 -0700
Subject: [PATCH 3/3] mm/damon/paddr: use do_div() on i386 for damon_pa_migrate()
         return value

Otherwise, __udivdi3 linking issue happens on certain configs.

Signed-off-by: SeongJae Park <sj@...nel.org>
---
 mm/damon/paddr.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c
index 6fb92ecc513d..34248b742a73 100644
--- a/mm/damon/paddr.c
+++ b/mm/damon/paddr.c
@@ -286,7 +286,7 @@ static unsigned long damon_pa_migrate(struct damon_region *r,
 	applied = damon_migrate_pages(&folio_list, s->target_nid);
 	cond_resched();
 	s->last_applied = folio;
-	return applied * PAGE_SIZE / addr_unit;
+	return damon_pa_core_addr(applied * PAGE_SIZE, addr_unit);
 }
 
 static unsigned long damon_pa_stat(struct damon_region *r,
-- 
2.39.5