* [PATCH v3] mm/damon/paddr: fix missing folio_put()
@ 2023-02-22 6:42 Andrew Yang
2023-02-22 18:26 ` SeongJae Park
0 siblings, 1 reply; 2+ messages in thread
From: Andrew Yang @ 2023-02-22 6:42 UTC (permalink / raw)
To: SeongJae Park, Andrew Morton, Matthias Brugger,
AngeloGioacchino Del Regno
Cc: wsd_upstream, casper.li, andrew.yang, stable, damon, linux-mm,
linux-kernel, linux-arm-kernel, linux-mediatek
From: "andrew.yang" <andrew.yang@mediatek.com>
damon_get_folio() would always increase folio _refcount and
folio_isolate_lru() would increase folio _refcount if the folio's lru
flag is set.
If an unevictable folio isolated successfully, there will be two more
_refcount. The one from folio_isolate_lru() will be decreased in
folio_puback_lru(), but the other one from damon_get_folio() will be
left behind. This causes a pin page.
Whatever the case, the _refcount from damon_get_folio() should be
decreased.
Signed-off-by: andrew.yang <andrew.yang@mediatek.com>
Fixes: 57223ac29584 ("mm/damon/paddr: support the pageout scheme")
Cc: <stable@vger.kernel.org> # 5.16.x
---
v3:
add fixes tag and cc stable
v2:
according to David's suggestion
1. revise subject
according to SeongJae's suggestions
1. rebase to mm-unstable tree
2. remove braces for th single statements
---
mm/damon/paddr.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c
index 607bb69e526c..6c655d9b5639 100644
--- a/mm/damon/paddr.c
+++ b/mm/damon/paddr.c
@@ -250,12 +250,11 @@ static unsigned long damon_pa_pageout(struct damon_region *r, struct damos *s)
folio_put(folio);
continue;
}
- if (folio_test_unevictable(folio)) {
+ if (folio_test_unevictable(folio))
folio_putback_lru(folio);
- } else {
+ else
list_add(&folio->lru, &folio_list);
- folio_put(folio);
- }
+ folio_put(folio);
}
applied = reclaim_pages(&folio_list);
cond_resched();
--
2.18.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v3] mm/damon/paddr: fix missing folio_put()
2023-02-22 6:42 [PATCH v3] mm/damon/paddr: fix missing folio_put() Andrew Yang
@ 2023-02-22 18:26 ` SeongJae Park
0 siblings, 0 replies; 2+ messages in thread
From: SeongJae Park @ 2023-02-22 18:26 UTC (permalink / raw)
Cc: SeongJae Park, Andrew Morton, Matthias Brugger,
AngeloGioacchino Del Regno, wsd_upstream, casper.li,
andrew . yang, stable, damon, linux-mm, linux-kernel,
linux-arm-kernel, linux-mediatek
Hi Andrew,
Thank you for revising this patch!
> From: "andrew.yang" <andrew.yang@mediatek.com>
>
> damon_get_folio() would always increase folio _refcount and
> folio_isolate_lru() would increase folio _refcount if the folio's lru
> flag is set.
>
> If an unevictable folio isolated successfully, there will be two more
> _refcount. The one from folio_isolate_lru() will be decreased in
> folio_puback_lru(), but the other one from damon_get_folio() will be
> left behind. This causes a pin page.
>
> Whatever the case, the _refcount from damon_get_folio() should be
> decreased.
>
> Signed-off-by: andrew.yang <andrew.yang@mediatek.com>
> Fixes: 57223ac29584 ("mm/damon/paddr: support the pageout scheme")
> Cc: <stable@vger.kernel.org> # 5.16.x
Reviewed-by: SeongJae Park <sj@kernel.org>
This may not cleanly applicable on 6.1.y and 6.2.y. I would post backports
once this is merged in the mainline, unless others do earlier than me.
Thanks,
SJ
> ---
> v3:
> add fixes tag and cc stable
> v2:
> according to David's suggestion
> 1. revise subject
> according to SeongJae's suggestions
> 1. rebase to mm-unstable tree
> 2. remove braces for th single statements
> ---
> mm/damon/paddr.c | 7 +++----
> 1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c
> index 607bb69e526c..6c655d9b5639 100644
> --- a/mm/damon/paddr.c
> +++ b/mm/damon/paddr.c
> @@ -250,12 +250,11 @@ static unsigned long damon_pa_pageout(struct damon_region *r, struct damos *s)
> folio_put(folio);
> continue;
> }
> - if (folio_test_unevictable(folio)) {
> + if (folio_test_unevictable(folio))
> folio_putback_lru(folio);
> - } else {
> + else
> list_add(&folio->lru, &folio_list);
> - folio_put(folio);
> - }
> + folio_put(folio);
> }
> applied = reclaim_pages(&folio_list);
> cond_resched();
> --
> 2.18.0
>
>
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