On Tue, 2023-02-21 at 18:35 +0000, SeongJae Park wrote:
> Hi Andrew,
>
>
> On Tue, 21 Feb 2023 17:03:13 +0800 Andrew Yang <
> andrew.yang@xxxxxxxxxxxx> wrote:
>
> > From: "andrew.yang" <andrew.yang@xxxxxxxxxxxx>
> >
> > damon_get_page() would always increase page _refcount and
> > isolate_lru_page() would increase page _refcount if the page's lru
> > flag is set.
> >
> > If a unevictable page isolated successfully, there will be two more
> > _refcount. The one from isolate_lru_page() will be decreased in
> > putback_lru_page(), but the other one from damon_get_page() will be
> > left behind. This causes a pin page.
> >
> > Whatever the case, the _refcount from damon_get_page() should be
> > decreased.
>
> Thank you for finding this issue! I think the David suggested
> subject[1] is
> better, though.
>
> I think we could add below Fixes: and Cc: tags?
>
> Fixes: 57223ac29584 ("mm/damon/paddr: support the pageout scheme")
> Cc: <stable@xxxxxxxxxxxxxxx> # 5.16.x
>
> >
> > Signed-off-by: andrew.yang <andrew.yang@xxxxxxxxxxxx>
> > ---
> > 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 e1a4315c4be6..56d8abd08fb1 100644
> > --- a/mm/damon/paddr.c
> > +++ b/mm/damon/paddr.c
> > @@ -223,8 +223,8 @@ static unsigned long damon_pa_pageout(struct
> > damon_region *r)
> > putback_lru_page(page);
> > } else {
> > list_add(&page->lru, &page_list);
> > - put_page(page);
> > }
> > + put_page(page);
>
> Seems your patch is not based on mm-unstable tree[2]. Could you
> please rebase
> on it?
>
> Also, let's remove the braces for the single statements[3].
>
> [1]
> https://lore.kernel.org/damon/1b3e8e88-ed5c-7302-553f-4ddb3400d466@xxxxxxxxxx/
> [2]
> https://urldefense.com/v3/__https://docs.kernel.org/next/mm/damon/maintainer-profile.html*scm-trees__;Iw!!CTRNKA9wMg0ARbw!jlYra3CQPXNsppOWspkAkRO2AfKJEoMyAu8_JvZ9eY5b0YQbTB6sX1Gas-ZRtrMKXfxxpi7PEe8yeg$ ;
>
> [3]
> https://urldefense.com/v3/__https://docs.kernel.org/process/coding-style.html?highlight=coding*style*placing-braces-and-spaces__;KyM!!CTRNKA9wMg0ARbw!jlYra3CQPXNsppOWspkAkRO2AfKJEoMyAu8_JvZ9eY5b0YQbTB6sX1Gas-ZRtrMKXfxxpi69jIOtSQ$ ;
>
>
>
> Thanks,
> SJ
>
> > }
> > applied = reclaim_pages(&page_list);
> > cond_resched();
> > --
> > 2.18.0
Thanks for both of your suggestions, I will update the patch.
