linux-kernel - Re: [PATCH RFC 18/29] mm: remove __folio_test

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Message-ID: <d2a304a0-767f-41b9-b040-a43ce58bdff7@redhat.com>
Date: Mon, 30 Jun 2025 12:38:39 +0200
From: David Hildenbrand <david@...hat.com>
To: linux-kernel@...r.kernel.org
Cc: linux-mm@...ck.org, linux-doc@...r.kernel.org,
 linuxppc-dev@...ts.ozlabs.org, virtualization@...ts.linux.dev,
 linux-fsdevel@...r.kernel.org, Andrew Morton <akpm@...ux-foundation.org>,
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 Shakeel Butt <shakeel.butt@...ux.dev>
Subject: Re: [PATCH RFC 18/29] mm: remove __folio_test_movable()

> @@ -1164,7 +1148,6 @@ static int migrate_folio_unmap(new_folio_t get_new_folio,
>   	int rc = -EAGAIN;
>   	int old_page_state = 0;
>   	struct anon_vma *anon_vma = NULL;
> -	bool is_lru = data_race(!__folio_test_movable(src));
>   	bool locked = false;
>   	bool dst_locked = false;
>   
> @@ -1265,7 +1248,7 @@ static int migrate_folio_unmap(new_folio_t get_new_folio,
>   		goto out;
>   	dst_locked = true;
>   
> -	if (unlikely(!is_lru)) {
> +	if (unlikely(page_has_movable_ops(&dst->page))) {

While doing more testing, I found a weird bug where we end up having 
balloon pages isolated forever, and never putback/migrated. So neither 
the balloon can deflate them nor the migration migrate them.

This line here must be

if (unlikely(page_has_movable_ops(&src->page))) {

But I am not sure yet if that's the issue I am chasing :)

-- 
Cheers,

David / dhildenb