From: "David Hildenbrand (Arm)" <david@kernel.org>
To: Tal Zussman <tz2294@columbia.edu>,
Andrew Morton <akpm@linux-foundation.org>,
Chris Li <chrisl@kernel.org>, Kairui Song <kasong@tencent.com>,
Kemeng Shi <shikemeng@huaweicloud.com>,
Nhat Pham <nphamcs@gmail.com>, Baoquan He <baoquan.he@linux.dev>,
Barry Song <baohua@kernel.org>,
Youngjun Park <youngjun.park@lge.com>, Zi Yan <ziy@nvidia.com>,
Baolin Wang <baolin.wang@linux.alibaba.com>,
"Liam R. Howlett" <liam@infradead.org>,
Nico Pache <nico.pache@linux.dev>,
Ryan Roberts <ryan.roberts@arm.com>, Dev Jain <dev.jain@arm.com>,
Lance Yang <lance.yang@linux.dev>,
Usama Arif <usama.arif@linux.dev>,
Kiryl Shutsemau <kas@kernel.org>,
Lorenzo Stoakes <ljs@kernel.org>, Rik van Riel <riel@surriel.com>,
Vlastimil Babka <vbabka@kernel.org>, Harry Yoo <harry@kernel.org>,
Jann Horn <jannh@google.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Yosry Ahmed <yosry@kernel.org>,
Chengming Zhou <chengming.zhou@linux.dev>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Mark Rutland <mark.rutland@arm.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 2/8] mm/huge_memory: add a comment to the open-coded swap entry
Date: Wed, 9 Sep 2026 15:52:14 +0200 [thread overview]
Message-ID: <6067ba05-82e6-434c-b717-93ea2fb7d853@kernel.org> (raw)
In-Reply-To: <20260908-folio_swap_entry-v2-2-ee6d01dfa5e1@columbia.edu>
On 9/8/26 17:16, Tal Zussman wrote:
> The swap entry of each new folio in __split_folio_to_order() is
> computed by hand from folio->swap rather than with folio_swap_entry(),
> because the folio's page count is not valid while it is being split.
> Add a comment explaining this.
>
> Signed-off-by: Tal Zussman <tz2294@columbia.edu>
> ---
> mm/huge_memory.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> index d1ce061601bc..1fabdcbd8c8f 100644
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -3763,6 +3763,10 @@ static void __split_folio_to_order(struct folio *folio, int old_order,
> */
> VM_WARN_ON_ONCE_PAGE(new_folio->private, new_head);
>
> + /*
> + * Not all folio fields are valid during a split, so open-code
> + * the swap entry rather than using folio_swap_entry().
> + */
> if (folio_test_swapcache(folio))
> new_folio->swap.val = folio->swap.val + i;
>
>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
--
Cheers,
David
next prev parent reply other threads:[~2026-09-09 13:52 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-08 15:16 [PATCH v2 0/8] mm: remove page_swap_entry() Tal Zussman
2026-09-08 15:16 ` [PATCH v2 1/8] mm/swap: add folio_swap_entry() and folio_page_swap_entry() Tal Zussman
2026-09-09 14:00 ` David Hildenbrand (Arm)
2026-09-09 17:21 ` Tal Zussman
2026-09-09 17:25 ` David Hildenbrand (Arm)
2026-09-08 15:16 ` [PATCH v2 2/8] mm/huge_memory: add a comment to the open-coded swap entry Tal Zussman
2026-09-08 15:26 ` Zi Yan
2026-09-09 13:52 ` David Hildenbrand (Arm) [this message]
2026-09-08 15:16 ` [PATCH v2 3/8] mm/rmap: use folio_page_swap_entry() in ttu_anon_swapbacked_folio() Tal Zussman
2026-09-09 14:00 ` David Hildenbrand (Arm)
2026-09-08 15:16 ` [PATCH v2 4/8] mm/zswap: use folio_swap_entry() in zswap_store_page() Tal Zussman
2026-09-09 14:00 ` David Hildenbrand (Arm)
2026-09-08 15:16 ` [PATCH v2 5/8] mm/swapfile: use folio_page_swap_entry() Tal Zussman
2026-09-09 14:01 ` David Hildenbrand (Arm)
2026-09-08 15:16 ` [PATCH v2 6/8] arm64: mte: make mte_save_tags() and mte_restore_tags() static Tal Zussman
2026-09-09 14:01 ` David Hildenbrand (Arm)
2026-09-08 15:16 ` [PATCH v2 7/8] arm64: mte: pass the swap entry to mte_save_tags() Tal Zussman
2026-09-09 14:06 ` David Hildenbrand (Arm)
2026-09-08 15:16 ` [PATCH v2 8/8] mm/swap: remove page_swap_entry() Tal Zussman
2026-09-09 14:06 ` David Hildenbrand (Arm)
2026-09-08 17:55 ` [PATCH v2 0/8] mm: " Andrew Morton
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