From: "David Hildenbrand (Arm)" <david@kernel.org>
To: Gladyshev Ilya <gladyshev.ilya1@h-partners.com>, patchwork@huawei.com
Cc: guohanjun@huawei.com, wangkefeng.wang@huawei.com,
weiyongjun1@huawei.com, yusongping@huawei.com,
leijitang@huawei.com, artem.kuzin@huawei.com,
stepanov.anatoly@huawei.com, alexander.grubnikov@huawei.com,
gorbunov.ivan@h-partners.com, akpm@linux-foundation.org,
lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com,
vbabka@suse.cz, rppt@kernel.org, surenb@google.com,
mhocko@suse.com, ziy@nvidia.com, harry.yoo@oracle.com,
willy@infradead.org, yuzhao@google.com,
baolin.wang@linux.alibaba.com, muchun.song@linux.dev,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH 1/2] mm: make ref_unless functions unless_zero only
Date: Fri, 6 Feb 2026 14:16:58 +0100 [thread overview]
Message-ID: <2c984546-3e26-40e0-b9d8-68383555ced2@kernel.org> (raw)
In-Reply-To: <d30cf64b3b48080d21a5d14b79d51a82e0f80e7e.1766145604.git.gladyshev.ilya1@h-partners.com>
On 12/19/25 13:46, Gladyshev Ilya wrote:
> There are no users of (folio/page)_ref_add_unless(page, nr, u) with
> u != 0 [1] and all current users are "internal" for page refcounting API.
> This allows us to safely drop this parameter and reduce function
> semantics to the "unless zero" cases only, which will be optimized in
> the following patch.
>
> If needed, these functions for the u!=0 cases can be trivially
> reintroduced later using the same atomic_add_unless operations as before.
>
> [1]: The last user was dropped in v5.18 kernel, commit 27674ef6c73f
> ("mm: remove the extra ZONE_DEVICE struct page refcount"). There is no
> trace of discussion as to why this cleanup wasn't done earlier.
>
> Co-developed-by: Gorbunov Ivan <gorbunov.ivan@h-partners.com>
> Signed-off-by: Gorbunov Ivan <gorbunov.ivan@h-partners.com>
> Signed-off-by: Gladyshev Ilya <gladyshev.ilya1@h-partners.com>
> ---
This one makes a lot of sense even without #2. Can you send that out
early as a standalone patch?
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
--
Cheers,
David
next prev parent reply other threads:[~2026-02-06 13:17 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-19 12:46 [RFC PATCH 0/2] mm: improve folio refcount scalability Gladyshev Ilya
2025-12-19 12:46 ` [RFC PATCH 1/2] mm: make ref_unless functions unless_zero only Gladyshev Ilya
2026-02-06 13:16 ` David Hildenbrand (Arm) [this message]
2025-12-19 12:46 ` [RFC PATCH 2/2] mm: implement page refcount locking via dedicated bit Gladyshev Ilya
2025-12-19 14:50 ` Kiryl Shutsemau
2025-12-19 16:18 ` Gladyshev Ilya
2025-12-19 17:46 ` Kiryl Shutsemau
2025-12-19 19:08 ` Gladyshev Ilya
2025-12-22 13:33 ` Kiryl Shutsemau
2025-12-19 18:17 ` Gregory Price
2025-12-22 12:42 ` Gladyshev Ilya
2026-01-12 8:30 ` [RFC PATCH 0/2] mm: improve folio refcount scalability Gladyshev Ilya
2026-01-12 11:49 ` Kiryl Shutsemau
2026-01-12 14:32 ` Gladyshev Ilya
2026-01-12 16:17 ` Kiryl Shutsemau
2026-01-13 7:31 ` Gladyshev Ilya
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