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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


  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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