From: Kiryl Shutsemau <kirill@shutemov.name>
To: Gladyshev Ilya <gladyshev.ilya1@h-partners.com>
Cc: gorbunov.ivan@h-partners.com, artem.kuzin@huawei.com,
stepanov.anatoly@huawei.com, alexander.grubnikov@huawei.com,
David Hildenbrand <david@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Lorenzo Stoakes <lorenzo.stoakes@oracle.com>,
"Liam R. Howlett" <Liam.Howlett@oracle.com>,
Vlastimil Babka <vbabka@suse.cz>,
Mike Rapoport <rppt@kernel.org>,
Suren Baghdasaryan <surenb@google.com>,
Michal Hocko <mhocko@suse.com>, Zi Yan <ziy@nvidia.com>,
Harry Yoo <harry.yoo@oracle.com>,
"Matthew Wilcox (Oracle)" <willy@infradead.org>,
Yu Zhao <yuzhao@google.com>,
Baolin Wang <baolin.wang@linux.alibaba.com>,
Will Deacon <will@kernel.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: make ref_unless functions unless_zero only
Date: Fri, 6 Feb 2026 14:43:10 +0000 [thread overview]
Message-ID: <aYX96BcEn0EPiUlH@thinkstation> (raw)
In-Reply-To: <20260206133328.426921-1-gladyshev.ilya1@h-partners.com>
On Fri, Feb 06, 2026 at 01:33:02PM +0000, 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>
> Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Acked-by: Kiryl Shutsemau <kas@kernel.org>
--
Kiryl Shutsemau / Kirill A. Shutemov
next prev parent reply other threads:[~2026-02-06 14:43 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-06 13:33 [PATCH] mm: make ref_unless functions unless_zero only Gladyshev Ilya
2026-02-06 14:43 ` Kiryl Shutsemau [this message]
2026-02-06 15:46 ` Zi Yan
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