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Fri, 6 Feb 2026 09:43:15 -0500 (EST) Date: Fri, 6 Feb 2026 14:43:10 +0000 From: Kiryl Shutsemau To: Gladyshev Ilya Cc: gorbunov.ivan@h-partners.com, artem.kuzin@huawei.com, stepanov.anatoly@huawei.com, alexander.grubnikov@huawei.com, David Hildenbrand , Andrew Morton , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Zi Yan , Harry Yoo , "Matthew Wilcox (Oracle)" , Yu Zhao , Baolin Wang , Will Deacon , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm: make ref_unless functions unless_zero only Message-ID: References: <20260206133328.426921-1-gladyshev.ilya1@h-partners.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260206133328.426921-1-gladyshev.ilya1@h-partners.com> X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 4B3CB40006 X-Stat-Signature: 1671y67jmhwkbrmjs1ud4w7wb5um4hyg X-Rspam-User: X-HE-Tag: 1770389001-678659 X-HE-Meta: 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 3YQz89XL 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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 > Signed-off-by: Gorbunov Ivan > Signed-off-by: Gladyshev Ilya > Acked-by: David Hildenbrand (Arm) Acked-by: Kiryl Shutsemau -- Kiryl Shutsemau / Kirill A. Shutemov