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From: Shakeel Butt To: "Barry Song (Xiaomi)" Cc: akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, david@kernel.org, ljs@kernel.org, liam@infradead.org, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, chrisl@kernel.org, kasong@tencent.com, shikemeng@huaweicloud.com, nphamcs@gmail.com, baoquan.he@linux.dev, youngjun.park@lge.com, jp.kobryn@linux.dev, usama.arif@linux.dev Subject: Re: [RFC PATCH 2/3] mm: drop stale folio_ref_count()==1 check in do_swap_page reuse logic Message-ID: References: <20260611105124.98668-1-baohua@kernel.org> <20260611105124.98668-3-baohua@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260611105124.98668-3-baohua@kernel.org> X-Migadu-Flow: FLOW_OUT X-Rspamd-Queue-Id: 8A51C120005 X-Stat-Signature: hsh7ugznadttnzbi84fxymrjurwz3hwh X-Rspamd-Server: rspam03 X-Rspam-User: X-HE-Tag: 1781201632-863902 X-HE-Meta: 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 inCHJVYQ Ou/5b4k/FSoc7IbGZARYYm3913kEGFasYiVsjC5zC1WtRvEb0IFcbh9l8REbyY6oDYK97Pqmz9kVKyf4j955T82zG8O7ePFOaFK5urYJ6ivMdP/EHJELOzU9cgmOH1JEHhW+v2Nbc3EheKQzPXolnNg3u6W5zls+n0LuhJtzVbSIcaaldyJWjW4p6HxdRGrQ1Mr+QO/ym/aiE9/8eMPum0IrTjWUY2R9Y/mRtQRgrWqXK5/m3Qm/URj3b6+D9a9sf+9ONprQTKLHsbGaDdFJd0NpQxDUzTqS746rAon41EMyYAgI= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Jun 11, 2026 at 06:51:23PM +0800, Barry Song (Xiaomi) wrote: > The "we just allocated them without exposing them to the swapcache" > case no longer exists, as Kairui has routed synchronous I/O through > the swapcache as well in his series "unify swapin use swap cache and > cleanup flags"[1]. As a result, folio_ref_count() should never be 1 > in this path, since at least two references are held (base ref plus > swapcache). Remove the folio_ref_count()==1 check and update the > comment accordingly. > > [1] https://lore.kernel.org/all/20251220-swap-table-p2-v5-0-8862a265a033@tencent.com/ > Signed-off-by: Barry Song (Xiaomi) Acked-by: Shakeel Butt