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Wed, 25 Mar 2026 01:46:51 -0700 (PDT) From: Askar Safin To: jack@suse.cz Cc: Liam.Howlett@oracle.com, akpm@linux-foundation.org, ardb@kernel.org, baolin.wang@linux.alibaba.com, catalin.marinas@arm.com, david@kernel.org, dev.jain@arm.com, hughd@google.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, lorenzo.stoakes@oracle.com, lsf-pc@lists.linux-foundation.org, mhocko@suse.com, rppt@kernel.org, ryan.roberts@arm.com, surenb@google.com, vbabka@suse.cz, will@kernel.org, willy@infradead.org Subject: Re: [Lsf-pc] [LSF/MM/BPF TOPIC] Per-process page size Date: Wed, 25 Mar 2026 11:46:32 +0300 Message-ID: <20260325084633.906324-1-safinaskar@gmail.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Jan Kara : > > Is there some other way for someone to block a page from getting evicted > > from the pagecache? > > > > We have this memfd_pin_folios() thing, but I don't think we have something > > comparable for ordinary pagecache files. > > > > ... putting them into a pipe and never reading from the pipe maybe (I assume > > that's what splice() does, but not sure if it actually places the pages in > > there or whether it creates a copy first)? > > Standard splice copies data first (it's using standard IO callbacks such as > ->read_iter) so that doesn't pin page cache AFAICT. Only vmsplice(2) does > but that requires mmap. Splice from page cache to pipe sometimes doesn't copy data. That is why test program mentioned here may print "new": https://lore.kernel.org/all/CAHk-=wjixHw6n_R5TQWW1r0a+GgFAPGw21KMj6obkzr3qXXbYA@mail.gmail.com/ -- Askar Safin