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Thu, 19 Feb 2026 17:05:38 -0500 (EST) Date: Thu, 19 Feb 2026 22:05:37 +0000 From: Kiryl Shutsemau To: Dave Hansen Cc: lsf-pc@lists.linux-foundation.org, linux-mm@kvack.org, x86@kernel.org, linux-kernel@vger.kernel.org, Andrew Morton , David Hildenbrand , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , Lorenzo Stoakes , "Liam R. Howlett" , Mike Rapoport , Matthew Wilcox , Johannes Weiner , Usama Arif Subject: Re: [LSF/MM/BPF TOPIC] 64k (or 16k) base page size on x86 Message-ID: References: <46817fe5-7166-4734-bad3-3109cc7feb1e@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <46817fe5-7166-4734-bad3-3109cc7feb1e@intel.com> X-Rspam-User: X-Stat-Signature: o1u7cc9pdufw37x6td4dcbzm3ke5qsma X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 105F6A000D X-HE-Tag: 1771538746-534320 X-HE-Meta: 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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 Thu, Feb 19, 2026 at 09:08:57AM -0800, Dave Hansen wrote: > On 2/19/26 07:08, Kiryl Shutsemau wrote: > > - The order-0 page size cuts struct page overhead by a factor of 16. From > > ~1.6% of RAM to ~0.1%; > ... > But, it will mostly be getting better performance at the _cost_ of > consuming more RAM, not saving RAM. That's fair. The problem with struct page memory consumption is that it is static and cannot be reclaimed. You pay the struct page tax no matter what. Page cache rounding overhead can be large, but a motivated userspace can keep it under control by avoiding splitting a dataset into many small files. And this memory is reclaimable. -- Kiryl Shutsemau / Kirill A. Shutemov