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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: <20260220090409.1784bc64@pumpkin> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260220090409.1784bc64@pumpkin> On Fri, Feb 20, 2026 at 09:04:09AM +0000, David Laight wrote: > On Thu, 19 Feb 2026 15:08:51 +0000 > Kiryl Shutsemau wrote: > > > No, there's no new hardware (that I know of). I want to explore what page size > > means. > > > > The kernel uses the same value - PAGE_SIZE - for two things: > > > > - the order-0 buddy allocation size; > > > > - the granularity of virtual address space mapping; > > Also the 'random' buffers that are PAGE_SIZE rather than 4k. Yeah, in some places we use PAGE_SIZE just because without any reason. > I also wonder how is affects mmap of kernel memory and the alignement > of PCIe windows (etc). Kernel, as userspace, is free to map memory PTE_SIZE granularity. -- Kiryl Shutsemau / Kirill A. Shutemov