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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: <915aafb3-d1ff-4ae9-8751-f78e333a1f5f@kernel.org> <17c5708d-3859-49a5-814e-bc3564bc3ac6@kernel.org> <32ed82dd-62c3-4a5c-8bae-9465afd7e75f@kernel.org> <06684dc4-3902-4452-824a-ee2064314d24@kernel.org> 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=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <06684dc4-3902-4452-824a-ee2064314d24@kernel.org> On Mon, Feb 23, 2026 at 12:27:33PM +0100, David Hildenbrand (Arm) wrote: > On 2/23/26 12:13, Kiryl Shutsemau wrote: > > On Mon, Feb 23, 2026 at 12:04:10PM +0100, David Hildenbrand (Arm) wrote: > > > On 2/20/26 20:33, Kalesh Singh wrote: > > > > On Fri, Feb 20, 2026 at 8:30 AM David Hildenbrand (Arm) > > > > wrote: > > > > > > > > I think most issues will stem from linkers setting the default ELF > > > > segment alignment (max-page-size) for x86 to 4096. So those ELFs will > > > > not load correctly or at all on the larger emulated granularity. > > > > > > Right, I assume that they will have to be thought about that, and possibly, > > > some binaries/libraries recompiled. > > > > I think backward compatibility is important and I believe we can get > > there without ABI break. And optimize from there. > > > > BTW, x86-64 SysV ABI allows for 64k page size: > > > > Systems are permitted to use any power-of-two page size between > > 4KB and 64KB, inclusive. > > > > But it doesn't work in practice. > > Even in well controlled environments you would run in a hyperscaler? I have not invested much time into investigating this. I intentionally targeted compatible version assuming it will be better received by upstream. I want it to be usable outside specially cured userspace. 64k might not be good fit for a desktop, but 16k can be a different story. -- Kiryl Shutsemau / Kirill A. Shutemov