From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 162B5341AB8 for ; Thu, 19 Feb 2026 15:21:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.92.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771514463; cv=none; b=jH5vFVzuzZrmreCaRMYCNYa1wITa5tSHZpCsw2h3IB7bEZ0KDQoRyngL60UgnDbiB+gYt8ehEeieI6TNBm9fBSFdMcj4Huc8B3MYfs77LqlDFLcy8edEbUYnUrm98OYMKDcSrA44h5QV5kydyHhb9PU/4ZrTwzNjrZqpyoCNg8s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771514463; c=relaxed/simple; bh=YSDBsV9i9LuKlnV7iku+C/cAt8k904DSKeVDDgfDG7w=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=IrNw2xSvJr5J2tAItRI+enq8zFOTKEiMzwMdfuvB6ygHkBHK2SKv09j7dXEOsJDu/qxdoK5YTlXOeXXKe5QKUIO+H8hb5ynurqcwcWBcUeZOGz3GSi+VUbmhycs19Mqwh8FNSHbVAKmsBuL+NpaJVLxstuJE7f7pkaVFxgcLy+c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=f+zedE0z; arc=none smtp.client-ip=90.155.92.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="f+zedE0z" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=GJWQHabnh6u189YCJEq42YLB+uPwZUwkYJ7q/vk+sIY=; b=f+zedE0zzjUGv9Mglc5T/eVrMT 7JM6mK0oAgYogGk3XbEpjFlHTEtueSGdnuIv79gW/a+c0XyfzDZjQjWb8JvcvtGRuAzW59Di6RGNG 2evcxWw0L196DIh+jk3COnP7ev4Xaw14jXdjdIcR8CnDiSgY876fTHVEVHg1Buz13/hxSNLOGAoXr NzDl59gsBj6D4fiKzz8A7jbHL5wYPMX0K2iW5fAzDYmr3YooahPaD/oFPfjXZw1AVgVLanv3ZkFYp mRH0GdRHsdzIF0GHOWGVlk6g4+FO31HMwxBzvxGPPyO738RcAH2bajKX7qq4lv5p3zt+G3kp90IPP CvXz6LUg==; Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1vt5pd-00000001RvQ-3eH1; Thu, 19 Feb 2026 15:20:47 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 10EB930075B; Thu, 19 Feb 2026 16:20:45 +0100 (CET) Date: Thu, 19 Feb 2026 16:20:45 +0100 From: Peter Zijlstra To: Kiryl Shutsemau 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: <20260219152045.GR1395416@noisy.programming.kicks-ass.net> References: <20260219151729.GK1282955@noisy.programming.kicks-ass.net> 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: <20260219151729.GK1282955@noisy.programming.kicks-ass.net> On Thu, Feb 19, 2026 at 04:17:29PM +0100, Peter Zijlstra wrote: > On Thu, Feb 19, 2026 at 03:08:51PM +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; > > > > I think we can benefit from separating these two meanings and allowing > > order-0 allocations to be larger than the virtual address space covered by a > > PTE entry. > > Didn't AA do this a decade ago or somesuch? https://lwn.net/Articles/240914/