From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (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 D442833A6FB for ; Thu, 19 Feb 2026 17:47:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771523248; cv=none; b=oD/bOyqzJQKX/mhpR6Bao7PpVGDSlV3tOCemvE+5M45P4Q70MbclCbPCzhhTs2llg79YaYStJEwu9HveMvoswUFdtIj1JHROdlEjl9tUQ9U4QmIusAY8v65fTZsBeasG4Pac6n4qVKpRkcAqFHyXCvbybMrsYCo84b4e3DYsohI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771523248; c=relaxed/simple; bh=QNSQih2B2HrGm+tuo1GwbpIZsl4BOQ3a97D06J+PICc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=GbDwd1U5tzDfwqfgtjkio8YUeLzn6fCslTQ2tM5QuWBuFhAGn4ilturepS83q0uKtoHwkF1DM15VaH/LkSQQAkdS1MDXNSQ/Oip6h9eNZrxSwjBp6HKUh1kQi1vhhT8c/h0ePRWwWACV0MISkYmW99I2bkya2Gtwj1zF9EaCZK4= 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=p7Pg2dMS; arc=none smtp.client-ip=90.155.50.34 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="p7Pg2dMS" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; 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=LEXDb1RTP1nApbTBOd0H0UpylDzp2isc3oWrquK2Hs8=; b=p7Pg2dMSmxSq9UV5uLTY8iH5YQ 1/Hci6RWc6b2uZbQkYi+o6O1S6ETwtncBsuN5xW65xjA5fbBMZTTLvcuBsXmNvCPpeS1mkfw3VRno EpvlXPnYXxH7zL+VWk+lJYjdbwlnoVvHiMBn8gyxoVG/jbud0njpPbKybaYVP+eO5GQftxsFaIogt v1y/TK8ja+S0IWGWny7hJpcoOOLeDgVrc3fOBdOTVJg/knTviHLeXTCNrjMkRko/rmbs7Lnormjet CedBMFn5sVhDZdZ79nUWy3yCnRDB+4w+l8EzxHkfZ+LHeFwOA+ljw1k+6mkssWe7WCW8S/CeCyxqy zuyioeFA==; Received: from willy by casper.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1vt87W-00000007z8A-1MsV; Thu, 19 Feb 2026 17:47:22 +0000 Date: Thu, 19 Feb 2026 17:47:22 +0000 From: Matthew Wilcox 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 , Johannes Weiner , Usama Arif Subject: Re: [LSF/MM/BPF TOPIC] 64k (or 16k) base page size on x86 Message-ID: References: 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: On Thu, Feb 19, 2026 at 03:08:51PM +0000, Kiryl Shutsemau wrote: > On x86, page tables are allocated from the buddy allocator and if PG_SIZE > is greater than 4 KB, we need a way to pack multiple page tables into a > single page. We could use the slab allocator for this, but it would > require relocating the page-table metadata out of struct page. Have you looked at the s390/ppc implementations (yes, they're different, no, that sucks)? slab seems like the wrong approach to me. There's a third approach that I've never looked at which is to allocate the larger size, then just use it for N consecutive entries.