From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3C292C433F5 for ; Tue, 18 Jan 2022 21:41:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343960AbiARVlr (ORCPT ); Tue, 18 Jan 2022 16:41:47 -0500 Received: from mga07.intel.com ([134.134.136.100]:64795 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233335AbiARVlo (ORCPT ); Tue, 18 Jan 2022 16:41:44 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1642542104; x=1674078104; h=to:references:from:subject:message-id:date:mime-version: in-reply-to:content-transfer-encoding; bh=82vTBvRwSqUF/1jlnm0X+PDvb31yaJjN2/Eq92CGb1E=; b=NPxZPSFN07r7frgSkuWXnjdJLmsvJzqiYo6XlUnpgF4t4FiRXInkTSe8 mMZEESwpqpTfctOmm57+SWhCHrEhh7JFnpQYyxAHgiNWkEfFBlVTRLahg T6dT7496lffzu+8t0UEx68DQbdTw3GP3X+Xckcx8mILW6QDAQk9B71q94 Yxt3gYE2ytSMNqE3JwRRBEUivInMDmyJZtATZDT2toJJ7GJ8h4/fTBi3T XEx6D5oa8LEJ4DOQIKuvaUFGkE3ROKE4i/S9L4lb8oCDYQjqmBQFqO61v 4wXfOBmPcpPZQYe53itRAXmmkr55HyT4cP72eRE46S5dQaLvxTSSSiUVg w==; X-IronPort-AV: E=McAfee;i="6200,9189,10231"; a="308262826" X-IronPort-AV: E=Sophos;i="5.88,298,1635231600"; d="scan'208";a="308262826" Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Jan 2022 13:41:44 -0800 X-IronPort-AV: E=Sophos;i="5.88,298,1635231600"; d="scan'208";a="764726247" Received: from ssrikan2-mobl2.amr.corp.intel.com (HELO [10.209.52.128]) ([10.209.52.128]) by fmsmga006-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Jan 2022 13:41:43 -0800 To: Khalid Aziz , akpm@linux-foundation.org, willy@infradead.org, longpeng2@huawei.com, arnd@arndb.de, dave.hansen@linux.intel.com, david@redhat.com, rppt@kernel.org, surenb@google.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org References: From: Dave Hansen Subject: Re: [RFC PATCH 0/6] Add support for shared PTEs across processes Message-ID: Date: Tue, 18 Jan 2022 13:41:40 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.14.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 1/18/22 1:19 PM, Khalid Aziz wrote: > - Starting address must be aligned to pgdir size (512GB on x86_64) How does this work on systems with 5-level paging where a top-level page table entry covers 256TB? Is the alignment requirement 512GB or 256TB? How does userspace figure out which alignment requirement it is subject to?