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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id C6631C433F5 for ; Tue, 18 Jan 2022 21:41:51 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 3557D6B0072; Tue, 18 Jan 2022 16:41:51 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 304706B0073; Tue, 18 Jan 2022 16:41:51 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1F2FE6B0074; Tue, 18 Jan 2022 16:41:51 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0217.hostedemail.com [216.40.44.217]) by kanga.kvack.org (Postfix) with ESMTP id 0FAE06B0072 for ; Tue, 18 Jan 2022 16:41:51 -0500 (EST) Received: from smtpin06.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id C93688249980 for ; Tue, 18 Jan 2022 21:41:50 +0000 (UTC) X-FDA: 79044730380.06.19A660D Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by imf10.hostedemail.com (Postfix) with ESMTP id E90D5C0002 for ; Tue, 18 Jan 2022 21:41:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1642542110; x=1674078110; h=to:references:from:subject:message-id:date:mime-version: in-reply-to:content-transfer-encoding; bh=82vTBvRwSqUF/1jlnm0X+PDvb31yaJjN2/Eq92CGb1E=; b=YEUsXtXE1ViI7X12HxqoEff/J6J6WK6VdCrPeIlGRA/VPM4j1IqcGO2o 5suOuqVakP8D3AMasMQyebZT6q43HDnBz4djsd7q84R2E8cBUXJ8mvxe7 akLPxVPLMJQGBiEYPbW6GM29SYxx0Zz26OewfEHlaCp3N+Ky3/SppqEob KYdoCAHWUyBTxS3hnFhdg5/falDc7qhQMwxC8P2yelm6x3wba5kjqYrHd BDQkBOFwe8/SkmQTU3iA2bs5G1hB0RrxXjXSjgfsjJJ3dSRLyiqOO+wD4 qymmnJHVYGxBzcAVocpc8+wQ0RKdEosIxgdTP3Ec9KAUalJJkU4NCeQTG g==; X-IronPort-AV: E=McAfee;i="6200,9189,10231"; a="331272517" X-IronPort-AV: E=Sophos;i="5.88,298,1635231600"; d="scan'208";a="331272517" Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga105.fm.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 X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: E90D5C0002 X-Stat-Signature: 8wtkcihxupuun81xue8cxcy1qh8xohbf Authentication-Results: imf10.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=YEUsXtXE; dmarc=pass (policy=none) header.from=intel.com; spf=none (imf10.hostedemail.com: domain of dave.hansen@intel.com has no SPF policy when checking 192.55.52.43) smtp.mailfrom=dave.hansen@intel.com X-HE-Tag: 1642542105-975043 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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?