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 X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 45E96C0044D for ; Sun, 15 Mar 2020 01:49:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 14B5F206D5 for ; Sun, 15 Mar 2020 01:49:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726668AbgCOBtV (ORCPT ); Sat, 14 Mar 2020 21:49:21 -0400 Received: from mga04.intel.com ([192.55.52.120]:26789 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726628AbgCOBtV (ORCPT ); Sat, 14 Mar 2020 21:49:21 -0400 IronPort-SDR: YaUreDnd0I1VR/dU7zKQ12apw1SgOSuE96kD1DFzTZip26genzsHH/0XhXWGFCw1Z83xuokpSC CgKyA8z4XypA== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Mar 2020 17:27:45 -0700 IronPort-SDR: 8yK2ll5Tu4V2XpSyStMwsKuKMJf0wdmFBl8nTiWCOzNbqbUn8nz0p9qbL1AUV4PRL72Z+dYBQx 6skQKLPj9qVg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,554,1574150400"; d="scan'208";a="442852835" Received: from mbenhamu-mobl2.ger.corp.intel.com (HELO localhost) ([10.251.177.145]) by fmsmga005.fm.intel.com with ESMTP; 14 Mar 2020 17:27:33 -0700 Date: Sun, 15 Mar 2020 02:27:32 +0200 From: Jarkko Sakkinen To: Sean Christopherson Cc: linux-kernel@vger.kernel.org, x86@kernel.org, linux-sgx@vger.kernel.org, akpm@linux-foundation.org, dave.hansen@intel.com, nhorman@redhat.com, npmccallum@redhat.com, haitao.huang@intel.com, andriy.shevchenko@linux.intel.com, tglx@linutronix.de, kai.svahn@intel.com, bp@alien8.de, josh@joshtriplett.org, luto@kernel.org, kai.huang@intel.com, rientjes@google.com, cedric.xing@intel.com, puiterwijk@redhat.com, linux-mm@kvack.org, Ismo Puustinen , Mark Shanahan , Mikko Ylinen , Derek Bombien Subject: Re: [PATCH v28 16/22] x86/sgx: Add a page reclaimer Message-ID: <20200315002732.GA208715@linux.intel.com> References: <20200303233609.713348-1-jarkko.sakkinen@linux.intel.com> <20200303233609.713348-17-jarkko.sakkinen@linux.intel.com> <20200305190354.GK11500@linux.intel.com> <20200306184702.GD7472@linux.intel.com> <20200312183824.GB26453@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200312183824.GB26453@linux.intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Sender: linux-sgx-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org On Thu, Mar 12, 2020 at 11:38:24AM -0700, Sean Christopherson wrote: > On Fri, Mar 06, 2020 at 08:47:02PM +0200, Jarkko Sakkinen wrote: > > On Thu, Mar 05, 2020 at 11:03:54AM -0800, Sean Christopherson wrote: > > > We've also discussed taking a file descriptor to hold the backing, but > > > unless I'm misreading the pagecache code, that doesn't solve the incorrect > > > accounting problem because the current task, i.e. evicting task, would be > > > charged. In other words, whether the backing is kernel or user controlled > > > is purely an ABI question. > > > > Even if the file is owned by a different process the account happens > > to "current"? > > Yes. Which makes sense as files do not have a 1:1 association with tasks. Yeah, that makes sense. Looking at mm/memory.c. Looking at finish_fault/alloc_set_pte/inc_mm_counter_fast code path that is also what happens. /Jarkko