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 3D972C0044D for ; Sun, 15 Mar 2020 01:17:33 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id DF685206EB for ; Sun, 15 Mar 2020 01:17:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DF685206EB Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 65F2C6B0005; Sat, 14 Mar 2020 21:17:32 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 5E90C6B0006; Sat, 14 Mar 2020 21:17:32 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4B0B46B0007; Sat, 14 Mar 2020 21:17:32 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0218.hostedemail.com [216.40.44.218]) by kanga.kvack.org (Postfix) with ESMTP id 304BF6B0005 for ; Sat, 14 Mar 2020 21:17:32 -0400 (EDT) Received: from smtpin29.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 0E0D9181AEF15 for ; Sun, 15 Mar 2020 01:17:32 +0000 (UTC) X-FDA: 76595833944.29.burst03_77dbba04c115 X-HE-Tag: burst03_77dbba04c115 X-Filterd-Recvd-Size: 3407 Received: from mga18.intel.com (mga18.intel.com [134.134.136.126]) by imf33.hostedemail.com (Postfix) with ESMTP for ; Sun, 15 Mar 2020 01:17:31 +0000 (UTC) IronPort-SDR: dkax0DJeaTDgFp6dtdX/ZbkQOzysmam4V0Y0aYQqNGbPe+xhaEzZ5sz3uWf1srmgL+bpwsTFcB KfekAPJkhi3w== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Mar 2020 18:17:29 -0700 IronPort-SDR: 6RZRYafgPr/dTqPERjsHs00TLV2/oN1wh7Y98ZQe0lQURHbYBWQTKE2DfWxEh7+0TXgADhre3K 6vvOprMCAkGw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,554,1574150400"; d="scan'208";a="323143854" Received: from mbenhamu-mobl2.ger.corp.intel.com (HELO localhost) ([10.251.177.145]) by orsmga001.jf.intel.com with ESMTP; 14 Mar 2020 18:17:15 -0700 Date: Sun, 15 Mar 2020 03:17:13 +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: <20200315011713.GB208715@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> <20200315002732.GA208715@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200315002732.GA208715@linux.intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo 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 Sun, Mar 15, 2020 at 02:27:46AM +0200, Jarkko Sakkinen wrote: > 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. Ugh, I meant __set_page_dirty/account_page_dirtied/task_io_account_write path :-/ Anyway. /Jarkko