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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 1B9DAC4360F for ; Thu, 14 Feb 2019 01:53:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E694921904 for ; Thu, 14 Feb 2019 01:53:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392020AbfBNBxZ (ORCPT ); Wed, 13 Feb 2019 20:53:25 -0500 Received: from mga14.intel.com ([192.55.52.115]:45167 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732776AbfBNBxY (ORCPT ); Wed, 13 Feb 2019 20:53:24 -0500 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 13 Feb 2019 17:53:23 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.58,367,1544515200"; d="scan'208";a="116051781" Received: from iweiny-desk2.sc.intel.com ([10.3.52.157]) by orsmga006.jf.intel.com with ESMTP; 13 Feb 2019 17:53:22 -0800 Date: Wed, 13 Feb 2019 17:53:14 -0800 From: Ira Weiny To: Jason Gunthorpe Cc: Daniel Jordan , akpm@linux-foundation.org, dave@stgolabs.net, jack@suse.cz, cl@linux.com, linux-mm@kvack.org, kvm@vger.kernel.org, kvm-ppc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-fpga@vger.kernel.org, linux-kernel@vger.kernel.org, alex.williamson@redhat.com, paulus@ozlabs.org, benh@kernel.crashing.org, mpe@ellerman.id.au, hao.wu@intel.com, atull@kernel.org, mdf@kernel.org, aik@ozlabs.ru Subject: Re: [PATCH 0/5] use pinned_vm instead of locked_vm to account pinned pages Message-ID: <20190214015314.GB1151@iweiny-DESK2.sc.intel.com> References: <20190211224437.25267-1-daniel.m.jordan@oracle.com> <20190211225447.GN24692@ziepe.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190211225447.GN24692@ziepe.ca> User-Agent: Mutt/1.11.1 (2018-12-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 11, 2019 at 03:54:47PM -0700, Jason Gunthorpe wrote: > On Mon, Feb 11, 2019 at 05:44:32PM -0500, Daniel Jordan wrote: > > > All five of these places, and probably some of Davidlohr's conversions, > > probably want to be collapsed into a common helper in the core mm for > > accounting pinned pages. I tried, and there are several details that > > likely need discussion, so this can be done as a follow-on. > > I've wondered the same.. I'm really thinking this would be a nice way to ensure it gets cleaned up and does not happen again. Also, by moving it to the core we could better manage any user visible changes. >From a high level, pinned is a subset of locked so it seems like we need a 2 sets of helpers. try_increment_locked_vm(...) decrement_locked_vm(...) try_increment_pinned_vm(...) decrement_pinned_vm(...) Where try_increment_pinned_vm() also increments locked_vm... Of course this may end up reverting the improvement of Davidlohr Bueso's atomic work... :-( Furthermore it would seem better (although I don't know if at all possible) if this were accounted for in core calls which tracked them based on how the pages are being used so that drivers can't call try_increment_locked_vm() and then pin the pages... Thus getting the account wrong vs what actually happened. And then in the end we can go back to locked_vm being the value checked against RLIMIT_MEMLOCK. Ira