From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753614AbdHQVzy (ORCPT ); Thu, 17 Aug 2017 17:55:54 -0400 Received: from mx1.redhat.com ([209.132.183.28]:37488 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753470AbdHQVzw (ORCPT ); Thu, 17 Aug 2017 17:55:52 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com A496137E88 Authentication-Results: ext-mx05.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx05.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=jglisse@redhat.com Date: Thu, 17 Aug 2017 17:55:50 -0400 From: Jerome Glisse To: Andrew Morton Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, John Hubbard , Dan Williams , David Nellans , Balbir Singh Subject: Re: [HMM-v25 00/19] HMM (Heterogeneous Memory Management) v25 Message-ID: <20170817215549.GD2872@redhat.com> References: <20170817000548.32038-1-jglisse@redhat.com> <20170817143916.63fca76e4c1fd841e0afd4cf@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20170817143916.63fca76e4c1fd841e0afd4cf@linux-foundation.org> User-Agent: Mutt/1.8.3 (2017-05-23) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Thu, 17 Aug 2017 21:55:52 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 17, 2017 at 02:39:16PM -0700, Andrew Morton wrote: > On Wed, 16 Aug 2017 20:05:29 -0400 J__r__me Glisse wrote: > > > Heterogeneous Memory Management (HMM) (description and justification) > > The patchset adds 55 kbytes to x86_64's mm/*.o and there doesn't appear > to be any way of avoiding this overhead, or of avoiding whatever > runtime overheads are added. HMM have already been integrated in couple of Red Hat kernel and AFAIK there is no runtime performance issue reported. Thought the RHEL version does not use static key as Dan asked. > > It also adds 18k to arm's mm/*.o and arm doesn't support HMM at all. > > So that's all quite a lot of bloat for systems which get no benefit from > the patchset. What can we do to improve this situation (a lot)? I will look into why object file grow so much on arm. My guess is that the new migrate code is the bulk of that. I can hide the new page migration code behind a kernel configuration flag. Cheers, Jérôme From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-f199.google.com (mail-qk0-f199.google.com [209.85.220.199]) by kanga.kvack.org (Postfix) with ESMTP id 3841E6B025F for ; Thu, 17 Aug 2017 17:55:54 -0400 (EDT) Received: by mail-qk0-f199.google.com with SMTP id o124so38441664qke.9 for ; Thu, 17 Aug 2017 14:55:54 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id k31si3866973qte.266.2017.08.17.14.55.53 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 17 Aug 2017 14:55:53 -0700 (PDT) Date: Thu, 17 Aug 2017 17:55:50 -0400 From: Jerome Glisse Subject: Re: [HMM-v25 00/19] HMM (Heterogeneous Memory Management) v25 Message-ID: <20170817215549.GD2872@redhat.com> References: <20170817000548.32038-1-jglisse@redhat.com> <20170817143916.63fca76e4c1fd841e0afd4cf@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20170817143916.63fca76e4c1fd841e0afd4cf@linux-foundation.org> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, John Hubbard , Dan Williams , David Nellans , Balbir Singh On Thu, Aug 17, 2017 at 02:39:16PM -0700, Andrew Morton wrote: > On Wed, 16 Aug 2017 20:05:29 -0400 J__r__me Glisse wrote: > > > Heterogeneous Memory Management (HMM) (description and justification) > > The patchset adds 55 kbytes to x86_64's mm/*.o and there doesn't appear > to be any way of avoiding this overhead, or of avoiding whatever > runtime overheads are added. HMM have already been integrated in couple of Red Hat kernel and AFAIK there is no runtime performance issue reported. Thought the RHEL version does not use static key as Dan asked. > > It also adds 18k to arm's mm/*.o and arm doesn't support HMM at all. > > So that's all quite a lot of bloat for systems which get no benefit from > the patchset. What can we do to improve this situation (a lot)? I will look into why object file grow so much on arm. My guess is that the new migrate code is the bulk of that. I can hide the new page migration code behind a kernel configuration flag. Cheers, Jerome -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org