From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt0-f197.google.com (mail-qt0-f197.google.com [209.85.216.197]) by kanga.kvack.org (Postfix) with ESMTP id 14C096B4CC1 for ; Wed, 29 Aug 2018 13:04:42 -0400 (EDT) Received: by mail-qt0-f197.google.com with SMTP id o18-v6so5099952qtm.11 for ; Wed, 29 Aug 2018 10:04:42 -0700 (PDT) Received: from mx1.redhat.com (mx3-rdu2.redhat.com. [66.187.233.73]) by mx.google.com with ESMTPS id 37-v6si4028208qvb.268.2018.08.29.10.04.40 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 29 Aug 2018 10:04:40 -0700 (PDT) Date: Wed, 29 Aug 2018 13:04:35 -0400 From: Jerome Glisse Subject: Re: [RFC v2 0/2] Do not touch pages in remove_memory path Message-ID: <20180829170434.GA3784@redhat.com> References: <20180817154127.28602-1-osalvador@techadventures.net> <20180828114709.GA13859@techadventures.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20180828114709.GA13859@techadventures.net> Sender: owner-linux-mm@kvack.org List-ID: To: Oscar Salvador Cc: akpm@linux-foundation.org, mhocko@suse.com, dan.j.williams@intel.com, david@redhat.com, jonathan.cameron@huawei.com, Pavel.Tatashin@microsoft.com, yasu.isimatu@gmail.com, logang@deltatee.com, dave.jiang@intel.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Oscar Salvador On Tue, Aug 28, 2018 at 01:47:09PM +0200, Oscar Salvador wrote: > On Fri, Aug 17, 2018 at 05:41:25PM +0200, Oscar Salvador wrote: > > From: Oscar Salvador > [...] > > > > The main difficulty I faced here was in regard of HMM/devm, as it really handles > > the hot-add/remove memory particulary, and what is more important, > > also the resources. > > > > I really scratched my head for ideas about how to handle this case, and > > after some fails I came up with the idea that we could check for the > > res->flags. > > > > Memory resources that goes through the "official" memory-hotplug channels > > have the IORESOURCE_SYSTEM_RAM flag. > > This flag is made of (IORESOURCE_MEM|IORESOURCE_SYSRAM). > > > > HMM/devm, on the other hand, request and release the resources > > through devm_request_mem_region/devm_release_mem_region, and > > these resources do not contain the IORESOURCE_SYSRAM flag. > > > > So what I ended up doing is to check for IORESOURCE_SYSRAM > > in release_mem_region_adjustable. > > If we see that a resource does not have such a flag, we know that > > we are dealing with a resource coming from HMM/devm, and so, > > we do not need to do anything as HMM/dev will take care of that part. > > > > Jerome/Dan, now that the merge window is closed, and before sending the RFCv3, could you please check > this and see if you see something that is flagrant wrong? (about devm/HMM) > > If you prefer I can send v3 spliting up even more. > Maybe this will ease the review. > This looks good to me you can add Reviewed-by: Jerome Glisse