From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ed1-f72.google.com (mail-ed1-f72.google.com [209.85.208.72]) by kanga.kvack.org (Postfix) with ESMTP id 6B58E6B000C for ; Tue, 7 Aug 2018 10:59:05 -0400 (EDT) Received: by mail-ed1-f72.google.com with SMTP id l16-v6so5243140edq.18 for ; Tue, 07 Aug 2018 07:59:05 -0700 (PDT) Received: from mx1.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id z47-v6si2063860edc.449.2018.08.07.07.59.04 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 07 Aug 2018 07:59:04 -0700 (PDT) Date: Tue, 7 Aug 2018 16:59:00 +0200 From: Michal Hocko Subject: Re: [RFC PATCH 2/3] mm/memory_hotplug: Create __shrink_pages and move it to offline_pages Message-ID: <20180807145900.GH10003@dhcp22.suse.cz> References: <20180807133757.18352-1-osalvador@techadventures.net> <20180807133757.18352-3-osalvador@techadventures.net> <20180807135221.GA3301@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180807135221.GA3301@redhat.com> Sender: owner-linux-mm@kvack.org List-ID: To: Jerome Glisse Cc: osalvador@techadventures.net, akpm@linux-foundation.org, dan.j.williams@intel.com, pasha.tatashin@oracle.com, david@redhat.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 07-08-18 09:52:21, Jerome Glisse wrote: > On Tue, Aug 07, 2018 at 03:37:56PM +0200, osalvador@techadventures.net wrote: > > From: Oscar Salvador > > [...] > > > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c > > index 9bd629944c91..e33555651e46 100644 > > --- a/mm/memory_hotplug.c > > +++ b/mm/memory_hotplug.c > > [...] > > > /** > > * __remove_pages() - remove sections of pages from a zone > > - * @zone: zone from which pages need to be removed > > + * @nid: node which pages belong to > > * @phys_start_pfn: starting pageframe (must be aligned to start of a section) > > * @nr_pages: number of pages to remove (must be multiple of section size) > > * @altmap: alternative device page map or %NULL if default memmap is used > > @@ -548,7 +557,7 @@ static int __remove_section(struct zone *zone, struct mem_section *ms, > > * sure that pages are marked reserved and zones are adjust properly by > > * calling offline_pages(). > > */ > > -int __remove_pages(struct zone *zone, unsigned long phys_start_pfn, > > +int __remove_pages(int nid, unsigned long phys_start_pfn, > > unsigned long nr_pages, struct vmem_altmap *altmap) > > { > > unsigned long i; > > @@ -556,10 +565,9 @@ int __remove_pages(struct zone *zone, unsigned long phys_start_pfn, > > int sections_to_remove, ret = 0; > > > > /* In the ZONE_DEVICE case device driver owns the memory region */ > > - if (is_dev_zone(zone)) { > > - if (altmap) > > - map_offset = vmem_altmap_offset(altmap); > > - } else { > > + if (altmap) > > + map_offset = vmem_altmap_offset(altmap); > > + else { > > This will break ZONE_DEVICE at least for HMM. While i think that > altmap -> ZONE_DEVICE (ie altmap imply ZONE_DEVICE) the reverse > is not true ie ZONE_DEVICE does not necessarily imply altmap. So > with the above changes you change the expected behavior. Could you be more specific what is the expected behavior here? Is this about calling release_mem_region_adjustable? Why does is it not suitable for zone device ranges? -- Michal Hocko SUSE Labs