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=-9.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 65B2EC433E1 for ; Mon, 27 Jul 2020 08:01:12 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 2615C20672 for ; Mon, 27 Jul 2020 08:01:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="OC3kjwOb" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2615C20672 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id ADB546B0003; Mon, 27 Jul 2020 04:01:11 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A8B656B0007; Mon, 27 Jul 2020 04:01:11 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 97C426B0008; Mon, 27 Jul 2020 04:01:11 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0212.hostedemail.com [216.40.44.212]) by kanga.kvack.org (Postfix) with ESMTP id 82A7A6B0003 for ; Mon, 27 Jul 2020 04:01:11 -0400 (EDT) Received: from smtpin08.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 3F3D21EE6 for ; Mon, 27 Jul 2020 08:01:11 +0000 (UTC) X-FDA: 77083110342.08.mark86_050460626f5f Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin08.hostedemail.com (Postfix) with ESMTP id 12DB01819E773 for ; Mon, 27 Jul 2020 08:01:11 +0000 (UTC) X-HE-Tag: mark86_050460626f5f X-Filterd-Recvd-Size: 9083 Received: from us-smtp-1.mimecast.com (us-smtp-delivery-1.mimecast.com [207.211.31.120]) by imf01.hostedemail.com (Postfix) with ESMTP for ; Mon, 27 Jul 2020 08:01:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1595836869; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=kFPPskvXLtA3OM8boP9HcoOBUPstBcsqpRElLohYglg=; b=OC3kjwObRH6mvMcXyos1zj0fXKqINlEXR++kvJZv43zhXD+ltrenH7e7YtIRY0HkaV3VuG f+2pCXqAyOwHkUizN6uAcHoOXvaf6/PjH0mp8ggknsN0eGMFlkbfBDO0L54juHA/tC4vNt TS/yHYOSNHUt1M6xSK/L53c7Rmae44c= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-233-TfzIlOpdPF6myWxB3Q8wdQ-1; Mon, 27 Jul 2020 04:01:00 -0400 X-MC-Unique: TfzIlOpdPF6myWxB3Q8wdQ-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 782F41DE2; Mon, 27 Jul 2020 08:00:57 +0000 (UTC) Received: from [10.36.114.48] (ovpn-114-48.ams2.redhat.com [10.36.114.48]) by smtp.corp.redhat.com (Postfix) with ESMTP id C535072691; Mon, 27 Jul 2020 08:00:46 +0000 (UTC) Subject: Re: [PATCH v2 4/4] xen: add helpers to allocate unpopulated memory To: Boris Ostrovsky , Roger Pau Monne , linux-kernel@vger.kernel.org Cc: Juergen Gross , Stefano Stabellini , Wei Liu , Oleksandr Andrushchenko , David Airlie , Yan Yankovskyi , dri-devel@lists.freedesktop.org, Michal Hocko , linux-mm@kvack.org, Daniel Vetter , xen-devel@lists.xenproject.org, Dan Williams , Dan Carpenter References: <20200724124241.48208-1-roger.pau@citrix.com> <20200724124241.48208-5-roger.pau@citrix.com> <1778c97f-3a69-8280-141c-879814dd213f@redhat.com> <1fd1d29e-5c10-0c29-0628-b79807f81de6@oracle.com> From: David Hildenbrand Autocrypt: addr=david@redhat.com; prefer-encrypt=mutual; keydata= mQINBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABtCREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT6JAlgEEwEIAEICGwMGCwkIBwMCBhUIAgkKCwQW AgMBAh4BAheAAhkBFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAl8Ox4kFCRKpKXgACgkQTd4Q 9wD/g1oHcA//a6Tj7SBNjFNM1iNhWUo1lxAja0lpSodSnB2g4FCZ4R61SBR4l/psBL73xktp rDHrx4aSpwkRP6Epu6mLvhlfjmkRG4OynJ5HG1gfv7RJJfnUdUM1z5kdS8JBrOhMJS2c/gPf wv1TGRq2XdMPnfY2o0CxRqpcLkx4vBODvJGl2mQyJF/gPepdDfcT8/PY9BJ7FL6Hrq1gnAo4 3Iv9qV0JiT2wmZciNyYQhmA1V6dyTRiQ4YAc31zOo2IM+xisPzeSHgw3ONY/XhYvfZ9r7W1l pNQdc2G+o4Di9NPFHQQhDw3YTRR1opJaTlRDzxYxzU6ZnUUBghxt9cwUWTpfCktkMZiPSDGd KgQBjnweV2jw9UOTxjb4LXqDjmSNkjDdQUOU69jGMUXgihvo4zhYcMX8F5gWdRtMR7DzW/YE BgVcyxNkMIXoY1aYj6npHYiNQesQlqjU6azjbH70/SXKM5tNRplgW8TNprMDuntdvV9wNkFs 9TyM02V5aWxFfI42+aivc4KEw69SE9KXwC7FSf5wXzuTot97N9Phj/Z3+jx443jo2NR34XgF 89cct7wJMjOF7bBefo0fPPZQuIma0Zym71cP61OP/i11ahNye6HGKfxGCOcs5wW9kRQEk8P9 M/k2wt3mt/fCQnuP/mWutNPt95w9wSsUyATLmtNrwccz63W5Ag0EVcufkQEQAOfX3n0g0fZz Bgm/S2zF/kxQKCEKP8ID+Vz8sy2GpDvveBq4H2Y34XWsT1zLJdvqPI4af4ZSMxuerWjXbVWb T6d4odQIG0fKx4F8NccDqbgHeZRNajXeeJ3R7gAzvWvQNLz4piHrO/B4tf8svmRBL0ZB5P5A 2uhdwLU3NZuK22zpNn4is87BPWF8HhY0L5fafgDMOqnf4guJVJPYNPhUFzXUbPqOKOkL8ojk CXxkOFHAbjstSK5Ca3fKquY3rdX3DNo+EL7FvAiw1mUtS+5GeYE+RMnDCsVFm/C7kY8c2d0G NWkB9pJM5+mnIoFNxy7YBcldYATVeOHoY4LyaUWNnAvFYWp08dHWfZo9WCiJMuTfgtH9tc75 7QanMVdPt6fDK8UUXIBLQ2TWr/sQKE9xtFuEmoQGlE1l6bGaDnnMLcYu+Asp3kDT0w4zYGsx 5r6XQVRH4+5N6eHZiaeYtFOujp5n+pjBaQK7wUUjDilPQ5QMzIuCL4YjVoylWiBNknvQWBXS lQCWmavOT9sttGQXdPCC5ynI+1ymZC1ORZKANLnRAb0NH/UCzcsstw2TAkFnMEbo9Zu9w7Kv AxBQXWeXhJI9XQssfrf4Gusdqx8nPEpfOqCtbbwJMATbHyqLt7/oz/5deGuwxgb65pWIzufa N7eop7uh+6bezi+rugUI+w6DABEBAAGJAjwEGAEIACYCGwwWIQQb2cqtc1xMOkYN/MpN3hD3 AP+DWgUCXw7HsgUJEqkpoQAKCRBN3hD3AP+DWrrpD/4qS3dyVRxDcDHIlmguXjC1Q5tZTwNB boaBTPHSy/Nksu0eY7x6HfQJ3xajVH32Ms6t1trDQmPx2iP5+7iDsb7OKAb5eOS8h+BEBDeq 3ecsQDv0fFJOA9ag5O3LLNk+3x3q7e0uo06XMaY7UHS341ozXUUI7wC7iKfoUTv03iO9El5f XpNMx/YrIMduZ2+nd9Di7o5+KIwlb2mAB9sTNHdMrXesX8eBL6T9b+MZJk+mZuPxKNVfEQMQ a5SxUEADIPQTPNvBewdeI80yeOCrN+Zzwy/Mrx9EPeu59Y5vSJOx/z6OUImD/GhX7Xvkt3kq Er5KTrJz3++B6SH9pum9PuoE/k+nntJkNMmQpR4MCBaV/J9gIOPGodDKnjdng+mXliF3Ptu6 3oxc2RCyGzTlxyMwuc2U5Q7KtUNTdDe8T0uE+9b8BLMVQDDfJjqY0VVqSUwImzTDLX9S4g/8 kC4HRcclk8hpyhY2jKGluZO0awwTIMgVEzmTyBphDg/Gx7dZU1Xf8HFuE+UZ5UDHDTnwgv7E th6RC9+WrhDNspZ9fJjKWRbveQgUFCpe1sa77LAw+XFrKmBHXp9ZVIe90RMe2tRL06BGiRZr jPrnvUsUUsjRoRNJjKKA/REq+sAnhkNPPZ/NNMjaZ5b8Tovi8C0tmxiCHaQYqj7G2rgnT0kt WNyWQQ== Organization: Red Hat GmbH Message-ID: <6bd01b60-2625-c46e-f9ff-95247700a8cc@redhat.com> Date: Mon, 27 Jul 2020 10:00:44 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.9.0 MIME-Version: 1.0 In-Reply-To: <1fd1d29e-5c10-0c29-0628-b79807f81de6@oracle.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Rspamd-Queue-Id: 12DB01819E773 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam02 Content-Transfer-Encoding: quoted-printable 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 24.07.20 18:36, Boris Ostrovsky wrote: > On 7/24/20 10:34 AM, David Hildenbrand wrote: >> CCing Dan >> >> On 24.07.20 14:42, Roger Pau Monne wrote: >>> diff --git a/drivers/xen/unpopulated-alloc.c b/drivers/xen/unpopulate= d-alloc.c >>> new file mode 100644 >>> index 000000000000..aaa91cefbbf9 >>> --- /dev/null >>> +++ b/drivers/xen/unpopulated-alloc.c >>> @@ -0,0 +1,222 @@ >=20 >=20 >=20 >>> + */ >>> + >>> +#include >>> +#include >>> +#include >>> +#include >>> +#include >>> +#include >>> + >>> +#include >>> + >>> +#include >>> +#include >>> + >>> +static DEFINE_MUTEX(lock); >>> +static LIST_HEAD(list); >>> +static unsigned int count; >>> + >>> +static int fill(unsigned int nr_pages) >=20 >=20 > Less generic names? How about=C2=A0 list_lock, pg_list, pg_count, > fill_pglist()? (But these are bad too, so maybe you can come up with > something better) >=20 >=20 >>> +{ >>> + struct dev_pagemap *pgmap; >>> + void *vaddr; >>> + unsigned int i, alloc_pages =3D round_up(nr_pages, PAGES_PER_SECTIO= N); >>> + int nid, ret; >>> + >>> + pgmap =3D kzalloc(sizeof(*pgmap), GFP_KERNEL); >>> + if (!pgmap) >>> + return -ENOMEM; >>> + >>> + pgmap->type =3D MEMORY_DEVICE_DEVDAX; >>> + pgmap->res.name =3D "XEN SCRATCH"; >=20 >=20 > Typically iomem resources only capitalize first letters. >=20 >=20 >>> + pgmap->res.flags =3D IORESOURCE_MEM | IORESOURCE_BUSY; >>> + >>> + ret =3D allocate_resource(&iomem_resource, &pgmap->res, >>> + alloc_pages * PAGE_SIZE, 0, -1, >>> + PAGES_PER_SECTION * PAGE_SIZE, NULL, NULL); >=20 >=20 > Are we not going to end up with a whole bunch of "Xen scratch" resource > ranges for each miss in the page list? Or do we expect them to get merg= ed? >=20 AFAIK, no resources will get merged (and it's in the general case not safe to do). The old approach (add_memory_resource()) will end up with the same situation ("Xen Scratch" vs. "System RAM") one new resource per added memory block/section. FWIW, I am looking into merging selected resources in the context of virtio-mem _after_ adding succeeded (not directly when adding the resource to the tree). Interface might look something like void merge_child_mem_resources(struct resource *parent, const char *name)= ; So I can, for example, trigger merging of all "System RAM (virtio_mem)" resources, that are located under a device node (e.g., "virtio0"). I also thought about tagging each mergeable resource via something like "IORESOURCE_MERGEABLE" - whereby the user agrees that it does not hold any pointers to such a resource. But I don't see yet a copelling reason to sacrifice space for a new flag. So with this in place, this code could call once adding succeeded merge_child_mem_resources(&iomem_resource, "Xen Scratch"); --=20 Thanks, David / dhildenb