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=-8.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 D5FDFC433E3 for ; Fri, 14 Aug 2020 10:27:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BE44720781 for ; Fri, 14 Aug 2020 10:27:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726968AbgHNK1g (ORCPT ); Fri, 14 Aug 2020 06:27:36 -0400 Received: from mx2.suse.de ([195.135.220.15]:54728 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726820AbgHNK1g (ORCPT ); Fri, 14 Aug 2020 06:27:36 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 5DBB0AF8F; Fri, 14 Aug 2020 10:27:56 +0000 (UTC) Subject: Re: [PATCH v4 2/2] xen: add helpers to allocate unpopulated memory To: =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= , Christoph Hellwig Cc: linux-kernel@vger.kernel.org, Oleksandr Andrushchenko , David Airlie , Daniel Vetter , Boris Ostrovsky , Stefano Stabellini , Dan Carpenter , Wei Liu , Yan Yankovskyi , dri-devel@lists.freedesktop.org, xen-devel@lists.xenproject.org, linux-mm@kvack.org, David Hildenbrand , Michal Hocko , Dan Williams References: <20200811094447.31208-1-roger.pau@citrix.com> <20200811094447.31208-3-roger.pau@citrix.com> <20200813073337.GA16160@infradead.org> <20200813075420.GC975@Air-de-Roger> <20200814072920.GA6126@infradead.org> <20200814095629.GJ975@Air-de-Roger> From: =?UTF-8?B?SsO8cmdlbiBHcm/Dnw==?= Message-ID: Date: Fri, 14 Aug 2020 12:27:32 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20200814095629.GJ975@Air-de-Roger> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 14.08.20 11:56, Roger Pau Monné wrote: > On Fri, Aug 14, 2020 at 08:29:20AM +0100, Christoph Hellwig wrote: >> On Thu, Aug 13, 2020 at 09:54:20AM +0200, Roger Pau Monn?? wrote: >>> On Thu, Aug 13, 2020 at 08:33:37AM +0100, Christoph Hellwig wrote: >>>> On Tue, Aug 11, 2020 at 11:44:47AM +0200, Roger Pau Monne wrote: >>>>> If enabled (because ZONE_DEVICE is supported) the usage of the new >>>>> functionality untangles Xen balloon and RAM hotplug from the usage of >>>>> unpopulated physical memory ranges to map foreign pages, which is the >>>>> correct thing to do in order to avoid mappings of foreign pages depend >>>>> on memory hotplug. >>>> >>>> So please just select ZONE_DEVICE if this is so much better rather >>>> than maintaining two variants. >>> >>> We still need to other variant for Arm at least, so both need to be >>> maintained anyway, even if we force ZONE_DEVICE on x86. >> >> Well, it still really helps reproducability if you stick to one >> implementation of x86. >> >> The alternative would be an explicit config option to opt into it, >> but just getting a different implementation based on a random >> kernel option is strange. > > Would adding something like the chunk below to the patch be OK? > > ---8<--- > diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig > index 018020b91baa..5f321a1319e6 100644 > --- a/drivers/xen/Kconfig > +++ b/drivers/xen/Kconfig > @@ -328,7 +328,14 @@ config XEN_FRONT_PGDIR_SHBUF > tristate > > config XEN_UNPOPULATED_ALLOC > - bool > - default y if ZONE_DEVICE && !ARM && !ARM64 > + bool "Use unpopulated memory ranges for guest mappings" > + depends on X86 > + select ZONE_DEVICE > + default y I'd rather use "default XEN_BACKEND" here, as mappings of other guest's memory is rarely used for non-backend guests. Juergen 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=-8.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 09D80C433E1 for ; Fri, 14 Aug 2020 10:27:39 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id BAFD9207DA for ; Fri, 14 Aug 2020 10:27:38 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BAFD9207DA Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 4B2536EB27; Fri, 14 Aug 2020 10:27:37 +0000 (UTC) Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by gabe.freedesktop.org (Postfix) with ESMTPS id 50E0C6EB27 for ; Fri, 14 Aug 2020 10:27:35 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 5DBB0AF8F; Fri, 14 Aug 2020 10:27:56 +0000 (UTC) Subject: Re: [PATCH v4 2/2] xen: add helpers to allocate unpopulated memory To: =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= , Christoph Hellwig References: <20200811094447.31208-1-roger.pau@citrix.com> <20200811094447.31208-3-roger.pau@citrix.com> <20200813073337.GA16160@infradead.org> <20200813075420.GC975@Air-de-Roger> <20200814072920.GA6126@infradead.org> <20200814095629.GJ975@Air-de-Roger> From: =?UTF-8?B?SsO8cmdlbiBHcm/Dnw==?= Message-ID: Date: Fri, 14 Aug 2020 12:27:32 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20200814095629.GJ975@Air-de-Roger> Content-Language: en-US X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Stefano Stabellini , Wei Liu , Oleksandr Andrushchenko , David Airlie , Yan Yankovskyi , David Hildenbrand , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Michal Hocko , linux-mm@kvack.org, xen-devel@lists.xenproject.org, Boris Ostrovsky , Dan Williams , Dan Carpenter Content-Transfer-Encoding: base64 Content-Type: text/plain; charset="utf-8"; Format="flowed" Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" T24gMTQuMDguMjAgMTE6NTYsIFJvZ2VyIFBhdSBNb25uw6kgd3JvdGU6Cj4gT24gRnJpLCBBdWcg MTQsIDIwMjAgYXQgMDg6Mjk6MjBBTSArMDEwMCwgQ2hyaXN0b3BoIEhlbGx3aWcgd3JvdGU6Cj4+ IE9uIFRodSwgQXVnIDEzLCAyMDIwIGF0IDA5OjU0OjIwQU0gKzAyMDAsIFJvZ2VyIFBhdSBNb25u Pz8gd3JvdGU6Cj4+PiBPbiBUaHUsIEF1ZyAxMywgMjAyMCBhdCAwODozMzozN0FNICswMTAwLCBD aHJpc3RvcGggSGVsbHdpZyB3cm90ZToKPj4+PiBPbiBUdWUsIEF1ZyAxMSwgMjAyMCBhdCAxMTo0 NDo0N0FNICswMjAwLCBSb2dlciBQYXUgTW9ubmUgd3JvdGU6Cj4+Pj4+IElmIGVuYWJsZWQgKGJl Y2F1c2UgWk9ORV9ERVZJQ0UgaXMgc3VwcG9ydGVkKSB0aGUgdXNhZ2Ugb2YgdGhlIG5ldwo+Pj4+ PiBmdW5jdGlvbmFsaXR5IHVudGFuZ2xlcyBYZW4gYmFsbG9vbiBhbmQgUkFNIGhvdHBsdWcgZnJv bSB0aGUgdXNhZ2Ugb2YKPj4+Pj4gdW5wb3B1bGF0ZWQgcGh5c2ljYWwgbWVtb3J5IHJhbmdlcyB0 byBtYXAgZm9yZWlnbiBwYWdlcywgd2hpY2ggaXMgdGhlCj4+Pj4+IGNvcnJlY3QgdGhpbmcgdG8g ZG8gaW4gb3JkZXIgdG8gYXZvaWQgbWFwcGluZ3Mgb2YgZm9yZWlnbiBwYWdlcyBkZXBlbmQKPj4+ Pj4gb24gbWVtb3J5IGhvdHBsdWcuCj4+Pj4KPj4+PiBTbyBwbGVhc2UganVzdCBzZWxlY3QgWk9O RV9ERVZJQ0UgaWYgdGhpcyBpcyBzbyBtdWNoIGJldHRlciByYXRoZXIKPj4+PiB0aGFuIG1haW50 YWluaW5nIHR3byB2YXJpYW50cy4KPj4+Cj4+PiBXZSBzdGlsbCBuZWVkIHRvIG90aGVyIHZhcmlh bnQgZm9yIEFybSBhdCBsZWFzdCwgc28gYm90aCBuZWVkIHRvIGJlCj4+PiBtYWludGFpbmVkIGFu eXdheSwgZXZlbiBpZiB3ZSBmb3JjZSBaT05FX0RFVklDRSBvbiB4ODYuCj4+Cj4+IFdlbGwsIGl0 IHN0aWxsIHJlYWxseSBoZWxwcyByZXByb2R1Y2FiaWxpdHkgaWYgeW91IHN0aWNrIHRvIG9uZQo+ PiBpbXBsZW1lbnRhdGlvbiBvZiB4ODYuCj4+Cj4+IFRoZSBhbHRlcm5hdGl2ZSB3b3VsZCBiZSBh biBleHBsaWNpdCBjb25maWcgb3B0aW9uIHRvIG9wdCBpbnRvIGl0LAo+PiBidXQganVzdCBnZXR0 aW5nIGEgZGlmZmVyZW50IGltcGxlbWVudGF0aW9uIGJhc2VkIG9uIGEgcmFuZG9tCj4+IGtlcm5l bCBvcHRpb24gaXMgc3RyYW5nZS4KPiAKPiBXb3VsZCBhZGRpbmcgc29tZXRoaW5nIGxpa2UgdGhl IGNodW5rIGJlbG93IHRvIHRoZSBwYXRjaCBiZSBPSz8KPiAKPiAtLS04PC0tLQo+IGRpZmYgLS1n aXQgYS9kcml2ZXJzL3hlbi9LY29uZmlnIGIvZHJpdmVycy94ZW4vS2NvbmZpZwo+IGluZGV4IDAx ODAyMGI5MWJhYS4uNWYzMjFhMTMxOWU2IDEwMDY0NAo+IC0tLSBhL2RyaXZlcnMveGVuL0tjb25m aWcKPiArKysgYi9kcml2ZXJzL3hlbi9LY29uZmlnCj4gQEAgLTMyOCw3ICszMjgsMTQgQEAgY29u ZmlnIFhFTl9GUk9OVF9QR0RJUl9TSEJVRgo+ICAgCXRyaXN0YXRlCj4gICAKPiAgIGNvbmZpZyBY RU5fVU5QT1BVTEFURURfQUxMT0MKPiAtCWJvb2wKPiAtCWRlZmF1bHQgeSBpZiBaT05FX0RFVklD RSAmJiAhQVJNICYmICFBUk02NAo+ICsJYm9vbCAiVXNlIHVucG9wdWxhdGVkIG1lbW9yeSByYW5n ZXMgZm9yIGd1ZXN0IG1hcHBpbmdzIgo+ICsJZGVwZW5kcyBvbiBYODYKPiArCXNlbGVjdCBaT05F X0RFVklDRQo+ICsJZGVmYXVsdCB5CgpJJ2QgcmF0aGVyIHVzZSAiZGVmYXVsdCBYRU5fQkFDS0VO RCIgaGVyZSwgYXMgbWFwcGluZ3Mgb2Ygb3RoZXIgZ3Vlc3QncwptZW1vcnkgaXMgcmFyZWx5IHVz ZWQgZm9yIG5vbi1iYWNrZW5kIGd1ZXN0cy4KCgpKdWVyZ2VuCgpfX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fXwpkcmktZGV2ZWwgbWFpbGluZyBsaXN0CmRyaS1k ZXZlbEBsaXN0cy5mcmVlZGVza3RvcC5vcmcKaHR0cHM6Ly9saXN0cy5mcmVlZGVza3RvcC5vcmcv bWFpbG1hbi9saXN0aW5mby9kcmktZGV2ZWwK