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=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 D448DC433E1 for ; Fri, 14 Aug 2020 12:54:57 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (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 A7BA82087D for ; Fri, 14 Aug 2020 12:54:57 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A7BA82087D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1k6ZEI-0002k7-6t; Fri, 14 Aug 2020 12:54:42 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1k6ZEH-0002k2-Tn for xen-devel@lists.xenproject.org; Fri, 14 Aug 2020 12:54:41 +0000 X-Inumbo-ID: 7f75ec31-ed60-4299-b292-b33e6de3892b Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id 7f75ec31-ed60-4299-b292-b33e6de3892b; Fri, 14 Aug 2020 12:54:40 +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 EF0B4B039; Fri, 14 Aug 2020 12:55:02 +0000 (UTC) Subject: Re: [PATCH v4 2/2] xen: add helpers to allocate unpopulated memory To: =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= Cc: Christoph Hellwig , 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> <20200814124724.GK975@Air-de-Roger> From: =?UTF-8?B?SsO8cmdlbiBHcm/Dnw==?= Message-ID: Date: Fri, 14 Aug 2020 14:54:38 +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: <20200814124724.GK975@Air-de-Roger> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" On 14.08.20 14:47, Roger Pau Monné wrote: > On Fri, Aug 14, 2020 at 12:27:32PM +0200, Jürgen Groß wrote: >> 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. > > There's also the privcmd and gnt devices which make heavy use of this, > so I'm not sure only selecting by default on XEN_BACKEND is the best > option. I just want to avoid that kernels built for running as Xen guest, but not as dom0, will be forced to select ZONE_DEVICE. As privcmd is dom0-only, this is no problem. In case you are worrying about gnt devices, I'd be fine to switch to default XEN_BACKEND || XEN_GNTDEV 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,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 B11A3C433E1 for ; Fri, 14 Aug 2020 12:54:43 +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 916A4221E2 for ; Fri, 14 Aug 2020 12:54:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 916A4221E2 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 E55DE6EB33; Fri, 14 Aug 2020 12:54:42 +0000 (UTC) Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by gabe.freedesktop.org (Postfix) with ESMTPS id 90A7C6EB33 for ; Fri, 14 Aug 2020 12:54:41 +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 EF0B4B039; Fri, 14 Aug 2020 12:55:02 +0000 (UTC) Subject: Re: [PATCH v4 2/2] xen: add helpers to allocate unpopulated memory To: =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= 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> <20200814124724.GK975@Air-de-Roger> From: =?UTF-8?B?SsO8cmdlbiBHcm/Dnw==?= Message-ID: Date: Fri, 14 Aug 2020 14:54:38 +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: <20200814124724.GK975@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 , Christoph Hellwig , 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" T24gMTQuMDguMjAgMTQ6NDcsIFJvZ2VyIFBhdSBNb25uw6kgd3JvdGU6Cj4gT24gRnJpLCBBdWcg MTQsIDIwMjAgYXQgMTI6Mjc6MzJQTSArMDIwMCwgSsO8cmdlbiBHcm/DnyB3cm90ZToKPj4gT24g MTQuMDguMjAgMTE6NTYsIFJvZ2VyIFBhdSBNb25uw6kgd3JvdGU6Cj4+PiBPbiBGcmksIEF1ZyAx NCwgMjAyMCBhdCAwODoyOToyMEFNICswMTAwLCBDaHJpc3RvcGggSGVsbHdpZyB3cm90ZToKPj4+ PiBPbiBUaHUsIEF1ZyAxMywgMjAyMCBhdCAwOTo1NDoyMEFNICswMjAwLCBSb2dlciBQYXUgTW9u bj8/IHdyb3RlOgo+Pj4+PiBPbiBUaHUsIEF1ZyAxMywgMjAyMCBhdCAwODozMzozN0FNICswMTAw LCBDaHJpc3RvcGggSGVsbHdpZyB3cm90ZToKPj4+Pj4+IE9uIFR1ZSwgQXVnIDExLCAyMDIwIGF0 IDExOjQ0OjQ3QU0gKzAyMDAsIFJvZ2VyIFBhdSBNb25uZSB3cm90ZToKPj4+Pj4+PiBJZiBlbmFi bGVkIChiZWNhdXNlIFpPTkVfREVWSUNFIGlzIHN1cHBvcnRlZCkgdGhlIHVzYWdlIG9mIHRoZSBu ZXcKPj4+Pj4+PiBmdW5jdGlvbmFsaXR5IHVudGFuZ2xlcyBYZW4gYmFsbG9vbiBhbmQgUkFNIGhv dHBsdWcgZnJvbSB0aGUgdXNhZ2Ugb2YKPj4+Pj4+PiB1bnBvcHVsYXRlZCBwaHlzaWNhbCBtZW1v cnkgcmFuZ2VzIHRvIG1hcCBmb3JlaWduIHBhZ2VzLCB3aGljaCBpcyB0aGUKPj4+Pj4+PiBjb3Jy ZWN0IHRoaW5nIHRvIGRvIGluIG9yZGVyIHRvIGF2b2lkIG1hcHBpbmdzIG9mIGZvcmVpZ24gcGFn ZXMgZGVwZW5kCj4+Pj4+Pj4gb24gbWVtb3J5IGhvdHBsdWcuCj4+Pj4+Pgo+Pj4+Pj4gU28gcGxl YXNlIGp1c3Qgc2VsZWN0IFpPTkVfREVWSUNFIGlmIHRoaXMgaXMgc28gbXVjaCBiZXR0ZXIgcmF0 aGVyCj4+Pj4+PiB0aGFuIG1haW50YWluaW5nIHR3byB2YXJpYW50cy4KPj4+Pj4KPj4+Pj4gV2Ug c3RpbGwgbmVlZCB0byBvdGhlciB2YXJpYW50IGZvciBBcm0gYXQgbGVhc3QsIHNvIGJvdGggbmVl ZCB0byBiZQo+Pj4+PiBtYWludGFpbmVkIGFueXdheSwgZXZlbiBpZiB3ZSBmb3JjZSBaT05FX0RF VklDRSBvbiB4ODYuCj4+Pj4KPj4+PiBXZWxsLCBpdCBzdGlsbCByZWFsbHkgaGVscHMgcmVwcm9k dWNhYmlsaXR5IGlmIHlvdSBzdGljayB0byBvbmUKPj4+PiBpbXBsZW1lbnRhdGlvbiBvZiB4ODYu Cj4+Pj4KPj4+PiBUaGUgYWx0ZXJuYXRpdmUgd291bGQgYmUgYW4gZXhwbGljaXQgY29uZmlnIG9w dGlvbiB0byBvcHQgaW50byBpdCwKPj4+PiBidXQganVzdCBnZXR0aW5nIGEgZGlmZmVyZW50IGlt cGxlbWVudGF0aW9uIGJhc2VkIG9uIGEgcmFuZG9tCj4+Pj4ga2VybmVsIG9wdGlvbiBpcyBzdHJh bmdlLgo+Pj4KPj4+IFdvdWxkIGFkZGluZyBzb21ldGhpbmcgbGlrZSB0aGUgY2h1bmsgYmVsb3cg dG8gdGhlIHBhdGNoIGJlIE9LPwo+Pj4KPj4+IC0tLTg8LS0tCj4+PiBkaWZmIC0tZ2l0IGEvZHJp dmVycy94ZW4vS2NvbmZpZyBiL2RyaXZlcnMveGVuL0tjb25maWcKPj4+IGluZGV4IDAxODAyMGI5 MWJhYS4uNWYzMjFhMTMxOWU2IDEwMDY0NAo+Pj4gLS0tIGEvZHJpdmVycy94ZW4vS2NvbmZpZwo+ Pj4gKysrIGIvZHJpdmVycy94ZW4vS2NvbmZpZwo+Pj4gQEAgLTMyOCw3ICszMjgsMTQgQEAgY29u ZmlnIFhFTl9GUk9OVF9QR0RJUl9TSEJVRgo+Pj4gICAgCXRyaXN0YXRlCj4+PiAgICBjb25maWcg WEVOX1VOUE9QVUxBVEVEX0FMTE9DCj4+PiAtCWJvb2wKPj4+IC0JZGVmYXVsdCB5IGlmIFpPTkVf REVWSUNFICYmICFBUk0gJiYgIUFSTTY0Cj4+PiArCWJvb2wgIlVzZSB1bnBvcHVsYXRlZCBtZW1v cnkgcmFuZ2VzIGZvciBndWVzdCBtYXBwaW5ncyIKPj4+ICsJZGVwZW5kcyBvbiBYODYKPj4+ICsJ c2VsZWN0IFpPTkVfREVWSUNFCj4+PiArCWRlZmF1bHQgeQo+Pgo+PiBJJ2QgcmF0aGVyIHVzZSAi ZGVmYXVsdCBYRU5fQkFDS0VORCIgaGVyZSwgYXMgbWFwcGluZ3Mgb2Ygb3RoZXIgZ3Vlc3Qncwo+ PiBtZW1vcnkgaXMgcmFyZWx5IHVzZWQgZm9yIG5vbi1iYWNrZW5kIGd1ZXN0cy4KPiAKPiBUaGVy ZSdzIGFsc28gdGhlIHByaXZjbWQgYW5kIGdudCBkZXZpY2VzIHdoaWNoIG1ha2UgaGVhdnkgdXNl IG9mIHRoaXMsCj4gc28gSSdtIG5vdCBzdXJlIG9ubHkgc2VsZWN0aW5nIGJ5IGRlZmF1bHQgb24g WEVOX0JBQ0tFTkQgaXMgdGhlIGJlc3QKPiBvcHRpb24uCgpJIGp1c3Qgd2FudCB0byBhdm9pZCB0 aGF0IGtlcm5lbHMgYnVpbHQgZm9yIHJ1bm5pbmcgYXMgWGVuIGd1ZXN0LCBidXQKbm90IGFzIGRv bTAsIHdpbGwgYmUgZm9yY2VkIHRvIHNlbGVjdCBaT05FX0RFVklDRS4KCkFzIHByaXZjbWQgaXMg ZG9tMC1vbmx5LCB0aGlzIGlzIG5vIHByb2JsZW0uCgpJbiBjYXNlIHlvdSBhcmUgd29ycnlpbmcg YWJvdXQgZ250IGRldmljZXMsIEknZCBiZSBmaW5lIHRvIHN3aXRjaCB0bwoKZGVmYXVsdCBYRU5f QkFDS0VORCB8fCBYRU5fR05UREVWCgoKSnVlcmdlbgoKX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX18KZHJpLWRldmVsIG1haWxpbmcgbGlzdApkcmktZGV2ZWxA bGlzdHMuZnJlZWRlc2t0b3Aub3JnCmh0dHBzOi8vbGlzdHMuZnJlZWRlc2t0b3Aub3JnL21haWxt YW4vbGlzdGluZm8vZHJpLWRldmVsCg==