From: "Roger Pau Monné" <roger.pau@citrix.com> To: Christoph Hellwig <hch@infradead.org> Cc: <linux-kernel@vger.kernel.org>, Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>, David Airlie <airlied@linux.ie>, "Daniel Vetter" <daniel@ffwll.ch>, Boris Ostrovsky <boris.ostrovsky@oracle.com>, Juergen Gross <jgross@suse.com>, Stefano Stabellini <sstabellini@kernel.org>, Dan Carpenter <dan.carpenter@oracle.com>, Wei Liu <wl@xen.org>, "Yan Yankovskyi" <yyankovskyi@gmail.com>, <dri-devel@lists.freedesktop.org>, <xen-devel@lists.xenproject.org>, <linux-mm@kvack.org>, David Hildenbrand <david@redhat.com>, Michal Hocko <mhocko@kernel.org>, Dan Williams <dan.j.williams@intel.com> Subject: Re: [PATCH v4 2/2] xen: add helpers to allocate unpopulated memory Date: Fri, 14 Aug 2020 11:56:29 +0200 [thread overview] Message-ID: <20200814095629.GJ975@Air-de-Roger> (raw) In-Reply-To: <20200814072920.GA6126@infradead.org> 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 + help + Use unpopulated memory ranges in order to create mappings for guest + memory regions, including grants maps and foreign pages. This avoids + having to balloon out RAM regions in order to obtain physical memory + space to create such mappings. endmenu
WARNING: multiple messages have this Message-ID (diff)
From: "Roger Pau Monné" <roger.pau@citrix.com> To: Christoph Hellwig <hch@infradead.org> Cc: Juergen Gross <jgross@suse.com>, Stefano Stabellini <sstabellini@kernel.org>, Wei Liu <wl@xen.org>, Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>, David Airlie <airlied@linux.ie>, Yan Yankovskyi <yyankovskyi@gmail.com>, David Hildenbrand <david@redhat.com>, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Michal Hocko <mhocko@kernel.org>, linux-mm@kvack.org, xen-devel@lists.xenproject.org, Boris Ostrovsky <boris.ostrovsky@oracle.com>, Dan Williams <dan.j.williams@intel.com>, Dan Carpenter <dan.carpenter@oracle.com> Subject: Re: [PATCH v4 2/2] xen: add helpers to allocate unpopulated memory Date: Fri, 14 Aug 2020 11:56:29 +0200 [thread overview] Message-ID: <20200814095629.GJ975@Air-de-Roger> (raw) In-Reply-To: <20200814072920.GA6126@infradead.org> 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 + help + Use unpopulated memory ranges in order to create mappings for guest + memory regions, including grants maps and foreign pages. This avoids + having to balloon out RAM regions in order to obtain physical memory + space to create such mappings. endmenu _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
next prev parent reply other threads:[~2020-08-14 9:56 UTC|newest] Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-08-11 9:44 [PATCH v4 0/2] xen/balloon: fixes for memory hotplug Roger Pau Monne 2020-08-11 9:44 ` Roger Pau Monne 2020-08-11 9:44 ` [PATCH v4 1/2] memremap: rename MEMORY_DEVICE_DEVDAX to MEMORY_DEVICE_GENERIC Roger Pau Monne 2020-08-11 9:44 ` Roger Pau Monne 2020-08-11 9:44 ` Roger Pau Monne 2020-08-11 21:07 ` David Hildenbrand 2020-08-11 21:07 ` David Hildenbrand 2020-08-11 21:07 ` David Hildenbrand 2020-08-20 11:37 ` Roger Pau Monné 2020-08-20 11:37 ` Roger Pau Monné 2020-08-31 10:19 ` Roger Pau Monné 2020-08-31 10:19 ` Roger Pau Monné 2020-08-31 10:19 ` Roger Pau Monné 2020-08-31 20:56 ` Ira Weiny 2020-08-31 20:56 ` Ira Weiny 2020-08-31 19:20 ` Andrew Morton 2020-08-31 19:20 ` Andrew Morton 2020-08-11 9:44 ` [PATCH v4 2/2] xen: add helpers to allocate unpopulated memory Roger Pau Monne 2020-08-11 9:44 ` Roger Pau Monne 2020-08-11 9:44 ` Roger Pau Monne 2020-08-12 7:28 ` Jürgen Groß 2020-08-12 7:28 ` Jürgen Groß 2020-08-12 7:28 ` Jürgen Groß 2020-08-12 7:38 ` Roger Pau Monné 2020-08-12 7:38 ` Roger Pau Monné 2020-08-12 7:38 ` Roger Pau Monné 2020-08-12 18:13 ` kernel test robot 2020-08-12 18:13 ` kernel test robot 2020-08-13 7:33 ` Christoph Hellwig 2020-08-13 7:54 ` Roger Pau Monné 2020-08-13 7:54 ` Roger Pau Monné 2020-08-13 7:54 ` Roger Pau Monné 2020-08-13 9:49 ` Daniel Vetter 2020-08-13 9:49 ` Daniel Vetter 2020-08-13 10:02 ` Roger Pau Monné 2020-08-13 10:02 ` Roger Pau Monné 2020-08-14 7:29 ` Christoph Hellwig 2020-08-14 9:56 ` Roger Pau Monné [this message] 2020-08-14 9:56 ` Roger Pau Monné 2020-08-14 9:56 ` Roger Pau Monné 2020-08-14 10:27 ` Jürgen Groß 2020-08-14 10:27 ` Jürgen Groß 2020-08-14 12:47 ` Roger Pau Monné 2020-08-14 12:47 ` Roger Pau Monné 2020-08-14 12:54 ` Jürgen Groß 2020-08-14 12:54 ` Jürgen Groß 2020-08-14 13:35 ` Roger Pau Monné 2020-08-14 13:35 ` Roger Pau Monné 2020-08-14 13:52 ` Jürgen Groß 2020-08-14 13:52 ` Jürgen Groß
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