From: Rik van Riel <riel@redhat.com> To: Frank Swiderski <fes@google.com> Cc: Rusty Russell <rusty@rustcorp.com.au>, "Michael S. Tsirkin" <mst@redhat.com>, Andrea Arcangeli <aarcange@redhat.com>, virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, mikew@google.com, Ying Han <yinghan@google.com>, Rafael Aquini <aquini@redhat.com> Subject: Re: [PATCH] Add a page cache-backed balloon device driver. Date: Tue, 26 Jun 2012 17:45:41 -0400 [thread overview] Message-ID: <4FEA2D85.60002@redhat.com> (raw) In-Reply-To: <CAK+C7kWKtoYC=1fBQ45RTFfNc3p2PwZbLMOefMTtzOfsqe_k8w@mail.gmail.com> On 06/26/2012 05:31 PM, Frank Swiderski wrote: > On Tue, Jun 26, 2012 at 1:40 PM, Rik van Riel<riel@redhat.com> wrote: >> The code looks good to me, my only worry is the >> code duplication. We now have 5 balloon drivers, >> for 4 hypervisors, all implementing everything >> from scratch... > > Do you have any recommendations on this? I could (I think reasonably > so) modify the existing virtio_balloon.c and have it change behavior > based on a feature bit or other configuration. I'm not sure that > really addresses the root of what you're pointing out--it's still > adding a different implementation, but doing so as an extension of an > existing one. Ideally, I believe we would have two balloon top parts in a guest (one classical balloon, one on the LRU), and four bottom parts (kvm, xen, vmware & s390). That way the virt specific bits of a balloon driver would be essentially a ->balloon_page and ->release_page callback for pages, as well as methods to communicate with the host. All the management of pages, including stuff like putting them on the LRU, or isolating them for migration, would be done with the same common code, regardless of what virt software we are running on. Of course, that is a substantial amount of work and I feel it would be unreasonable to block anyone's code on that kind of thing (especially considering that your code is good), but I do believe the explosion of balloon code is a little worrying.
WARNING: multiple messages have this Message-ID (diff)
From: Rik van Riel <riel@redhat.com> To: Frank Swiderski <fes@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com>, Rafael Aquini <aquini@redhat.com>, kvm@vger.kernel.org, "Michael S. Tsirkin" <mst@redhat.com>, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, Ying Han <yinghan@google.com>, mikew@google.com Subject: Re: [PATCH] Add a page cache-backed balloon device driver. Date: Tue, 26 Jun 2012 17:45:41 -0400 [thread overview] Message-ID: <4FEA2D85.60002@redhat.com> (raw) In-Reply-To: <CAK+C7kWKtoYC=1fBQ45RTFfNc3p2PwZbLMOefMTtzOfsqe_k8w@mail.gmail.com> On 06/26/2012 05:31 PM, Frank Swiderski wrote: > On Tue, Jun 26, 2012 at 1:40 PM, Rik van Riel<riel@redhat.com> wrote: >> The code looks good to me, my only worry is the >> code duplication. We now have 5 balloon drivers, >> for 4 hypervisors, all implementing everything >> from scratch... > > Do you have any recommendations on this? I could (I think reasonably > so) modify the existing virtio_balloon.c and have it change behavior > based on a feature bit or other configuration. I'm not sure that > really addresses the root of what you're pointing out--it's still > adding a different implementation, but doing so as an extension of an > existing one. Ideally, I believe we would have two balloon top parts in a guest (one classical balloon, one on the LRU), and four bottom parts (kvm, xen, vmware & s390). That way the virt specific bits of a balloon driver would be essentially a ->balloon_page and ->release_page callback for pages, as well as methods to communicate with the host. All the management of pages, including stuff like putting them on the LRU, or isolating them for migration, would be done with the same common code, regardless of what virt software we are running on. Of course, that is a substantial amount of work and I feel it would be unreasonable to block anyone's code on that kind of thing (especially considering that your code is good), but I do believe the explosion of balloon code is a little worrying.
next prev parent reply other threads:[~2012-06-26 21:46 UTC|newest] Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top 2012-06-26 20:32 [PATCH] Add a page cache-backed balloon device driver Frank Swiderski 2012-06-26 20:40 ` Rik van Riel 2012-06-26 20:40 ` Rik van Riel 2012-06-26 21:31 ` Frank Swiderski 2012-06-26 21:31 ` Frank Swiderski 2012-06-26 21:45 ` Rik van Riel [this message] 2012-06-26 21:45 ` Rik van Riel 2012-06-26 23:45 ` Frank Swiderski 2012-06-27 9:04 ` Michael S. Tsirkin 2012-06-27 9:04 ` Michael S. Tsirkin 2012-06-26 21:47 ` Michael S. Tsirkin 2012-06-26 21:47 ` Michael S. Tsirkin 2012-06-26 23:21 ` Frank Swiderski 2012-06-26 23:21 ` Frank Swiderski 2012-06-27 9:02 ` Michael S. Tsirkin 2012-06-27 9:02 ` Michael S. Tsirkin 2012-07-02 0:29 ` Rusty Russell 2012-07-02 0:29 ` Rusty Russell 2012-09-03 6:35 ` Paolo Bonzini 2012-09-03 6:35 ` Paolo Bonzini 2012-09-06 1:35 ` Rusty Russell 2012-09-06 1:35 ` Rusty Russell 2012-06-26 21:41 ` Michael S. Tsirkin 2012-06-26 21:41 ` Michael S. Tsirkin 2012-06-27 2:56 ` Rusty Russell 2012-06-27 2:56 ` Rusty Russell 2012-06-27 15:48 ` Frank Swiderski 2012-06-27 15:48 ` Frank Swiderski 2012-06-27 16:06 ` Michael S. Tsirkin 2012-06-27 16:06 ` Michael S. Tsirkin 2012-06-27 16:08 ` Frank Swiderski 2012-06-27 16:08 ` Frank Swiderski 2012-06-27 9:40 ` Amit Shah 2012-06-27 9:40 ` Amit Shah 2012-08-30 8:57 ` Michael S. Tsirkin 2012-08-30 8:57 ` Michael S. Tsirkin 2012-09-03 15:09 ` Avi Kivity 2012-09-03 15:09 ` Avi Kivity 2012-09-10 9:05 ` Michael S. Tsirkin 2012-09-10 9:05 ` Michael S. Tsirkin 2012-09-10 17:37 ` Mike Waychison 2012-09-10 17:37 ` Mike Waychison 2012-09-10 18:04 ` Rik van Riel 2012-09-10 18:04 ` Rik van Riel 2012-09-10 18:29 ` Mike Waychison 2012-09-10 18:29 ` Mike Waychison 2012-09-10 19:59 ` Michael S. Tsirkin 2012-09-10 19:59 ` Michael S. Tsirkin 2012-09-10 19:59 ` Michael S. Tsirkin 2012-09-10 20:49 ` Mike Waychison 2012-09-10 20:49 ` Mike Waychison 2012-09-10 21:10 ` Michael S. Tsirkin 2012-09-10 21:10 ` Michael S. Tsirkin 2012-10-30 15:29 ` Michael S. Tsirkin 2012-10-30 15:29 ` Michael S. Tsirkin 2012-10-30 16:25 ` Mike Waychison 2012-10-30 16:25 ` Mike Waychison 2012-09-12 5:25 ` Rusty Russell 2012-09-12 5:25 ` Rusty Russell 2012-06-26 20:32 Frank Swiderski
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