From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752092AbdARPbB (ORCPT ); Wed, 18 Jan 2017 10:31:01 -0500 Received: from mx1.redhat.com ([209.132.183.28]:33630 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751568AbdARPa7 (ORCPT ); Wed, 18 Jan 2017 10:30:59 -0500 Date: Wed, 18 Jan 2017 17:30:56 +0200 From: "Michael S. Tsirkin" To: "Li, Liang Z" Cc: "kvm@vger.kernel.org" , "virtio-dev@lists.oasis-open.org" , "qemu-devel@nongnu.org" , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "virtualization@lists.linux-foundation.org" , "amit.shah@redhat.com" , "Hansen, Dave" , "cornelia.huck@de.ibm.com" , "pbonzini@redhat.com" , "david@redhat.com" , "aarcange@redhat.com" , "dgilbert@redhat.com" , "quintela@redhat.com" Subject: Re: [virtio-dev] Re: [PATCH v6 kernel 2/5] virtio-balloon: define new feature bit and head struct Message-ID: <20170118173025-mutt-send-email-mst@kernel.org> References: <1482303148-22059-1-git-send-email-liang.z.li@intel.com> <1482303148-22059-3-git-send-email-liang.z.li@intel.com> <20170112185719-mutt-send-email-mst@kernel.org> <20170117210845-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Wed, 18 Jan 2017 15:30:59 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 18, 2017 at 01:55:12AM +0000, Li, Liang Z wrote: > > Sent: Wednesday, January 18, 2017 3:11 AM > > To: Li, Liang Z > > Cc: kvm@vger.kernel.org; virtio-dev@lists.oasis-open.org; qemu- > > devel@nongnu.org; linux-mm@kvack.org; linux-kernel@vger.kernel.org; > > virtualization@lists.linux-foundation.org; amit.shah@redhat.com; Hansen, > > Dave; cornelia.huck@de.ibm.com; pbonzini@redhat.com; > > david@redhat.com; aarcange@redhat.com; dgilbert@redhat.com; > > quintela@redhat.com > > Subject: Re: [virtio-dev] Re: [PATCH v6 kernel 2/5] virtio-balloon: define new > > feature bit and head struct > > > > On Fri, Jan 13, 2017 at 09:24:22AM +0000, Li, Liang Z wrote: > > > > On Wed, Dec 21, 2016 at 02:52:25PM +0800, Liang Li wrote: > > > > > Add a new feature which supports sending the page information with > > > > > range array. The current implementation uses PFNs array, which is > > > > > not very efficient. Using ranges can improve the performance of > > > > > inflating/deflating significantly. > > > > > > > > > > Signed-off-by: Liang Li > > > > > Cc: Michael S. Tsirkin > > > > > Cc: Paolo Bonzini > > > > > Cc: Cornelia Huck > > > > > Cc: Amit Shah > > > > > Cc: Dave Hansen > > > > > Cc: Andrea Arcangeli > > > > > Cc: David Hildenbrand > > > > > --- > > > > > include/uapi/linux/virtio_balloon.h | 12 ++++++++++++ > > > > > 1 file changed, 12 insertions(+) > > > > > > > > > > diff --git a/include/uapi/linux/virtio_balloon.h > > > > > b/include/uapi/linux/virtio_balloon.h > > > > > index 343d7dd..2f850bf 100644 > > > > > --- a/include/uapi/linux/virtio_balloon.h > > > > > +++ b/include/uapi/linux/virtio_balloon.h > > > > > @@ -34,10 +34,14 @@ > > > > > #define VIRTIO_BALLOON_F_MUST_TELL_HOST 0 /* Tell before > > > > reclaiming pages */ > > > > > #define VIRTIO_BALLOON_F_STATS_VQ 1 /* Memory Stats virtqueue > > > > */ > > > > > #define VIRTIO_BALLOON_F_DEFLATE_ON_OOM 2 /* Deflate > > balloon > > > > on OOM */ > > > > > +#define VIRTIO_BALLOON_F_PAGE_RANGE 3 /* Send page info > > > > with ranges */ > > > > > > > > > > /* Size of a PFN in the balloon interface. */ #define > > > > > VIRTIO_BALLOON_PFN_SHIFT 12 > > > > > > > > > > +/* Bits width for the length of the pfn range */ > > > > > > > > What does this mean? Couldn't figure it out. > > > > > > > > > +#define VIRTIO_BALLOON_NR_PFN_BITS 12 > > > > > + > > > > > struct virtio_balloon_config { > > > > > /* Number of pages host wants Guest to give up. */ > > > > > __u32 num_pages; > > > > > @@ -82,4 +86,12 @@ struct virtio_balloon_stat { > > > > > __virtio64 val; > > > > > } __attribute__((packed)); > > > > > > > > > > +/* Response header structure */ > > > > > +struct virtio_balloon_resp_hdr { > > > > > + __le64 cmd : 8; /* Distinguish different requests type */ > > > > > + __le64 flag: 8; /* Mark status for a specific request type */ > > > > > + __le64 id : 16; /* Distinguish requests of a specific type */ > > > > > + __le64 data_len: 32; /* Length of the following data, in bytes > > > > > +*/ > > > > > > > > This use of __le64 makes no sense. Just use u8/le16/le32 pls. > > > > > > > > > > Got it, will change in the next version. > > > > > > And could help take a look at other parts? as well as the QEMU part. > > > > > > Thanks! > > > Liang > > > > Yes but first I would like to understand how come no fields in this new > > structure come up if I search for them in the following patch. I don't see why > > It's not true, all of the field will be referenced in the following patches except > the 'reserved' filed. But none of these are used in the following patch 3. > > should I waste time on reviewing the implementation if the interface isn't > > reasonable. You don't have to waste it too - just send RFC patches with the > > header until we can agree on it. > > OK. I will post the header part separately. > > Thanks! > Liang > > > > -- > > MST > > > > --------------------------------------------------------------------- > > To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org > > For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org