From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH v6 kernel 2/5] virtio-balloon: define new feature bit and head struct Date: Thu, 12 Jan 2017 21:43:15 +0200 Message-ID: <20170112185719-mutt-send-email-mst__1858.7576145821$1484250208$gmane$org@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> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <1482303148-22059-3-git-send-email-liang.z.li@intel.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Liang Li Cc: aarcange@redhat.com, virtio-dev@lists.oasis-open.org, kvm@vger.kernel.org, dave.hansen@intel.com, qemu-devel@nongnu.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-mm@kvack.org, amit.shah@redhat.com, pbonzini@redhat.com, dgilbert@redhat.com List-Id: virtualization@lists.linuxfoundation.org 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. > +}; > + > #endif /* _LINUX_VIRTIO_BALLOON_H */ > -- > 1.9.1