From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f198.google.com (mail-pf0-f198.google.com [209.85.192.198]) by kanga.kvack.org (Postfix) with ESMTP id 646136B0069 for ; Wed, 18 Jan 2017 20:31:02 -0500 (EST) Received: by mail-pf0-f198.google.com with SMTP id 80so39216822pfy.2 for ; Wed, 18 Jan 2017 17:31:02 -0800 (PST) Received: from mga05.intel.com (mga05.intel.com. [192.55.52.43]) by mx.google.com with ESMTPS id 3si1895258plo.4.2017.01.18.17.31.01 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 18 Jan 2017 17:31:01 -0800 (PST) From: "Li, Liang Z" Subject: RE: [virtio-dev] Re: [PATCH v6 kernel 2/5] virtio-balloon: define new feature bit and head struct Date: Thu, 19 Jan 2017 01:30:57 +0000 Message-ID: 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> <20170118173025-mutt-send-email-mst@kernel.org> In-Reply-To: <20170118173025-mutt-send-email-mst@kernel.org> Content-Language: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: owner-linux-mm@kvack.org List-ID: To: "Michael S. Tsirkin" 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" > > > > > > 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. >=20 > But none of these are used in the following patch 3. Yes. Only 'data_len' is used in patch 3, and for expansibility maybe at lea= st 'cmd' is needed to. I should set it in patch 3 to some default value eve= n it's not currently useful. 'flag' and 'id' are for patch 4. I just want to = reuse the 'struct virtio_balloon_resp_hdr' and make the code simpler. Thanks! Liang -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org