From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 71557C433F5 for ; Tue, 5 Oct 2021 08:15:50 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id EAC516115B for ; Tue, 5 Oct 2021 08:15:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org EAC516115B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:57478 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mXfc3-0005X1-Cf for qemu-devel@archiver.kernel.org; Tue, 05 Oct 2021 04:15:49 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:46706) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mXfWG-0006DQ-2r for qemu-devel@nongnu.org; Tue, 05 Oct 2021 04:09:48 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:26551) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mXfWE-0005Io-B0 for qemu-devel@nongnu.org; Tue, 05 Oct 2021 04:09:47 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1633421385; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=t+6ORXs8UcjEYu6uoOB2fcLF3iJ1Dp0dFc99tBe7B0Y=; b=bqeun0wFucJ3mLzBQWgbeQOUdRYOO3p6Pf49WvZeb35H/caY0mvY4iYRYnvCHa8gpsbYx1 EiLUV0JuK4gaRmahoHpvxgBSLGvuBzpoG0OdxibCnJ5sMAHll6ya7Coojb/luIVtLz61dW sUg4/lbNuKuFAuavMNxhd3QQtQGnt6w= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-272-r4iyaI0zORKzz7kUrnF02g-1; Tue, 05 Oct 2021 04:09:43 -0400 X-MC-Unique: r4iyaI0zORKzz7kUrnF02g-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 3D923835DED; Tue, 5 Oct 2021 08:09:42 +0000 (UTC) Received: from localhost (unknown [10.39.194.5]) by smtp.corp.redhat.com (Postfix) with ESMTP id 89E605D9DE; Tue, 5 Oct 2021 08:09:36 +0000 (UTC) Date: Tue, 5 Oct 2021 09:09:35 +0100 From: Stefan Hajnoczi To: Vivek Goyal Subject: Re: [PATCH 06/13] vhost-user-fs: Use helpers to create/cleanup virtqueue Message-ID: References: <20210930153037.1194279-1-vgoyal@redhat.com> <20210930153037.1194279-7-vgoyal@redhat.com> MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=stefanha@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="+iqnBC8z7q5gu8r7" Content-Disposition: inline Received-SPF: pass client-ip=170.10.133.124; envelope-from=stefanha@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.066, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: miklos@szeredi.hu, qemu-devel@nongnu.org, iangelak@redhat.com, dgilbert@redhat.com, virtio-fs@redhat.com, jaggel@bu.edu Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" --+iqnBC8z7q5gu8r7 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Oct 04, 2021 at 03:58:09PM -0400, Vivek Goyal wrote: > On Mon, Oct 04, 2021 at 02:54:17PM +0100, Stefan Hajnoczi wrote: > > On Thu, Sep 30, 2021 at 11:30:30AM -0400, Vivek Goyal wrote: > > > Add helpers to create/cleanup virtuqueues and use those helpers. I wi= ll > >=20 > > s/virtuqueues/virtqueues/ > >=20 > > > need to reconfigure queues in later patches and using helpers will al= low > > > reusing the code. > > >=20 > > > Signed-off-by: Vivek Goyal > > > --- > > > hw/virtio/vhost-user-fs.c | 87 +++++++++++++++++++++++--------------= -- > > > 1 file changed, 52 insertions(+), 35 deletions(-) > > >=20 > > > diff --git a/hw/virtio/vhost-user-fs.c b/hw/virtio/vhost-user-fs.c > > > index c595957983..d1efbc5b18 100644 > > > --- a/hw/virtio/vhost-user-fs.c > > > +++ b/hw/virtio/vhost-user-fs.c > > > @@ -139,6 +139,55 @@ static void vuf_set_status(VirtIODevice *vdev, u= int8_t status) > > > } > > > } > > > =20 > > > +static void vuf_handle_output(VirtIODevice *vdev, VirtQueue *vq) > > > +{ > > > + /* > > > + * Not normally called; it's the daemon that handles the queue; > > > + * however virtio's cleanup path can call this. > > > + */ > > > +} > > > + > > > +static void vuf_create_vqs(VirtIODevice *vdev) > > > +{ > > > + VHostUserFS *fs =3D VHOST_USER_FS(vdev); > > > + unsigned int i; > > > + > > > + /* Hiprio queue */ > > > + fs->hiprio_vq =3D virtio_add_queue(vdev, fs->conf.queue_size, > > > + vuf_handle_output); > > > + > > > + /* Request queues */ > > > + fs->req_vqs =3D g_new(VirtQueue *, fs->conf.num_request_queues); > > > + for (i =3D 0; i < fs->conf.num_request_queues; i++) { > > > + fs->req_vqs[i] =3D virtio_add_queue(vdev, fs->conf.queue_siz= e, > > > + vuf_handle_output); > > > + } > > > + > > > + /* 1 high prio queue, plus the number configured */ > > > + fs->vhost_dev.nvqs =3D 1 + fs->conf.num_request_queues; > > > + fs->vhost_dev.vqs =3D g_new0(struct vhost_virtqueue, fs->vhost_d= ev.nvqs); > >=20 > > These two lines prepare for vhost_dev_init(), so moving them here is > > debatable. If a caller is going to use this function again in the futur= e > > then they need to be sure to also call vhost_dev_init(). For now it > > looks safe, so I guess it's okay. >=20 > Hmm..., I do call this function later from vuf_set_features() and > reconfigure the queues. I see that I don't call vhost_dev_init() > in that path. I am not even sure if I should be calling > vhost_dev_init() from inside vuf_set_features(). >=20 > So core reuirement is that at the time of first creating device > I have no idea if driver supports notification queue or not. So > I do create device with notification queue. But later if driver > (and possibly vhost device) does not support notifiation queue, > then we need to reconfigure queues. What's the correct way to > do that? Ah, I see. The simplest approach is to always allocate the maximum number of virtqueues. QEMU's vhost-user-fs device shouldn't need to worry about which virtqueues are actually in use. Let virtiofsd (the vhost-user backend) worry about that. I posted ideas about how to do that in a reply to another patch in this series. I can't guarantee it will work, but I think it's worth exploring. Stefan --+iqnBC8z7q5gu8r7 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEhpWov9P5fNqsNXdanKSrs4Grc8gFAmFcCD8ACgkQnKSrs4Gr c8jdjgf/e1SGpQd5MmZoaTevqKLpWjV3OK81VQtwN4FSZSjYCxyj5PVrp7c31bIR da/751eNaluxZR3EcOH+0J8FmPbkWuLTlNeCvBl+h1jkbg6h6jztDs1tXIIiUTBW ZApCIgBr4LdfsvBZ/3m2072V9zcUQGnhERVrhvJ7Nx5/TbLwP/LpxLHLYcD0VGfJ KtvYcTouN9VlTvgeT2zDhcqlsuy74t/4Xpu/0dmIgozNj1RHYRg04ew7tIgFLUOz kz3RYYxvr0h/A1SxokRP2W565kgU/IYLZ0m+Fgzp2tmeR9+iCk8UJ3rG+h2lqPoK YWLtzEC4sLDbn48B3nzkzuYo9vpU5w== =DUE7 -----END PGP SIGNATURE----- --+iqnBC8z7q5gu8r7-- From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 5 Oct 2021 09:09:35 +0100 From: Stefan Hajnoczi Message-ID: References: <20210930153037.1194279-1-vgoyal@redhat.com> <20210930153037.1194279-7-vgoyal@redhat.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="+iqnBC8z7q5gu8r7" Content-Disposition: inline In-Reply-To: Subject: Re: [Virtio-fs] [PATCH 06/13] vhost-user-fs: Use helpers to create/cleanup virtqueue List-Id: Development discussions about virtio-fs List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Vivek Goyal Cc: miklos@szeredi.hu, qemu-devel@nongnu.org, virtio-fs@redhat.com --+iqnBC8z7q5gu8r7 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Oct 04, 2021 at 03:58:09PM -0400, Vivek Goyal wrote: > On Mon, Oct 04, 2021 at 02:54:17PM +0100, Stefan Hajnoczi wrote: > > On Thu, Sep 30, 2021 at 11:30:30AM -0400, Vivek Goyal wrote: > > > Add helpers to create/cleanup virtuqueues and use those helpers. I wi= ll > >=20 > > s/virtuqueues/virtqueues/ > >=20 > > > need to reconfigure queues in later patches and using helpers will al= low > > > reusing the code. > > >=20 > > > Signed-off-by: Vivek Goyal > > > --- > > > hw/virtio/vhost-user-fs.c | 87 +++++++++++++++++++++++--------------= -- > > > 1 file changed, 52 insertions(+), 35 deletions(-) > > >=20 > > > diff --git a/hw/virtio/vhost-user-fs.c b/hw/virtio/vhost-user-fs.c > > > index c595957983..d1efbc5b18 100644 > > > --- a/hw/virtio/vhost-user-fs.c > > > +++ b/hw/virtio/vhost-user-fs.c > > > @@ -139,6 +139,55 @@ static void vuf_set_status(VirtIODevice *vdev, u= int8_t status) > > > } > > > } > > > =20 > > > +static void vuf_handle_output(VirtIODevice *vdev, VirtQueue *vq) > > > +{ > > > + /* > > > + * Not normally called; it's the daemon that handles the queue; > > > + * however virtio's cleanup path can call this. > > > + */ > > > +} > > > + > > > +static void vuf_create_vqs(VirtIODevice *vdev) > > > +{ > > > + VHostUserFS *fs =3D VHOST_USER_FS(vdev); > > > + unsigned int i; > > > + > > > + /* Hiprio queue */ > > > + fs->hiprio_vq =3D virtio_add_queue(vdev, fs->conf.queue_size, > > > + vuf_handle_output); > > > + > > > + /* Request queues */ > > > + fs->req_vqs =3D g_new(VirtQueue *, fs->conf.num_request_queues); > > > + for (i =3D 0; i < fs->conf.num_request_queues; i++) { > > > + fs->req_vqs[i] =3D virtio_add_queue(vdev, fs->conf.queue_siz= e, > > > + vuf_handle_output); > > > + } > > > + > > > + /* 1 high prio queue, plus the number configured */ > > > + fs->vhost_dev.nvqs =3D 1 + fs->conf.num_request_queues; > > > + fs->vhost_dev.vqs =3D g_new0(struct vhost_virtqueue, fs->vhost_d= ev.nvqs); > >=20 > > These two lines prepare for vhost_dev_init(), so moving them here is > > debatable. If a caller is going to use this function again in the future > > then they need to be sure to also call vhost_dev_init(). For now it > > looks safe, so I guess it's okay. >=20 > Hmm..., I do call this function later from vuf_set_features() and > reconfigure the queues. I see that I don't call vhost_dev_init() > in that path. I am not even sure if I should be calling > vhost_dev_init() from inside vuf_set_features(). >=20 > So core reuirement is that at the time of first creating device > I have no idea if driver supports notification queue or not. So > I do create device with notification queue. But later if driver > (and possibly vhost device) does not support notifiation queue, > then we need to reconfigure queues. What's the correct way to > do that? Ah, I see. The simplest approach is to always allocate the maximum number of virtqueues. QEMU's vhost-user-fs device shouldn't need to worry about which virtqueues are actually in use. Let virtiofsd (the vhost-user backend) worry about that. I posted ideas about how to do that in a reply to another patch in this series. I can't guarantee it will work, but I think it's worth exploring. Stefan --+iqnBC8z7q5gu8r7 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEhpWov9P5fNqsNXdanKSrs4Grc8gFAmFcCD8ACgkQnKSrs4Gr c8jdjgf/e1SGpQd5MmZoaTevqKLpWjV3OK81VQtwN4FSZSjYCxyj5PVrp7c31bIR da/751eNaluxZR3EcOH+0J8FmPbkWuLTlNeCvBl+h1jkbg6h6jztDs1tXIIiUTBW ZApCIgBr4LdfsvBZ/3m2072V9zcUQGnhERVrhvJ7Nx5/TbLwP/LpxLHLYcD0VGfJ KtvYcTouN9VlTvgeT2zDhcqlsuy74t/4Xpu/0dmIgozNj1RHYRg04ew7tIgFLUOz kz3RYYxvr0h/A1SxokRP2W565kgU/IYLZ0m+Fgzp2tmeR9+iCk8UJ3rG+h2lqPoK YWLtzEC4sLDbn48B3nzkzuYo9vpU5w== =DUE7 -----END PGP SIGNATURE----- --+iqnBC8z7q5gu8r7--