From owner-freebsd-current@FreeBSD.ORG Tue Aug 28 17:26:27 2012 Return-Path: <owner-freebsd-current@FreeBSD.ORG> Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 15026106564A; Tue, 28 Aug 2012 17:26:27 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from mail.zoral.com.ua (mx0.zoral.com.ua [91.193.166.200]) by mx1.freebsd.org (Postfix) with ESMTP id 9FFD38FC1D; Tue, 28 Aug 2012 17:26:26 +0000 (UTC) Received: from skuns.kiev.zoral.com.ua (localhost [127.0.0.1]) by mail.zoral.com.ua (8.14.2/8.14.2) with ESMTP id q7SHQIl2033178; Tue, 28 Aug 2012 20:26:18 +0300 (EEST) (envelope-from kostikbel@gmail.com) Received: from deviant.kiev.zoral.com.ua (kostik@localhost [127.0.0.1]) by deviant.kiev.zoral.com.ua (8.14.5/8.14.5) with ESMTP id q7SHQ66U066624; Tue, 28 Aug 2012 20:26:06 +0300 (EEST) (envelope-from kostikbel@gmail.com) Received: (from kostik@localhost) by deviant.kiev.zoral.com.ua (8.14.5/8.14.5/Submit) id q7SHQ6xk066623; Tue, 28 Aug 2012 20:26:06 +0300 (EEST) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: deviant.kiev.zoral.com.ua: kostik set sender to kostikbel@gmail.com using -f Date: Tue, 28 Aug 2012 20:26:06 +0300 From: Konstantin Belousov <kostikbel@gmail.com> To: John Baldwin <jhb@freebsd.org> Message-ID: <20120828172606.GR33100@deviant.kiev.zoral.com.ua> References: <20120827073403.GA49223@onelab2.iet.unipi.it> <201208271227.54785.jhb@freebsd.org> <20120828155025.GA66068@onelab2.iet.unipi.it> <201208281240.29612.jhb@freebsd.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="LVYvhoM65K2KO2My" Content-Disposition: inline In-Reply-To: <201208281240.29612.jhb@freebsd.org> User-Agent: Mutt/1.4.2.3i X-Virus-Scanned: clamav-milter 0.95.2 at skuns.kiev.zoral.com.ua X-Virus-Status: Clean X-Spam-Status: No, score=-4.0 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00 autolearn=ham version=3.2.5 X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on skuns.kiev.zoral.com.ua Cc: freebsd-current@freebsd.org, Luigi Rizzo <rizzo@iet.unipi.it>, current@freebsd.org, Andriy Gapon <avg@freebsd.org> Subject: Re: per file descriptor device callbacks ? X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current <freebsd-current.freebsd.org> List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-current>, <mailto:freebsd-current-request@freebsd.org?subject=unsubscribe> List-Archive: <http://lists.freebsd.org/pipermail/freebsd-current> List-Post: <mailto:freebsd-current@freebsd.org> List-Help: <mailto:freebsd-current-request@freebsd.org?subject=help> List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-current>, <mailto:freebsd-current-request@freebsd.org?subject=subscribe> X-List-Received-Date: Tue, 28 Aug 2012 17:26:27 -0000 --LVYvhoM65K2KO2My Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Aug 28, 2012 at 12:40:29PM -0400, John Baldwin wrote: > On Tuesday, August 28, 2012 11:50:25 am Luigi Rizzo wrote: > > On Mon, Aug 27, 2012 at 12:27:54PM -0400, John Baldwin wrote: > > > On Monday, August 27, 2012 3:55:47 am Andriy Gapon wrote: > > > > on 27/08/2012 10:34 Luigi Rizzo said the following: > > > > > This requires to track calls to open/ioctl/poll/mmap/close. > > > > > The difficulty i have is with mmap() and close(), because FreeBSD > > > > > seems to handle these calls per-cdev rather than per-file-descrip= tor > > > > > (for instance, no 'struct file' argument is available in mmap(), = and > > > > > the d_close method is only called on the last close() on the devi= ce). > > > >=20 > > > > devfs_set_cdevpriv(9), etc > > >=20 > > > mmap() is still problematic, but if you have the freedom to create yo= ur > > > own VM objects, then d_mmap_single() can let you handle that fairly > > > easily. > >=20 > > Would dev_clone(9) be a better way to do what i need ? > >=20 > > This way the struct cdev would be unique per file descriptor, > > could be used as a key on the page fault callbacks > > (i still do not have callbacks on dev_pager_ctor/dtor though). >=20 > dev_clone() is rather gross and a lot harder to use than > devfs_set_cdevpriv(). If you are fine with the inherent problems > of the device pager (you can't ever make mappings go away), you can > just assign each client a unique offset into your shared object's > memory space. However, if you are exporting shared memory buffers, > then a better model might be to let your clients use > shm_open(SHM_ANON) to create buffers, then pass them into your driver > via an ioctl() and use shm_map() to map them into the kernel. Well, there is a new OBJT_MGTDEVICE pager, which together with d_mmap_single() allows to have even per-mapping data. i915kms uses it. You do not need cdevpriv for the per-mapping data. Also, MGTDEVICE does track the mappings of the pages, so you can clean up on device destruction. Normal callbacks of the device pager allows to execute ctr/dtr methods at the time of mapping creation and tear down. --LVYvhoM65K2KO2My Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (FreeBSD) iEYEARECAAYFAlA8/y4ACgkQC3+MBN1Mb4j+IQCcC4kuXuh0BiqrbWZ3AwiqZ04z JXMAoPHNNYuNMS9AfW2Q7D+UdaTQk5vP =WWkn -----END PGP SIGNATURE----- --LVYvhoM65K2KO2My--