From owner-freebsd-current@FreeBSD.ORG Mon Feb 2 09:30:42 2015 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 84AEB346 for ; Mon, 2 Feb 2015 09:30:42 +0000 (UTC) Received: from kib.kiev.ua (kib.kiev.ua [IPv6:2001:470:d5e7:1::1]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id EAF35810 for ; Mon, 2 Feb 2015 09:30:41 +0000 (UTC) Received: from tom.home (kostik@localhost [127.0.0.1]) by kib.kiev.ua (8.14.9/8.14.9) with ESMTP id t129URem037378 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Mon, 2 Feb 2015 11:30:27 +0200 (EET) (envelope-from kostikbel@gmail.com) DKIM-Filter: OpenDKIM Filter v2.9.2 kib.kiev.ua t129URem037378 Received: (from kostik@localhost) by tom.home (8.14.9/8.14.9/Submit) id t129URPV037377; Mon, 2 Feb 2015 11:30:27 +0200 (EET) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: tom.home: kostik set sender to kostikbel@gmail.com using -f Date: Mon, 2 Feb 2015 11:30:27 +0200 From: Konstantin Belousov To: Eric Badger Subject: Re: Filepaths in VM map for tmpfs files Message-ID: <20150202093027.GL42409@kib.kiev.ua> References: <54CCEFAB.9040406@badgerio.us> <20150131153621.GH42409@kib.kiev.ua> <54CEE325.4040903@badgerio.us> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <54CEE325.4040903@badgerio.us> User-Agent: Mutt/1.5.23 (2014-03-12) X-Spam-Status: No, score=-2.0 required=5.0 tests=ALL_TRUSTED,BAYES_00, DKIM_ADSP_CUSTOM_MED,FREEMAIL_FROM,NML_ADSP_CUSTOM_MED autolearn=no autolearn_force=no version=3.4.0 X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on tom.home Cc: freebsd-current@freebsd.org X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 02 Feb 2015 09:30:42 -0000 On Sun, Feb 01, 2015 at 08:38:29PM -0600, Eric Badger wrote: > > On 01/31/2015 09:36 AM, Konstantin Belousov wrote: > > First, shouldn't the kve_type changed to KVME_TYPE_VNODE as well ? > My thinking is no, because KVME_TYPE_SWAP is in fact the correct type; > I'd opine that it is better to be transparent than make it look like > there is an OBJT_VNODE object there. It may be that some programs would > be confused by VNODE info returned on a SWAP type mapping, though I know > that dtrace handles it OK. kve_vn_* and kve_path fields are defined only for KVME_TYPE_VNODE kve_type. So this is in fact a bug in whatever used the API to access kve_path for KVE_TYPE_SWAP. > > > Second, note that it is possible that the vnode is recycled, so > > OBJ_TMPFS flag is cleared for tmpfs swap object. The OBJ_TMPFS_NODE > > flag is still set then. I am not sure what to do in this case, > > should the type changed to KVME_TYPE_VNODE still, but kve_vn_* > > fields left invalid ? > I think if we changed to KVME_TYPE_VNODE in some cases, it should be > done in all cases, even if the vnode has been recycled (but leave vp == > NULL in that case). Though if it is left as KVME_TYPE_SWAP, then that > concern goes away on its own. Concern is not vp == NULL, but the fact that kve_vn* cannot be filled, there is simply no (easy) way to fetch this information.