From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sc8-sf-mx1-b.sourceforge.net ([10.3.1.91] helo=mail.sourceforge.net) by sc8-sf-list1.sourceforge.net with esmtp (Exim 4.30) id 1FZTQj-0006Pz-Rs for user-mode-linux-devel@lists.sourceforge.net; Fri, 28 Apr 2006 06:54:45 -0700 Received: from smtp005.mail.ukl.yahoo.com ([217.12.11.36]) by mail.sourceforge.net with smtp (Exim 4.44) id 1FZTQi-0007I1-Hc for user-mode-linux-devel@lists.sourceforge.net; Fri, 28 Apr 2006 06:54:46 -0700 From: Blaisorblade Subject: Re: [uml-devel] Re: [RFC] PATCH 0/4 - Time virtualization References: <200604131719.k3DHJcZG004674@ccure.user-mode-linux.org> <200604281333.41358.blaisorblade@yahoo.it> <20060428114823.GA3641@ccure.user-mode-linux.org> In-Reply-To: <20060428114823.GA3641@ccure.user-mode-linux.org> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200604281554.32665.blaisorblade@yahoo.it> Sender: user-mode-linux-devel-admin@lists.sourceforge.net Errors-To: user-mode-linux-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Id: The user-mode Linux development list List-Post: List-Help: List-Subscribe: , List-Archive: Date: Fri, 28 Apr 2006 15:54:31 +0200 To: Jeff Dike Cc: user-mode-linux-devel@lists.sourceforge.net, "Eric W. Biederman" , linux-kernel@vger.kernel.org On Friday 28 April 2006 13:48, Jeff Dike wrote: > On Fri, Apr 28, 2006 at 01:33:40PM +0200, Blaisorblade wrote: > > > So, maybe it belongs in clone as a "backwards" flag similar to > > > CLONE_NEWNS. > > I must note that currently every (?) flag allowed for unshare is also > > allowed for clone, so you need to do that anyway. > Currently. We are running out of CLONE_ bits - in mainline, there are > three left, and two of them are likely to be used by CLONE_TIME and > CLONE_UTSNAME (or whatever that turns out to be called). > And why should there be any overlap between clone flags and unshare > flags? Isn't > clone(CLONE_TIME); > the same as > clone(); > unshare(CLONE_TIME); > ? Now that unshare() exists, you're right, the current situation is just due to unshare() being an afterthought; the second form (clone() + unshare()) is actually more similar to the classical fork() API conceptually (i.e. you don't need a call with thousands of parameters to create a process, you can specify everything later). So we get back to Eric's objection (which I haven't understood but that's my problem). Additionally, if this flag ever goes into clone, it mustn't be named CLONE_TIME, but CLONE_NEWTIME (or CLONE_NEWUTS). And given CLONE_NEWNS, it's IMHO ok to have unshare(CLONE_NEWTIME) to mean "unshare time namespace", even if it's incoherent with unshare(CLONE_FS) - the incoherency already exists with CLONE_NEWNS. -- Inform me of my mistakes, so I can keep imitating Homer Simpson's "Doh!". Paolo Giarrusso, aka Blaisorblade (Skype ID "PaoloGiarrusso", ICQ 215621894) http://www.user-mode-linux.org/~blaisorblade Chiacchiera con i tuoi amici in tempo reale! http://it.yahoo.com/mail_it/foot/*http://it.messenger.yahoo.com ------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel