From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261876AbTDKWXd (for ); Fri, 11 Apr 2003 18:23:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261884AbTDKWXc (for ); Fri, 11 Apr 2003 18:23:32 -0400 Received: from fw-az.mvista.com ([65.200.49.158]:55545 "EHLO zipcode.az.mvista.com") by vger.kernel.org with ESMTP id S261876AbTDKWXb (for ); Fri, 11 Apr 2003 18:23:31 -0400 Message-ID: <3E974348.7080104@mvista.com> Date: Fri, 11 Apr 2003 15:35:52 -0700 From: Steven Dake User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.3) Gecko/20030312 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Arnd Bergmann CC: linux-kernel@vger.kernel.org Subject: Re: [ANNOUNCE] udev 0.1 release References: <20030411173018$2695@gated-at.bofh.it> <20030411175011$3d7e@gated-at.bofh.it> <20030411182022$7f7a@gated-at.bofh.it> <20030411184016$1180@gated-at.bofh.it> <20030411204006$0496@gated-at.bofh.it> <20030411205018$7440@gated-at.bofh.it> <200304112111.h3BLBWgu025834@post.webmailer.de> In-Reply-To: <200304112111.h3BLBWgu025834@post.webmailer.de> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Arnd Bergmann wrote: >Greg KH wrote: > > > >>On Fri, Apr 11, 2003 at 01:29:57PM -0700, Steven Dake wrote: >> >> >>>It gets even worse, because performance of hotswap events on disk adds >>>is critical and spawning processes is incredibly slow compared to the >>>performance required by some telecom applications... >>> >>> >>It's critical that we quick name this disk within X milliseconds after >>it has been added to the system? What spec declares this? >> >> > >While the problem might not really be the per-device latency, what should >be handled correctly is the following scenario: > >- Someone accidentally removes the cable that connects a few hundred > (mounted) disks >- The cable is replaced, but - oops - to the wrong socket >- The person notices the error and now places the cable into the right > socket. > >At this time we have four concurrent hotplug events for every single >disks that we want to be finished in order and we want every disk >to end up with its original minor number in the end. If this is not >possible, the system still needs to be in a sensible state after this. > > Yes, and in the rest of my email, I stated this would be solved by replacing /sbin/hotplug with a mechanism to communicate events to a user space daemon which would process requests in order as submitted by the kernel. (All except the same minor/major, which may or may not happen). If the kernel is evil and doesn't submit events in order, thats another problem to solve, but it should for disk events, atleast. > Arnd <>< >- >To unsubscribe from this list: send the line "unsubscribe linux-kernel" in >the body of a message to majordomo@vger.kernel.org >More majordomo info at http://vger.kernel.org/majordomo-info.html >Please read the FAQ at http://www.tux.org/lkml/ > > > > >