From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kay Sievers Date: Tue, 26 May 2009 15:31:48 +0000 Subject: Re: [PATCH 1/2] udevd: respect the value of TIMEOUT in uevents Message-Id: List-Id: References: <4A1BBBE6.4040202@tuffmail.co.uk> In-Reply-To: <4A1BBBE6.4040202@tuffmail.co.uk> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-hotplug@vger.kernel.org On Tue, May 26, 2009 at 12:19, Alan Jenkins wrote: > Don't apply patch 2 then :-). No worry, we can not be that fast here. :) We need to get numbers first. Threads don't come for free, they make udev much less reliable and harder to debug, compared to the current model. When all events share the same address space, and the memory for the events gets reused for forever, a simple bug will likely bring down the entire service, unlike today where an event process may crash, but the event management daemon will survive. Actually, I don't remember that the main udev ever crashed, and that will definitely change with the threads. :) I'm not against a threaded udevd, but we should have a good reason to do it that way. We also need to get numbers on bigger boxes. Udev runs on boxes with many thousands of events at bootup. we've seen boxes with 20.000+ disks, where every disk has ~10 devices in sysfs. Some of the SUSE customers requested to be able to run 4000+ events in parallel, to bring the bootup time on such boxes down to a reasonable time. That all works fine with today's udev and we need to be really careful here. Thanks, Kay