Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262671AbVDAIDt (ORCPT ); Fri, 1 Apr 2005 03:03:49 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262663AbVDAIBk (ORCPT ); Fri, 1 Apr 2005 03:01:40 -0500 Received: from fire.osdl.org ([65.172.181.4]:19383 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S262666AbVDAIAk (ORCPT ); Fri, 1 Apr 2005 03:00:40 -0500 Date: Thu, 31 Mar 2005 23:59:27 -0800 From: Andrew Morton To: johnpol@2ka.mipt.ru Cc: linux-kernel@vger.kernel.org, guillaume.thouvenin@bull.net, jlan@engr.sgi.com, efocht@hpce.nec.com, linuxram@us.ibm.com, gh@us.ibm.com, elsa-devel@lists.sourceforge.net, greg@kroah.com Subject: Re: [1/1] CBUS: new very fast (for insert operations) message bus based on kenel connector. Message-Id: <20050331235927.6d104665.akpm@osdl.org> In-Reply-To: <1112341514.9334.103.camel@uganda> References: <20050320112336.2b082e27@zanzibar.2ka.mipt.ru> <20050331162758.44aeaf44.akpm@osdl.org> <1112337814.9334.42.camel@uganda> <20050331232625.09057712.akpm@osdl.org> <1112341514.9334.103.camel@uganda> X-Mailer: Sylpheed version 0.9.7 (GTK+ 1.2.10; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1514 Lines: 40 Evgeniy Polyakov wrote: > > On Thu, 2005-03-31 at 23:26 -0800, Andrew Morton wrote: > > Evgeniy Polyakov wrote: > > > > > > > > +static int cbus_event_thread(void *data) > > > > > +{ > > > > > + int i, non_empty = 0, empty = 0; > > > > > + struct cbus_event_container *c; > > > > > + > > > > > + daemonize(cbus_name); > > > > > + allow_signal(SIGTERM); > > > > > + set_user_nice(current, 19); > > > > > > > > Please use the kthread api for managing this thread. > > > > > > > > Is a new kernel thread needed? > > > > > > Logic behind cbus is following: > > > 1. make insert operation return as soon as possible, > > > 2. deferring actual message delivering to the safe time > > > > > > That thread does second point. > > > > But does it need a new thread rather than using the existing keventd? > > Yes, it is much cleaner [especially from performance tuning point] > to use own kernel thread than pospone all work to the queued work. > Why? Unless keventd is off doing something else (rare), it should be exactly equivalent. And if keventd _is_ off doing something else then that will slow down this kernel thread too, of course. Plus keventd is thread-per-cpu and quite possibly would be faster. - 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/