Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754237AbWKGSTK (ORCPT ); Tue, 7 Nov 2006 13:19:10 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965673AbWKGSTJ (ORCPT ); Tue, 7 Nov 2006 13:19:09 -0500 Received: from omx2-ext.sgi.com ([192.48.171.19]:63450 "EHLO omx2.sgi.com") by vger.kernel.org with ESMTP id S1754224AbWKGSTG (ORCPT ); Tue, 7 Nov 2006 13:19:06 -0500 Date: Tue, 7 Nov 2006 10:18:44 -0800 (PST) From: Christoph Lameter To: "Siddha, Suresh B" cc: Ingo Molnar , akpm@osdl.org, mm-commits@vger.kernel.org, nickpiggin@yahoo.com.au, linux-kernel@vger.kernel.org Subject: Re: + sched-use-tasklet-to-call-balancing.patch added to -mm tree In-Reply-To: <20061107095049.B3262@unix-os.sc.intel.com> Message-ID: References: <200611032205.kA3M5wmJ003178@shell0.pdx.osdl.net> <20061107073248.GB5148@elte.hu> <20061107093112.A3262@unix-os.sc.intel.com> <20061107095049.B3262@unix-os.sc.intel.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1264 Lines: 34 On Tue, 7 Nov 2006, Siddha, Suresh B wrote: > tasklet_schedule doesn't schedule if there is already one scheduled. Right. /* Tasklets --- multithreaded analogue of BHs. Main feature differing them of generic softirqs: tasklet is running only on one CPU simultaneously. Main feature differing them of BHs: different tasklets may be run simultaneously on different CPUs. Properties: * If tasklet_schedule() is called, then tasklet is guaranteed to be executed on some cpu at least once after this. ^^^^ Crap. Not equivalent. Must be guaranteed to run on the same cpu. * If the tasklet is already scheduled, but its excecution is still not started, it will be executed only once. * If this tasklet is already running on another CPU (or schedule is called from tasklet itself), it is rescheduled for later. * Tasklet is strictly serialized wrt itself, but not wrt another tasklets. If client needs some intertask synchronization, he makes it with spinlocks. */ - 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/