From mboxrd@z Thu Jan 1 00:00:00 1970 From: Evgeniy Polyakov Subject: Re: [PATCH RFC] v2 expedited "big hammer" RCU grace periods Date: Tue, 28 Apr 2009 00:56:02 +0400 Message-ID: <20090427205601.GA5716@ioremap.net> References: <20090426052340.GA24931@linux.vnet.ibm.com> <20090426112717.GE10391@elte.hu> <20090426191343.GC29238@Krystal> <20090426202255.GA5365@elte.hu> <20090426214451.GC6945@linux.vnet.ibm.com> <20090427032639.GA10087@elte.hu> <20090427132153.GI6945@linux.vnet.ibm.com> <20090427155424.GA27041@Krystal> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "Paul E. McKenney" , Ingo Molnar , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, netfilter-devel@vger.kernel.org, akpm@linux-foundation.org, torvalds@linux-foundation.org, davem@davemloft.net, dada1@cosmosbay.com, jeff.chua.linux@gmail.com, paulus@samba.org, laijs@cn.fujitsu.com, jengelh@medozas.de, r000n@r000n.net, benh@kernel.crashing.org To: Mathieu Desnoyers Return-path: Received: from cs-studio.ru ([195.178.208.66]:58603 "EHLO tservice.net.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756935AbZD0U4J (ORCPT ); Mon, 27 Apr 2009 16:56:09 -0400 Content-Disposition: inline In-Reply-To: <20090427155424.GA27041@Krystal> Sender: netfilter-devel-owner@vger.kernel.org List-ID: Hi. On Mon, Apr 27, 2009 at 11:54:24AM -0400, Mathieu Desnoyers (mathieu.desnoyers@polymtl.ca) wrote: > It might sound a bit simplistic, but... scheduling a high-priority > workqueue on every CPUs would give you the guarantees you seem to need > here. Or is the delay of letting the scheduler schedule a high-priority > task a delay you are trying to avoid ? I believe not the abstract (empty) task should be invoked, but a real task which does the work. Presumably if we want to schedule a way networking part to copy its counters, system should wake up the appropriate userspace thread blocked in a grace-period waking path, so effectively either RCU callback processing code or some registered thread should be awakened. Just a detail though. -- Evgeniy Polyakov