Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751483AbWAFNAI (ORCPT ); Fri, 6 Jan 2006 08:00:08 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751485AbWAFNAI (ORCPT ); Fri, 6 Jan 2006 08:00:08 -0500 Received: from mx2.suse.de ([195.135.220.15]:57029 "EHLO mx2.suse.de") by vger.kernel.org with ESMTP id S1751483AbWAFNAG (ORCPT ); Fri, 6 Jan 2006 08:00:06 -0500 From: Andi Kleen To: Eric Dumazet Subject: Re: [PATCH, RFC] RCU : OOM avoidance and lower latency Date: Fri, 6 Jan 2006 13:58:41 +0100 User-Agent: KMail/1.8 Cc: Linus Torvalds , linux-kernel@vger.kernel.org, "David S. Miller" , Dipankar Sarma , "Paul E. McKenney" , Manfred Spraul , netdev@vger.kernel.org References: <20060105235845.967478000@sorel.sous-sol.org> <43BE43B6.3010105@cosmosbay.com> In-Reply-To: <43BE43B6.3010105@cosmosbay.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200601061358.42344.ak@suse.de> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 792 Lines: 20 On Friday 06 January 2006 11:17, Eric Dumazet wrote: > > I assume that if a CPU queued 10.000 items in its RCU queue, then the > oldest entry cannot still be in use by another CPU. This might sounds as a > violation of RCU rules, (I'm not an RCU expert) but seems quite reasonable. I don't think it's a good assumption. Another CPU might be stuck in a long running interrupt, and still have a reference in the code running below the interrupt handler. And in general letting correctness depend on magic numbers like this is very nasty. -Andi - 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/