From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH] niu: fix SMP race protecting rx_rings and tx_rings Date: Thu, 03 Feb 2011 15:22:14 -0800 (PST) Message-ID: <20110203.152214.59684545.davem@davemloft.net> References: <1296758717-18406-1-git-send-email-fleitner@redhat.com> <20110203.142145.183054407.davem@davemloft.net> <20110203231805.GA3710@redhat.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org To: fleitner@redhat.com Return-path: Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:43931 "EHLO sunset.davemloft.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752227Ab1BCXVi (ORCPT ); Thu, 3 Feb 2011 18:21:38 -0500 In-Reply-To: <20110203231805.GA3710@redhat.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Flavio Leitner Date: Thu, 3 Feb 2011 21:18:05 -0200 > Ok, I can write a new version using RCU if you like. Don't worry, I'll take care of it, I actually have the hardware to test on :-) > I've chose rwsem because I think those operations aren't > frequent. The RCU leaves an operation to run later during > a safe context, so I thought the cost doesn't worth it. One thing I'm worried about with your patch is that the statistics method can be called in basically any context, therefore a sleeping lock like the rw_semaphore is probably not usable. In fact I'm going to revert your patch for now because of this issue.