Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161109AbWHJO07 (ORCPT ); Thu, 10 Aug 2006 10:26:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751263AbWHJO07 (ORCPT ); Thu, 10 Aug 2006 10:26:59 -0400 Received: from sd291.sivit.org ([194.146.225.122]:57352 "EHLO sd291.sivit.org") by vger.kernel.org with ESMTP id S1751186AbWHJO06 (ORCPT ); Thu, 10 Aug 2006 10:26:58 -0400 Subject: Re: [PATCH] memory ordering in __kfifo primitives From: Stelian Pop To: paulmck@us.ibm.com Cc: Mike Christie , linux-kernel@vger.kernel.org, akpm@osdl.org, paulus@au1.ibm.com, anton@au1.ibm.com, open-iscsi@googlegroups.com, pradeep@us.ibm.com, mashirle@us.ibm.com In-Reply-To: <20060810134135.GB1298@us.ibm.com> References: <20060810001823.GA3026@us.ibm.com> <20060810003310.GA3071@us.ibm.com> <44DAC892.7000100@cs.wisc.edu> <20060810134135.GB1298@us.ibm.com> Content-Type: text/plain; charset=ISO-8859-15 Date: Thu, 10 Aug 2006 16:26:53 +0200 Message-Id: <1155220013.1108.4.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.6.1 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1057 Lines: 27 Le jeudi 10 ao?t 2006 ? 06:41 -0700, Paul E. McKenney a ?crit : > I am happy to go either way -- the patch with the memory barriers > (which does have the side-effect of slowing down kfifo_get() and > kfifo_put(), by the way), or a patch removing the comments saying > that it is OK to invoke __kfifo_get() and __kfifo_put() without > locking. > > Any other thoughts on which is better? (1) the memory barriers or > (2) requiring the caller hold appropriate locks across calls to > __kfifo_get() and __kfifo_put()? If someone wants to use explicit locking, he/she can go with kfifo_get() instead of the __ version. I'd rather keep the __kfifo_get() and __kfifo_put() functions lockless, so I say go for (1) even if there is a tiny price to pay for corectness. Stelian. -- Stelian Pop - 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/