From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261826AbVCMJh1 (ORCPT ); Sun, 13 Mar 2005 04:37:27 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263461AbVCMJh1 (ORCPT ); Sun, 13 Mar 2005 04:37:27 -0500 Received: from bay-bridge.veritas.com ([143.127.3.10]:11056 "EHLO MTVMIME03.enterprise.veritas.com") by vger.kernel.org with ESMTP id S261826AbVCMJhW (ORCPT ); Sun, 13 Mar 2005 04:37:22 -0500 Date: Sun, 13 Mar 2005 09:35:59 +0000 (GMT) From: Hugh Dickins X-X-Sender: hugh@goblin.wat.veritas.com To: Arjan van de Ven cc: Andrew Morton , mingo@elte.hu, nickpiggin@yahoo.com.au, linux-kernel@vger.kernel.org Subject: Re: [PATCH] break_lock forever broken In-Reply-To: <1110702194.6278.31.camel@laptopd505.fenrus.org> Message-ID: References: <20050311203427.052f2b1b.akpm@osdl.org> <1110702194.6278.31.camel@laptopd505.fenrus.org> 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 On Sun, 13 Mar 2005, Arjan van de Ven wrote: > > \ > > + if ((lock)->break_lock) \ > > + (lock)->break_lock = 0; \ > > } \ > if it really worth an conditional there? the cacheline of the lock is > made dirty anyway on unlock, so writing an extra 0 is like almost free > (maybe half a cycle) while a conditional jump can be 100+.... I wondered the same, I don't know and would defer to those who do: really I was just following the style of where break_lock is set above, which follows soon (unless preempted) after a _raw_whatever_trylock. Hugh