From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753807Ab2KPXWW (ORCPT ); Fri, 16 Nov 2012 18:22:22 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:46857 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753679Ab2KPXWV (ORCPT ); Fri, 16 Nov 2012 18:22:21 -0500 Date: Fri, 16 Nov 2012 15:22:19 -0800 From: Andrew Morton To: Oleg Nesterov Cc: Linus Torvalds , "Paul E. McKenney" , Mikulas Patocka , Peter Zijlstra , Ingo Molnar , Srikar Dronamraju , Ananth N Mavinakayanahalli , Anton Arapov , linux-kernel@vger.kernel.org Subject: Re: [PATCH -mm] percpu_rw_semaphore-reimplement-to-not-block-the-readers-unnecessari ly.fix Message-Id: <20121116152219.d4acc6d0.akpm@linux-foundation.org> In-Reply-To: <20121111182744.GA25282@redhat.com> References: <20121019192838.GM2518@linux.vnet.ibm.com> <20121030184800.GA16129@redhat.com> <20121031194135.GA504@redhat.com> <20121031194158.GB504@redhat.com> <20121102180606.GA13255@redhat.com> <20121108134805.GA23870@redhat.com> <20121108134849.GB23870@redhat.com> <20121108120700.42d438f2.akpm@linux-foundation.org> <20121111182744.GA25282@redhat.com> X-Mailer: Sylpheed 3.0.2 (GTK+ 2.20.1; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 11 Nov 2012 19:27:44 +0100 Oleg Nesterov wrote: > lib/percpu-rwsem.c | 35 +++++++++++++++++++++++++++++++++-- y'know, this looks like a great pile of useless bloat for single-CPU machines. Maybe add a CONFIG_SMP=n variant which simply calls the regular rwsem operations?