From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sat, 11 May 2002 15:48:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sat, 11 May 2002 15:48:26 -0400 Received: from parcelfarce.linux.theplanet.co.uk ([195.92.249.252]:40711 "EHLO www.linux.org.uk") by vger.kernel.org with ESMTP id ; Sat, 11 May 2002 15:48:25 -0400 Date: Sat, 11 May 2002 20:48:20 +0100 From: Matthew Wilcox To: Andrew Morton Cc: Dave Hansen , matthew@wil.cx, linux-kernel@vger.kernel.org Subject: Re: fs/locks.c BKL removal Message-ID: <20020511204820.N32414@parcelfarce.linux.theplanet.co.uk> In-Reply-To: <3CDC4037.8040104@us.ibm.com> <3CDC45EF.9000506@us.ibm.com> <3CDC5509.DCAF336A@zip.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 10, 2002 at 04:17:29PM -0700, Andrew Morton wrote: > It was I who put the BKL back into locks.c, much to > Matthew's disgust... The disgust was targetted more at removing the abstraction of locking scheme which I'd put in and having explicit lock_kernel() / unlock_kernel() calls. I'd used (iirc) acquire_lock() / release_lock() macros which could have just been redefined. > The problem was that replacing the BKL with a semaphore > seriously damaged Apache thoughput on 8-way. Apache > was using flock()-based synchronisation and replacing > a spin with a schedule just killed it. Which says that our semaphores suck, because they don't try to spin for a bit before scheduling. Of course, your change back was the right thing to do in the 2.3.late timeframe. -- Revolutions do not require corporate support.