From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261665AbTDKViB (for ); Fri, 11 Apr 2003 17:38:01 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261757AbTDKViB (for ); Fri, 11 Apr 2003 17:38:01 -0400 Received: from [12.47.58.73] ([12.47.58.73]:40170 "EHLO pao-ex01.pao.digeo.com") by vger.kernel.org with ESMTP id S261665AbTDKViA (for ); Fri, 11 Apr 2003 17:38:00 -0400 Date: Fri, 11 Apr 2003 14:49:42 -0700 From: Andrew Morton To: Hanna Linder Cc: linux-kernel@vger.kernel.org Subject: Re: [Lockmeter 2.5] BKL with 51ms hold time, prove me wrong Message-Id: <20030411144942.4934832d.akpm@digeo.com> In-Reply-To: <34680000.1050084914@w-hlinder> References: <46950000.1050023701@w-hlinder> <20030410185006.5fd88c30.akpm@digeo.com> <34680000.1050084914@w-hlinder> X-Mailer: Sylpheed version 0.8.10 (GTK+ 1.2.10; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 11 Apr 2003 21:49:39.0227 (UTC) FILETIME=[4058BEB0:01C30074] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hanna Linder wrote: > > > Sure enough. I ported lockmeter to 2.5.67-mm1 and ran the same rmap-test > and lo and behold all the ext3 issues went away. However, the one remaining > long hold time moved to the top (unmap_vmas): Ah, but the unmap_vmas lock was not kernel_flag, was it? It'll be page_table_lock. That's OK I think. The only time this is likely to bite anyone is if you have a threaded application in which one thread it doing a massive munmap() while another one is handling a pagefault, running mmap(), etc. And given that _establishing_ that large mapping in the first place takes tons of CPU, the relative loss from the long hold time is small. Famous last words. > > Here is the port of lockmeter to the 2.5.67-mm1 kernel. If you would consider > putting it in your tree that would be great and I would work on porting the > rest of the architectures. > > http://prdownloads.sourceforge.net/lse/lockmeter1.5-2.5.67-mm1.patch?download OK, that's pretty unintrusive.