Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 29 Aug 2002 17:42:08 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 29 Aug 2002 17:42:08 -0400 Received: from 2-210.ctame701-1.telepar.net.br ([200.193.160.210]:8324 "EHLO 2-210.ctame701-1.telepar.net.br") by vger.kernel.org with ESMTP id ; Thu, 29 Aug 2002 17:42:07 -0400 Date: Thu, 29 Aug 2002 18:46:15 -0300 (BRT) From: Rik van Riel X-X-Sender: riel@imladris.surriel.com To: Andrew Morton cc: Robert Love , , Subject: Re: [PATCH] low-latency zap_page_range() In-Reply-To: <3D6E9084.820B2608@zip.com.au> Message-ID: X-spambait: aardvark@kernelnewbies.org X-spammeplease: aardvark@nl.linux.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 Content-Length: 1006 Lines: 31 On Thu, 29 Aug 2002, Andrew Morton wrote: > > So we know it is held forever and a day... but is there contention? > > I'm sure there is, but nobody has measured the right workload. > > Two CLONE_MM threads, one running mmap()/munmap(), the other trying > to fault in some pages. I'm sure someone has some vital application > which does exactly this. They always do :( Can't fix this one. The mmap()/munmap() needs to have the mmap_sem for writing as long as its setting up or tearing down a VMA while the pagefault path takes the mmap_sem for reading. It might be fixable in some dirty way, but I doubt that'll ever be worth it. regards, Rik -- Bravely reimplemented by the knights who say "NIH". http://www.surriel.com/ http://distro.conectiva.com/ - 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/