From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by vger.rutgers.edu via listexpand id ; Wed, 12 Apr 2000 06:08:23 -0400 Received: by vger.rutgers.edu id ; Wed, 12 Apr 2000 06:07:38 -0400 Received: from smtp1.cern.ch ([137.138.128.38]:4397 "EHLO smtp1.cern.ch") by vger.rutgers.edu with ESMTP id ; Wed, 12 Apr 2000 06:02:04 -0400 Date: Wed, 12 Apr 2000 12:02:44 +0200 From: Jamie Lokier To: Manfred Spraul Cc: Andrea Arcangeli , "Stephen C. Tweedie" , "David S. Miller" , alan@lxorguk.ukuu.org.uk, kanoj@google.engr.sgi.com, linux-kernel@vger.rutgers.edu, linux-mm@kvack.org, torvalds@transmeta.com Subject: Re: zap_page_range(): TLB flush race Message-ID: <20000412120244.G24128@pcep-jamie.cern.ch> References: <38F364B3.5A4A45D9@colorfullife.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 0.95.4us In-Reply-To: <38F364B3.5A4A45D9@colorfullife.com>; from Manfred Spraul on Tue, Apr 11, 2000 at 07:45:23PM +0200 Sender: owner-linux-kernel@vger.rutgers.edu Manfred Spraul wrote: > Can we ignore the munmap+access case? > I'd say that if 2 threads race with munmap+access, then the behaviour is > undefined. > Tlb flushes are expensive, I'd like to avoid the second tlb flush as in > Kanoj's patch. No, you can't ignore it. A variation called mprotect+access is used by garbage collection systems that expect to receive SEGVs when access is to a protected region. At very least, you'd have to document the race very clearly, and provide a workaround. -- Jamie - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/