From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263935AbTDNVNH (for ); Mon, 14 Apr 2003 17:13:07 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263936AbTDNVNH (for ); Mon, 14 Apr 2003 17:13:07 -0400 Received: from zcars04f.nortelnetworks.com ([47.129.242.57]:3205 "EHLO zcars04f.nortelnetworks.com") by vger.kernel.org with ESMTP id S263935AbTDNVNF (for ); Mon, 14 Apr 2003 17:13:05 -0400 Message-ID: <3E9B2716.6030503@nortelnetworks.com> Date: Mon, 14 Apr 2003 17:24:38 -0400 X-Sybari-Space: 00000000 00000000 00000000 From: Chris Friesen User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.8) Gecko/20020204 X-Accept-Language: en-us MIME-Version: 1.0 To: Alan Cox Cc: Bryan Shumsky , "Perez-Gonzalez, Inaky" , Linux Kernel Mailing List Subject: Re: Memory mapped files question References: <004301c302bd$ed548680$fe64a8c0@webserver> <1050349977.26521.2.camel@dhcp22.swansea.linux.org.uk> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Alan Cox wrote: > On Llu, 2003-04-14 at 20:42, Bryan Shumsky wrote: > >>Rewriting all of our code to manually handle the flushing is a MAJOR >>undertaking, so I was hoping there might be some sneaky solution you could >>come up with. Any ideas? >> > > Create a thread that does msync's every so often. Its that simple How do you deal with ensuring (or even trying to ensure) that the stuff *on disk* is sane? If I understand correctly, msync() doesn't guarantee order of writes, so randomly firing off msync() calls doesn't help. If I want to update an entry and then set a flag saying that the entry is correct, I need to have two msyncs, one for the entry data, and one for the flag. I had hoped that I could avoid this by opening the file with O_SYNC, but hpa just disabused me of that notion... Are the mmap semantics different for devices? Chris -- Chris Friesen | MailStop: 043/33/F10 Nortel Networks | work: (613) 765-0557 3500 Carling Avenue | fax: (613) 765-2986 Nepean, ON K2H 8E9 Canada | email: cfriesen@nortelnetworks.com