From: Trond Myklebust Subject: Re: READDIRPLUS max mount option Date: Fri, 07 Mar 2008 14:59:37 -0500 Message-ID: <1204919978.16746.12.camel@heimdal.trondhjem.org> References: <47D1995E.6060501@krose.org> Mime-Version: 1.0 Content-Type: text/plain Cc: Linux Kernel Mailing List , linux-nfs@vger.kernel.org To: Kyle Rose Return-path: Received: from pat.uio.no ([129.240.10.15]:41596 "EHLO pat.uio.no" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750718AbYCGT7m (ORCPT ); Fri, 7 Mar 2008 14:59:42 -0500 In-Reply-To: <47D1995E.6060501-x8616dYPWyvYtjvyW6yDsg@public.gmane.org> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Fri, 2008-03-07 at 14:37 -0500, Kyle Rose wrote: > I have a very specific use for an NFS mount over a WAN, and allowing for > much larger expected READDIRPLUS requests actually improves performance > by at least a factor of 10 by eliminating the round-trip latency that > results from the application's single-threaded > readdir/stat/stat/stat/... behavior. Rather than maintain a hacked > kernel on my end, I'd rather the READDIRPLUS limit be a mount option. > Hence, the following patch. It defaults to the old behavior > (8*PAGE_SIZE), but with a properly-prepared mount binary will allow the > client to specify a limit. > > I'm not subscribed to the list, so please CC me in any relevant discussion. > > Kyle (adding cc to linux-nfs@vger.kernel.org) The binary mount format is frozen forever, so the changes to nfs_mount.h and nfs4_mount.h are definitely NACKed. Otherwise, it would be nice to know why this absolutely has to be made a mount option rather than just having a system-wide option (either a module/boot parameter or a sysctl) to control the behaviour of all mounts. Cheers Trond