Return-Path: Received: from newpeace.netnation.com ([204.174.223.7]:59469 "EHLO peace.netnation.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1756135AbZICUFx (ORCPT ); Thu, 3 Sep 2009 16:05:53 -0400 Date: Thu, 3 Sep 2009 13:05:50 -0700 From: Simon Kirby To: Trond Myklebust Cc: Yohan , Andrew Morton , linux-kernel@vger.kernel.org, linux-nfs@vger.kernel.org, Neil Brown , "J. Bruce Fields" , mikevs@xs4all.net Subject: Re: VM issue causing high CPU loads Message-ID: <20090903200550.GB5257@hostway.ca> References: <4A92A25A.4050608@yohan.staff.proxad.net> <20090824162155.ce323f08.akpm@linux-foundation.org> <4A96463E.5080002@corp.free.fr> <4A9C34F8.2010307@corp.free.fr> <20090902170642.f4381c1d.akpm@linux-foundation.org> <1251982884.18338.9.camel@heimdal.trondhjem.org> <4A9FC719.9020104@corp.free.fr> <1251986526.18338.29.camel@heimdal.trondhjem.org> Content-Type: text/plain; charset=us-ascii In-Reply-To: <1251986526.18338.29.camel@heimdal.trondhjem.org> Sender: linux-nfs-owner@vger.kernel.org List-ID: MIME-Version: 1.0 On Thu, Sep 03, 2009 at 10:02:06AM -0400, Trond Myklebust wrote: > OK, so 16 hash buckets are likely to be filled with ~10^6 entries each. > I can see that might be a performance issue... We have a similar setup with millions of UIDs over NFS (currently NFSv3). I _wish_ there were a way to use NFSv4 without having to use name-mapped UIDs and GIDs, since our user and group names come from MySQL anyway, and are guaranteed to be consistent across machines. Why on earth does NFSv4 force the use of names? I was considering hacking the code to stick IDs in there anyway, but I haven't looked at the feasibility of this. I suspect this would break or complicate other things, but the current NFSv4 design just seems like an incredible waste for this case. Simon-