From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: with ECARTIS (v1.0.0; list xfs); Thu, 09 Aug 2007 04:34:16 -0700 (PDT) Received: from larry.melbourne.sgi.com (larry.melbourne.sgi.com [134.14.52.130]) by oss.sgi.com (8.12.10/8.12.10/SuSE Linux 0.7) with SMTP id l79BY6bm003760 for ; Thu, 9 Aug 2007 04:34:10 -0700 Date: Thu, 9 Aug 2007 21:34:04 +1000 From: David Chinner Subject: [PATCH 0 of 4] Radix tree based inode caching V2 Message-ID: <20070809113404.GC12413810@sgi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Sender: xfs-bounce@oss.sgi.com Errors-to: xfs-bounce@oss.sgi.com List-Id: xfs To: xfs-dev Cc: xfs-oss One of the perpetual scaling problems XFS has is indexing it's incore inodes. We currently uses hashes and the default hash sizes chosen can only ever be a tradeoff between memory consumption and the maximum realistic size of the cache. As a result, anyone who has millions of inodes cached on a filesystem needs to tunes the size of the cache via the ihashsize mount option to allow decent scalability with inode cache operations. A further problem is the separate inode cluster hash, whose size is based on the ihashsize but is smaller, and so under certain conditions (sparse cluster cache population) this can become a limitation long before the inode hash is causing issues. The following patchset removes the inode hash and cluster hash and replaces them with radix trees to avoid the scalability limitations of the hashes. It also reduces the size of the inodes by 3 pointers.... Version 2: o collapse the original 4 patches into one o factor per-ag radix tree intialisation o convert the xfs_icluster list to use list.h constructs o make ihashsize mount option output: "XFS: ihashsize no longer used, option is deprecated." o update ihashsize docco Cheers, Dave. -- Dave Chinner Principal Engineer SGI Australian Software Group