From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Sun, 2 Apr 2006 04:30:38 +1000 From: David Chinner Subject: Re: Avoid excessive time spend on concurrent slab shrinking Message-ID: <20060401183038.GY27189130@melbourne.sgi.com> References: <20060331150120.21fad488.akpm@osdl.org> <20060331153235.754deb0c.akpm@osdl.org> <20060331160032.6e437226.akpm@osdl.org> <20060331172518.40a5b03d.akpm@osdl.org> <20060401155942.E961681@wobbly.melbourne.sgi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060401155942.E961681@wobbly.melbourne.sgi.com> Sender: owner-linux-mm@kvack.org Return-Path: To: Nathan Scott Cc: Andrew Morton , Christoph Lameter , nickpiggin@yahoo.com.au, linux-mm@kvack.org, dgc@melbourne.sgi.com List-ID: On Sat, Apr 01, 2006 at 03:59:42PM +1000, Nathan Scott wrote: > On Fri, Mar 31, 2006 at 05:25:18PM -0800, Andrew Morton wrote: > > Christoph Lameter wrote: > > ... > > It appears that we're being busy in xfs_iextract(), but it would be sad if > > the problem was really lock contention in xfs_iextract(), and we just > > happened to catch it when it was running. > > > > Or maybe xfs_iextract is just slow. So this is one thing we need to get to > > the bottom of (profiles might tell us). > > I assume (profiles would be good to prove it) we are spending > time walking the hash bucket list there Christoph (while we're > holding the ch_lock spinlock on the hash bucket)? [CC'ing Dave > Chinner for any further comment, he's been looking at the chash > list for unrelated reasons recently..] You'll only get contention if something else is trying to walk the same hash chain, which tends to implicate not enough hash buckets. > If its useful for experimenting, Christoph, you can easily tweak the > cluster hash size manually by dinking with xfs_iget.c::xfs_chash_init. Just use the ihashsize mount option - the cluster hash size is proportional to the inode hash size which is changed by the ihashsize mount option. Cheers, Dave. -- Dave Chinner R&D Software Enginner SGI Australian Software Group -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org