From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 25 Jan 2007 21:09:50 -0800 From: Andrew Morton Subject: Re: [PATCH] nfs: fix congestion control -v4 Message-Id: <20070125210950.bcdaa7f6.akpm@osdl.org> In-Reply-To: <1169739148.6189.68.camel@twins> References: <20070116054743.15358.77287.sendpatchset@schroedinger.engr.sgi.com> <20070116135325.3441f62b.akpm@osdl.org> <1168985323.5975.53.camel@lappy> <1169070763.5975.70.camel@lappy> <1169070886.6523.8.camel@lade.trondhjem.org> <1169126868.6197.55.camel@twins> <1169135375.6105.15.camel@lade.trondhjem.org> <1169199234.6197.129.camel@twins> <1169212022.6197.148.camel@twins> <1169229461.6197.154.camel@twins> <1169231212.5775.29.camel@lade.trondhjem.org> <1169276500.6197.159.camel@twins> <1169482343.6083.7.camel@lade.trondhjem.org> <1169739148.6189.68.camel@twins> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Peter Zijlstra Cc: Trond Myklebust , Christoph Lameter , linux-kernel@vger.kernel.org, linux-mm@kvack.org, pj@sgi.com List-ID: On Thu, 25 Jan 2007 16:32:28 +0100 Peter Zijlstra wrote: > Hopefully the last version ;-) > > > --- > Subject: nfs: fix congestion control > > The current NFS client congestion logic is severly broken, it marks the backing > device congested during each nfs_writepages() call but doesn't mirror this in > nfs_writepage() which makes for deadlocks. Also it implements its own waitqueue. > > Replace this by a more regular congestion implementation that puts a cap on the > number of active writeback pages and uses the bdi congestion waitqueue. > > Also always use an interruptible wait since it makes sense to be able to > SIGKILL the process even for mounts without 'intr'. > > .. > > --- linux-2.6-git.orig/include/linux/nfs_fs_sb.h 2007-01-25 16:07:03.000000000 +0100 > +++ linux-2.6-git/include/linux/nfs_fs_sb.h 2007-01-25 16:07:12.000000000 +0100 > @@ -82,6 +82,7 @@ struct nfs_server { > struct rpc_clnt * client_acl; /* ACL RPC client handle */ > struct nfs_iostats * io_stats; /* I/O statistics */ > struct backing_dev_info backing_dev_info; > + atomic_t writeback; /* number of writeback pages */ We're going to get in trouble with this sort of thing within a few years. atomic_t is 32-bit. Put 16TB of memory under writeback and blam. -- 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