From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758984AbYAJQaG (ORCPT ); Thu, 10 Jan 2008 11:30:06 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756378AbYAJQ3y (ORCPT ); Thu, 10 Jan 2008 11:29:54 -0500 Received: from mail.gmx.net ([213.165.64.20]:52921 "HELO mail.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1756309AbYAJQ3x (ORCPT ); Thu, 10 Jan 2008 11:29:53 -0500 X-Authenticated: #14349625 X-Provags-ID: V01U2FsdGVkX19XdWpFKlNXfZ7SFQldnl6Lr04dqua9YGcYfE3cLV zv2mVucNS7rDg/ Subject: Re: [vm] writing to UDF DVD+RW (/dev/sr0) while under memory pressure: box ==> doorstop From: Mike Galbraith To: Jan Kara Cc: Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, bfennema@falcon.csc.calpoly.edu In-Reply-To: <20080110144123.GA12331@atrey.karlin.mff.cuni.cz> References: <1199447212.4529.13.camel@homer.simson.net> <1199612533.4384.54.camel@homer.simson.net> <1199642470.3927.12.camel@homer.simson.net> <20080106122954.d8f04c98.akpm@linux-foundation.org> <1199790316.4094.57.camel@homer.simson.net> <20080108033801.40d0043a.akpm@linux-foundation.org> <1199805713.3571.12.camel@homer.simson.net> <1199806071.4174.2.camel@homer.simson.net> <1199877080.4340.19.camel@homer.simson.net> <20080109150139.311f68d3.akpm@linux-foundation.org> <20080110144123.GA12331@atrey.karlin.mff.cuni.cz> Content-Type: text/plain Date: Thu, 10 Jan 2008 16:29:50 +0100 Message-Id: <1199978990.4196.53.camel@homer.simson.net> Mime-Version: 1.0 X-Mailer: Evolution 2.12.0 Content-Transfer-Encoding: 7bit X-Y-GMX-Trusted: 0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2008-01-10 at 15:41 +0100, Jan Kara wrote: > > On Wed, 09 Jan 2008 12:11:20 +0100 > > > > > > I wonder why UDF was doing a synchronous write in there. In fact I wonder > > why it's writing the inode at all? extN doesn't do that. If for some > > reason it really does want to make the inode immediately reclaimable then > > simply shoving it down into the /dev/hda1 pagecache should be sufficient > > (ie: what you did).. > Looking at the code, I think UDF change is correct. UDF has to call > write_inode_now() because by the time clear_inode() is called, inode is > already written by VFS and prepared to be freed. But then UDF modifies > it in udf_clear_inode() (removes preallocation) and for these changes to > get to disk you have to write the inode explicitely. > But there's really no need to wait on IO. We only have to copy all > data from inode structure into buffers and that happens even if we don't > wait on sync. Perhaps I should go ahead and submit it then. There are 5 other async callers as well, so VM/UDF reclaim buglet can die, and those others can get what they asked for with net diffstat of 0. Fix udf_clear_inode() to request asynchronous writeout in icache reclaim path, and ensure that write_inore_now() honors that request, lest allocators needlessly block on iprune_mutex. Signed-off-by: Mike Galbraith diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 0fca820..f1cce24 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -657,7 +657,7 @@ int write_inode_now(struct inode *inode, int sync) int ret; struct writeback_control wbc = { .nr_to_write = LONG_MAX, - .sync_mode = WB_SYNC_ALL, + .sync_mode = sync ? WB_SYNC_ALL : WB_SYNC_NONE, .range_start = 0, .range_end = LLONG_MAX, }; diff --git a/fs/udf/inode.c b/fs/udf/inode.c index 6ff8151..d1fc116 100644 --- a/fs/udf/inode.c +++ b/fs/udf/inode.c @@ -117,7 +117,7 @@ void udf_clear_inode(struct inode *inode) udf_discard_prealloc(inode); udf_truncate_tail_extent(inode); unlock_kernel(); - write_inode_now(inode, 1); + write_inode_now(inode, 0); } kfree(UDF_I_DATA(inode)); UDF_I_DATA(inode) = NULL;